CNY70 Vishay Semiconductors Reflective Optical Sensor with Transistor Output Marking area FEATURES • Package type: leaded • Detector type: phototransistor • Dimensions (L x W x H in mm): 7 x 7 x 6 E 21835 D Top view 19158_1 DESCRIPTION The CNY70 is a reflective sensor that includes an infrared emitter and phototransistor in a leaded package which blocks visible light. • Peak operating distance: < 0.5 mm • Operating range within > 20 % relative collector current: 0 mm to 5 mm • Typical output current under test: IC = 1 mA • Emitter wavelength: 950 nm • Daylight blocking filter • Lead (Pb)-free soldering released • Compliant to RoHS directive 2002/95/EC accordance to WEEE 2002/96/EC and in APPLICATIONS • Optoelectronic scanning and switching devices i.e., index sensing, coded disk scanning etc. (optoelectronic encoder assemblies). PRODUCT SUMMARY PART NUMBER DISTANCE FOR MAXIMUM CTRrel (1) (mm) DISTANCE RANGE FOR RELATIVE Iout > 20 % (mm) TYPICAL OUTPUT CURRENT UNDER TEST (2) (mA) DAYLIGHT BLOCKING FILTER INTEGRATED 0 0 to 5 1 Yes CNY70 Notes CTR: current transfere ratio, Iout/Iin (2) Conditions like in table basic charactristics/sensors (1) ORDERING INFORMATION ORDERING CODE CNY70 PACKAGING VOLUME (1) REMARKS Tube MOQ: 4000 pcs, 80 pcs/tube - Note MOQ: minimum order quantity (1) ABSOLUTE MAXIMUM RATINGS PARAMETER (1) TEST CONDITION SYMBOL VALUE UNIT mW COUPLER Tamb ≤ 25 °C Ptot 200 Ambient temperature range Tamb - 40 to + 85 °C Storage temperature range Tstg - 40 to + 100 °C Tsd 260 °C Total power dissipation Soldering temperature Distance to case 2 mm, t ≤ 5 s INPUT (EMITTER) Reverse voltage VR 5 V Forward current IF 50 mA Forward surge current Power dissipation tp ≤ 10 µs IFSM 3 A Tamb ≤ 25 °C PV 100 mW Tj 100 °C Junction temperature Document Number: 83751 Rev. 1.7, 17-Aug-09 For technical questions, contact: www.vishay.com 1 CNY70 Reflective Optical Sensor with Transistor Output Vishay Semiconductors ABSOLUTE MAXIMUM RATINGS PARAMETER (1) TEST CONDITION SYMBOL VALUE UNIT Collector emitter voltage VCEO 32 V Emitter collector voltage VECO 7 V IC 50 mA PV 100 mW Tj 100 °C OUTPUT (DETECTOR) Collector current Tamb ≤ 25 °C Power dissipation Junction temperature Note Tamb = 25 °C, unless otherwise specified (1) ABSOLUTE MAXIMUM RATINGS P - Power Dissipation (mW) 300 Coupled device 200 Phototransistor 100 IR - diode 0 25 0 95 11071 75 50 100 Tamb - Ambient Temperature (°C) Fig. 1 - Power Dissipation vs. Ambient Temperature BASIC CHARACTERISTICS (1) PARAMETER TEST CONDITION SYMBOL MIN. TYP. Collector current VCE = 5 V, IF = 20 mA, d = 0.3 mm (figure 1) IC (2) 0.3 1.0 Cross talk current VCE = 5 V, IF = 20 mA, (figure 2) ICX (3) 600 nA IF = 20 mA, IC = 0.1 mA, d = 0.3 mm (figure 1) VCEsat (2) 0.3 V Forward voltage IF = 50 mA VF Radiant intensity IF = 50 mA, tp = 20 ms Ie IF = 100 mA λP Method: 63 % encircled energy d MAX. UNIT COUPLER Collector emitter saturation voltage mA INPUT (EMITTER) Peak wavelength Virtual source diameter 1.25 1.6 V 7.5 mW/sr 940 nm 1.2 mm OUTPUT (DETECTOR) Collector emitter voltage IC = 1 mA VCEO 32 V Emitter collector voltage IE = 100 µA VECO 5 V VCE = 20 V, IF = 0 A, E = 0 lx ICEO Collector dark current 200 nA Notes (1) T amb = 25 °C, unless otherwise specified (2) Measured with the "Kodak neutral test card", white side with 90 % diffuse reflectance (3) Measured without reflecting medium www.vishay.com 2 For technical questions, contact: Document Number: 83751 Rev. 1.7, 17-Aug-09 CNY70 Reflective Optical Sensor with Transistor Output Vishay Semiconductors Reflecting medium (Kodak neutral test card) ~ ~~ ~ ~~ d Detector Emitter A C C E 95 10808 Fig. 2 - Pulse diagram BASIC CHARACTERISTICS Tamb = 25 °C, unless otherwise specified 10 IC - Collector Current (mA) IF - Forward Current (mA) 1000 100 10 1 1 0.1 0.01 0.1 0.001 0.1 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 VF - Forward Voltage (V) 96 11862 I F = 20 mA 1.2 d = 0.3 mm I C - Collector Current (mA) CTR rel - Relative Current Transfer Ratio 10 1.3 1.1 1.0 0.9 0.8 0.7 10 100 Fig. 5 - Collector Current vs. Forward Current 1.5 VCE = 5 V 1 I F - Forward Current (mA) 95 11065 Fig. 3 - Forward Current vs. Forward Voltage 1.4 Kodak neutral card (white side) d = 0.3 mm VCE = 5 V Kodak neutral card (white side) d = 0.3 mm I F = 50 mA 20 mA 1 10 mA 5 mA 0.1 2 mA 0.01 1 mA 0.6 0.5 - 30 - 20 -10 0 10 20 30 40 50 60 70 80 96 11913 Tamb - Ambient Temperature (°C) Fig. 4 - Relative Current Transfer Ratio vs. Ambient Temperature Document Number: 83751 Rev. 1.7, 17-Aug-09 For technical questions, contact: 0.001 0.1 95 11066 1 10 100 VCE - Collector Emitter Voltage (V) Fig. 6 - Collector Current vs. Collector Emitter Voltage www.vishay.com 3 CNY70 Reflective Optical Sensor with Transistor Output Vishay Semiconductors 10 Kodak neutral card (white side) d = 0.3 mm V CE = 5 V I C - Collector Current (mA) CTR - Current Transfer Ratio (%) 100 10 1 0.1 0.1 1 10 d 0.1 V CE = 5 V I F = 20 mA 0.001 0 100 I F - Forward Current (mA) 96 11914 1 2 Fig. 7 - Current Transfer Ratio vs. Forward Current 6 4 8 10 d - Distance (mm) 95 11069 Fig. 9 - Collector Current vs. Distance 0° 10° 20° I erel - Relative Radiant Intensity Icrel - Relative Collector Current CTR - Current Transfer Ratio (%) 10 I F = 50 mA 1 mA 20 mA 10 mA 1 5 mA 2 mA Kodak neutral card (white side) d = 0.3 mm 30° 40° 1.0 0.9 50° 0.8 60° 70° 0.7 80° 0.1 0.1 0.6 100 1 10 V CE - Collector Emitter Voltage (V) 96 12001 0.2 0.4 0 0.2 0.4 0.6 95 11063 Fig. 8 - Current Transfer Ratio vs. Collector Emitter Voltage Fig. 10 - Relative Radiant Intensity/Collector Current vs. Angular Displacement I Crel - Relative Collector Current 1.0 0.9 E d = 5 mm 4 mm 3 mm 2 mm 1 mm 0 0.7 0.6 0.5 0.4 s D 5 mm 10 mm d 0 E s 5 mm D 0.3 10 mm VCE = 5 V I F = 20 mA 0.2 0.1 0.0 0 96 11915 0 1.5 0.8 1 2 3 4 5 6 7 8 9 10 11 s - Displacement (mm) Fig. 11 - Relative Collector Current vs. Displacement www.vishay.com 4 For technical questions, contact: Document Number: 83751 Rev. 1.7, 17-Aug-09 CNY70 Reflective Optical Sensor with Transistor Output Vishay Semiconductors PACKAGE DIMENSIONS in millimeters 95 11345 TUBE DIMENSIONS in millimeters 20291 Document Number: 83751 Rev. 1.7, 17-Aug-09 For technical questions, contact: sensorstechsupport@vishay.com www.vishay.com 5 Legal Disclaimer Notice Vishay Disclaimer All product specifications and data are subject to change without notice. Vishay Intertechnology, Inc., its affiliates, agents, and employees, and all persons acting on its or their behalf (collectively, “Vishay”), disclaim any and all liability for any errors, inaccuracies or incompleteness contained herein or in any other disclosure relating to any product. Vishay disclaims any and all liability arising out of the use or application of any product described herein or of any information provided herein to the maximum extent permitted by law. The product specifications do not expand or otherwise modify Vishay’s terms and conditions of purchase, including but not limited to the warranty expressed therein, which apply to these products. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document or by any conduct of Vishay. The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications unless otherwise expressly indicated. Customers using or selling Vishay products not expressly indicated for use in such applications do so entirely at their own risk and agree to fully indemnify Vishay for any damages arising or resulting from such use or sale. Please contact authorized Vishay personnel to obtain written terms and conditions regarding products designed for such applications. Product names and markings noted herein may be trademarks of their respective owners. Document Number: 91000 Revision: 18-Jul-08 www.vishay.com 1 Page 1 Vishay Semiconductors Application of Optical Reflex Sensors TCRT1000, TCRT5000, CNY70 Vishay Semiconductor optoelectronic sensors contain infrared-emitting diodes as a radiation source and phototransistors as detectors. Typical applications include: Copying machines Printers Video recorders Object counters Proximity switch Industrial control Vending machines Special features: Compact design Ambient light protected Operation range 0 to 20 mm Cut-off frequency up to 40 kHz High sensitivity High quality level, ISO 9000 Low dark current Automated high-volume production Minimized crosstalk These sensors present the quality of perfected products. The components are based on Vishay Semiconductor’s many years’ experience as one of Europe’s largest producers of optoelectronic components. Sensor Drawings 94 9442 94 9318 TCRT1000 TCRT5000 94 9320 CNY70 www.vishay.com 1 Document Number 80107 02-02 Page 1 Page 2 Vishay Semiconductors Optoelectronic Sensors In many applications, optoelectronic transmitters and receivers are used in pairs and linked together optically. Manufacturers fabricate them in suitable forms. They are available for a wide range of applications as ready-to-use components known as couplers, transmissive sensors (or interrupters), reflex couplers and reflex sensors. Increased automation in industry in particular has heightened the demand for these components and stimulated the development of new types. General Principles The operating principles of reflex sensors are similar to those of transmissive sensors. Basically, the light emitted by the transmitter is influenced by an object or a medium on its way to the detector. The change in the light signal caused by the interaction with the object then produces a change in the electrical signal in the optoelectronic receiver. The main difference between reflex couplers and transmissive sensors is in the relative position of the transmitter and detector with respect to each other. In the case of the transmissive sensor, the receiver is opposite the transmitter in the same optical axis, giving a direct light coupling between the two. In the case of the reflex sensor, the detector is positioned next to the transmitter, avoiding a direct light coupling. The transmissive sensor is used in most applications for small distances and narrow objects. The reflex sensor, however, is used for a wide range of distances as well as for materials and objects of different shapes. In the following chapters, we will deal with reflex sensors placing particular emphasis on their practical use. The components TCRT1000, TCRT5000 and CNY70 are used as examples. However, references made to these components and their use apply to all sensors of a similar design. The reflex sensors TCRT1000, TCRT5000 and CNY70 contain IR-emitting diodes as transmitters and phototransistors as receivers. The transmitters emit radiation of a wavelength of 950 nm. The spectral sensitivity of the phototransistors are optimized at this wavelength. There are no focusing elements in the sensors described, though lenses are incorporated inside the TCRT5000 in both active parts (emitter and detector). The angular characteristics of both are divergent. This is necessary to realize a position-independent function for easy practical use with different reflecting objects. In the case of TCRT5000, the concentration of the beam pattern to an angle of 16° for the emitter and 30° for the detector results in operation at an increased range with optimized resolution. The emitting and acceptance angles in the other reflex sensors are about 45°. This is an advantage in short distance operation. The main difference between the sensor types is the mechanical outline (as shown in the figures, see previous page ), resulting in various electrical parameters and optical properties. A specialization for certain applications is necessary. Measurements and statements on the data of the reflex sensors are made relative to a reference surface with defined properties and precisely known reflecting properties. This reference medium is the diffusely reflecting Kodak neutral card, also known as gray card (KODAK neutral test card; KODAK publi-cation No. Q-13, CAT 1527654). It is also used here as the reference medium for all details. The reflection factor of the white side of the card is 90% and that of the gray side is 18%. Table 1 shows the measured reflection of a number of materials which are important for the practical use of sensors. The values of the collector current given are relative and correspond to the reflection of the various surfaces with regard to the sensor’s receiver. They were measured at a transmitter current of IF = 20 mA and at a distance of the maximum light coupling. These values apply to all reflex sensors. The ‘black-on-white paper’ section stands out in table 1. Although all surfaces appear black to the ‘naked eye’, the black surfaces emit quite different reflections at a wavelength of 950 nm. It is particularly important to account for this fact when using reflex sensors. The reflection of the various body surfaces in the infrared range can deviate significantly from that in the visible range. www.vishay.com 2 Document Number 80107 02-02 Page 2 Page 3 Vishay Semiconductors Table 1. Relative collector current (or coupling factor) of the reflex sensors for reflection on various materials. Reference is the white side of the Kodak neutral card. The sensor is positioned perpendicular to the surface. The wavelength is 950 nm. ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Kodak neutral card White side (reference medium) Gray side Paper Typewriting paper Drawing card, white (Schoeller Durex) Card, light gray Envelope (beige) Packing card (light brown) Newspaper paper Pergament paper Black on white typewriting paper Drawing ink (Higgins, Pelikan, Rotring) Foil ink (Rotring) Fiber-tip pen (Edding 400) Fiber-tip pen, black (Stabilo) Photocopy Plotter pen HP fiber–tip pen (0.3 mm) Black 24 needle printer (EPSON LQ-500) Ink (Pelikan) Pencil, HB 100% 20% 94% 100% 67% 100% 84% 97% 30-42% 4-6% 50% 10% 76% 7% 84% 28% 100% 26% ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Plastics, glass White PVC Gray PVC Blue, green, yellow, red PVC White polyethylene White polystyrene Gray partinax Fiber glass board material Without copper coating With copper coating on the reverse side Glass, 1 mm thick Plexiglass, 1 mm thick Metals Aluminum, bright Aluminum, black anodized Cast aluminum, matt Copper, matt (not oxidized) Brass, bright Gold plating, matt Textiles White cotton Black velvet 90% 11% 40-80% 90% 120% 9% 12-19% 30% 9% 10% 110% 60% 45% 110% 160% 150% 110% 1.5% Parameters and Practical Use of the Reflex Sensors A reflex sensor is used in order to receive a reflected signal from an object. This signal gives information on the position, movement, size or condition (e.g. coding) of the object in question. The parameter that describes the function of the optical coupling precisely is the so-called optical transfer function (OT) of the sensor. It is the ratio of the received to the emitted radiant power. OT r e Additional parameters of the sensor, such as operating range, the resolution of optical distance of the object, the sensitivity and the switching point in the case of local changes in the reflection, are directly related to this optical transfer function. In the case of reflex sensors with phototransistors as receivers, the ratio Ic/IF (the ratio of collector current Ic to the forward current IF) of the diode emitter is preferred to the optical transfer function. As with optocouplers, Ic/IF is generally known as the coupling factor, k. The following approximate relationship exists between k and OT: k = Ic/ IF = [(S B)/h] r/e where B is the current amplification, S = Ib/Φr (phototransistor’s spectral sensitivity), and h = IF/Φe (proportionality factor between IF and Φe of the transmitter). www.vishay.com 3 Document Number 80107 02-02 Page 3 Page 4 Vishay Semiconductors In figures7 and 8, the curves of the radiant intensity, Ie, of the transmitter to the forward current, IF, and the sensitivity of the detector to the irradiance, Ee, are shown respectively. The gradients of both are equal to unity slope. This represents a measure of the deviation of the curves from the ideal linearity of the parameters. There is a good proportionality between Ie and IF and between Ic and Ee where the curves are parallel to the unity gradient. Greater proportionality improves the relationship between the coupling factor, k, and the optical transfer function. surface and the frequency that is, the speed of reflection change. For all reflex sensors, the curve of the coupling factor as a function of the transmitter current, IF, has a flat maximum at approximately 30 mA (figure 9). As shown in the figure, the curve of the coupling factor follows that of the current amplification, B, of the phototransistor. The influence of temperature on the coupling factor is relatively small and changes approximately –10% in the range of –10 to +70°C (figure 10). This fairly favorable temperature compensation is attributable to the opposing temperature coefficient of the IR diode and the phototransistor. The maximum speed of a reflection change that is detectable by the sensor as a signal is dependent either on the switching times or the threshold frequency, fc, of the component. The threshold frequency and the switching times of the reflex sensors TCRT1000, TCRT5000, and CNY70 are determined by the slowest component in the system in this case the phototransistor. As usual, the threshold frequency, fc, is defined as the frequency at which the value of the coupling factor has fallen by 3 dB (approximately 30%) of its initial value. As the frequency increases, f > fc, the coupling factor decreases. Figure 7. Radiant intensity, Ie = f (IF), of the IR transmitter Coupling Factor, k In the case of reflex couplers, the specification of the coupling factor is only useful by a defined reflection and distance. Its value is given as a percentage and refers here to the diffuse reflection (90%) of the white side of Kodak neutral card at the distance of the maximum light coupling. Apart from the transmitter current, IF, and the temperature, the coupling factor also depends on the distance from the reflecting Figure 8. Sensitivity of the reflex sensors’ detector www.vishay.com 4 Document Number 80107 02-02 Page 4 Page 5 Vishay Semiconductors from the diagram fc as a function of the load resistance, RL. Working Diagram The dependence of the phototransistor collector current on the distance, A, of the reflecting medium is shown in figures 12 and 13 for the reflex sensor TCRT1000. Figure 9. Coupling factor k = f (IF) of the reflex sensors The data were recorded for the Kodak neutral card with 90% diffuse reflection serving as the reflecting surface, arranged perpendicular to the sensor. The distance, A, was measured from the surface of the reflex sensor. The emitter current, IF, was held constant during the measurement. Therefore, this curve also shows the course of the coupling factor and the optical transfer function over distance. It is called the working diagram of the reflex sensor. The working diagrams of all sensors (figure 12) shows a maximum at a certain distance, Ao. Here the optical coupling is the strongest. For larger distances, the collector current falls in accordance with the square law. When the amplitude, I, has fallen not more than 50% of its maximum value, the operation range is at its optimum. Figure 10. Change of the coupling factor, k, with temperature, T As a consequence, the reflection change is no longer easily identified. Figure 11 illustrates the change of the cut-off frequency at collector emitter voltages of 5, 10 and 20 V and various load resistances. Higher voltages and low load resistances significantly increase the cut-off frequency. The cut-off frequencies of all Vishay Semiconductor reflex sensors are high enough (with 30 to 50 kHz) to recognize extremely fast mechanical events. In practice, it is not recommended to use a large load resistance to obtain a large signal, dependent on the speed of the reflection change. Instead, the opposite effect takes place, since the signal amplitude is markedly reduced by the decrease in the cut-off frequency. In practice, the better approach is to use the given data of the application (such as the type of mechanical movement or the number of markings on the reflective medium). With these given data, the maximum speed at which the reflection changes can be determined, thus allowing the maximum frequency occurring to be calculated. The maximum permissible load resistance can then be selected for this frequency Figure 11. Cut-off frequency, fc www.vishay.com 5 Document Number 80107 02-02 Page 5 Page 6 Vishay Semiconductors a) TCRT5000 c) TCRT1000 b) CNY 70 Figure 12. Working diagram of reflex sensors TCRT5000, CNY70 and TCRT1000 Resolution, Trip Point The behavior of the sensors with respect to abrupt changes in the reflection over a displacement path is determined by two parameters: the resolution and the trip point. If a reflex sensor is guided over a reflecting surface with a reflection surge, the radiation reflected back to the detector changes gradually, not abruptly. This is depicted in figure 13a. The surface, g, seen jointly by the transmitter and detector, determines the radiation received by the sensor. During the movement, this surface is gradually covered by the dark reflection range. In accordance with the curve of the radiation detected, the change in collector current is not abrupt, but undergoes a wide, gradual transition from the higher to the lower value. As illustrated in figure 13b, the collector current falls to the value Ic2, which corresponds to the reflection of the dark range, not at the point Xo, but at the points Xo + Xd/2, displaced by Xd/2. The displacement of the signal corresponds to an uncertainty when recording the position of the reflection change, and it determines the resolution and the trip point of the sensor. The trip point is the position at which the sensor has completely recorded the light/ dark transition, that is, the range between the points Xo + Xd/2 and Xo – Xd/2 around Xo. The displacement, Xd, therefore, corresponds to the width or the tolerance of the trip point. In practice, the section lying between 10 and 90% of the difference Ic = Ic1 – Ic2 is taken as Xd. This corresponds to the rise time of the generated signal since there is both movement and speed. Analogous to switching time, displacement, Xd, is described as a switching distance. www.vishay.com 6 Document Number 80107 02-02 Page 6 Page 7 Vishay Semiconductors The resolution is the sensor’s capability to recognize small structures. Figure 13 illustrates the example of the curve of the reflection and current signal for a black line measuring d in width on a light background (e.g. on a sheet of paper). The line has two light/ dark transitions the switching distance Xd/2 is, therefore, effective twice. Reflection R1 Line d = line width R2 d Collector current X IC1 Xd < line width IC2 a) Collector current Xd X IC1 IC2 Xd > line width g Xd X Figure 14. Reflection of a line of width d and corresponding curve of the collector current Ic b) Figure 14 shows the dependence of the switching distance, Xd, on the distance A with the sensors placed in two different positions with respect to the separation line of the light/ dark transition. The curves marked position 1 in the diagrams correspond to the first position. The transmitter/ detector axis of the sensor was perpendicular to the separation line of the transition. In the second position (curve 2), the transmitter/ detector axis was parallel to the transition. In the first position (1) all reflex sensors have a better resolution (smaller switching distances) than in position 2. It can recognize lines smaller than half a millimeter at a distance below 0.5 mm. Figure 13. Abrupt reflection change with associated Ic curve The line is clearly recognized as long as the line width is d Xd. If the width is less than Xd, the collector current change, Ic1 – Ic2, that is the processable signal, becomes increasingly small and recognition increasingly uncertain. The switching distance or better its inverse can therefore be taken as a resolution of the sensor. The switching distance, Xd, is predominantly dependent on the mechanical/ optical design of the sensor and the distance to the reflecting surface. It is also influenced by the relative position of the transmitter/ detector axis. It should be remarked that the diagram of TCRT5000 is scaled up to 10 cm. It shows best resolution between 2 and 10 cm. All sensors show the peculiarity that the maximum resolution is not at the point of maximum light coupling, Ao, but at shorter distances. In many cases, a reflex sensor is used to detect an object that moves at a distance in front of a background, such as a sheet of paper, a band or a plate. In contrast to the examples examined above, the distances of the object surface and background from the sensor vary. www.vishay.com 7 Document Number 80107 02-02 Page 7 Page 8 Vishay Semiconductors Since the radiation received by the sensor’s detector depends greatly on the distance, the case may arise when the difference between the radiation reflected by the object on the background is completely equalized by the distance despite varying reflectance factors. Even if the sensor has sufficient resolution, it will no longer supply a processable signal due to the low reflection difference. In such applications it is necessary to examine whether there is a sufficient contrast. This is performed with the help of the working diagram of the sensor and the reflectance factors of the materials. a) TCRT5000 c) TCRT1000 b) CNY70 Figure 15. The switching distance as a function of the distance A for the reflex sensors TCRT5000, CNY70 andTCRT1000 www.vishay.com 8 Document Number 80107 02-02 Page 8 Page 9 Vishay Semiconductors Sensitivity, Dark Current and Crosstalk The lowest photoelectric current that can be processed as a useful signal in the sensor’s detector determines the weakest usable reflection and defines the sensitivity of the reflex sensor. This is determined by two parameters – the dark current of the phototransistor and the crosstalk. The phototransistor as receiver exhibits a small dark current, ICEO, of a few nA at 25°C. However, it is dependent on the applied collector-emitter voltage, VCE, and to a much greater extent on the temperature, T (see figure 16). The crosstalk between the transmitter and detector of the reflex sensor is given with the current, Icx. Icx is the collector current of the photoelectric transistor measured at normal IR transmitter operating conditions without a reflecting medium. For design and optical reasons, the transmitter and detector are mounted very close to each other. Electrical interference signals can be generated in the detector when the transmitter is operated with a pulsed or modulated signal. The transfer capability of the interference increases strongly with the frequency. Steep pulse edges in the transmitter’s current are particularly effective here since they possess a large portion of high frequencies. For all Vishay Semiconductor sensors, the ac crosstalk, Icxac, does not become effective until frequencies of 4 MHz upwards with a transmission of approximately 3 dB between the transmitter and detector. The dark current and the dc - and ac crosstalk form the overall collector fault current, Icf. It must be observed that the dc-crosstalk current, Icxdc, also contains the dark current, ICEO, of the phototransistor. Icf = Icxdc + Icxac This current determines the sensitivity of the reflex sensor. The collector current caused by a reflection change should always be at least twice as high as the fault current so that a processable signal can be reliably identified by the sensor. Ambient Light Ambient light is another feature that can impair the sensitivity and, in some circumstances, the entire function of the reflex sensor. However, this is not an artifact of the component, but an application specific characteristic. Figure 16. Temperature-dependence of the collector dark current It is ensured that no (ambient) light falls onto the photoelectric transistor. This determines how far it is possible to guarantee avoiding a direct optical connection between the transmitter and detector of the sensor. At IF = 20 mA, the current Icx is approximately 15 nA for the CNY70, TCRT1000 and TCRT5000. Icx can also be manifested dynamically. In this case, the origin of the crosstalk is electrical rather than optical. The effect of ambient light falling directly on the detector is always very troublesome. Weak steady light reduces the sensor’s sensitivity. Strong steady light can, depending on the dimensioning (RL, VC), saturate the photoelectric transistor. The sensor is ‘blind’ in this condition. It can no longer recognize any reflection change. Chopped ambient light gives rise to incorrect signals and feigns non-existent reflection changes. Indirect ambient light, that is ambient light falling onto the reflecting objects, mainly reduces the contrast between the object and background or the feature and surroundings. The interference caused by ambient light is predominantly determined by the various reflection properties of the material which in turn are dependent on the wavelength. www.vishay.com 9 Document Number 80107 02-02 Page 9 Page 10 Vishay Semiconductors If the ambient light has wavelengths for which the ratio of the reflection factors of the object and background is the same or similar, its influence on the sensor’s function is small. Its effect can be ignored for intensities that are not excessively large. On the other hand, the object/ background reflection factors can differ from each other in such a way that, for example, the background reflects the ambient light much more than the object. In this case, the contrast disappears and the object cannot be detected. It is also possible that an uninteresting object or feature is detected by the sensor because it reflects the ambient light much more than its surroundings. determine the ambient light and its effects precisely. Therefore, an attempt to keep its influence to a minimum is made from the outset by using a suitable mechanical design and optical filters. The detectors of the sensors are equipped with optical filters to block such visible light. Furthermore, the mechanical design of these components is such that it is not possible for ambient light to fall directly or sideways onto the detector for object distances of up to 2 mm. In practice, ambient light stems most frequently from filament, fluorescent or energysaving lamps. Table 2 gives a few approximate values of the irradiance of these sources. The values apply to a distance of approximately 50 cm, the spectral range to a distance of 850 to 1050 nm. The values of table 2 are only intended as guidelines for estimating the expected ambient radiation. AC operation of the reflex sensors offers the most effective protection against ambient light. Pulsed operation is also helpful in some cases. In practical applications, it is generally rather difficult to If the ambient light source is known and is relatively weak, in most cases it is enough to estimate the expected power of this light on the irradiated area and to consider the result when dimensioning the circuit. Compared with dc operation, the advantages are greater transmitter power and at the same time significantly greater protection against faults. The only disadvantage is the greater circuit complexity, which is necessary in this case. The circuit in figure 20 is an example of operation with chopped light. Table 2. Examples for the irradiance of ambient light sources Light source (at 50 cm distance) Irradiance Ee (µW/cm 2) 850 to 1050 nm Steady light AC light (peak value) 500 25 30 14 16 Frequency (Hz) ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Filament lamp (60 W) Fluorescent lamp OSRAM (65 W) Economy lamp OSRAM DULUX (11 W) 100 100 www.vishay.com 10 Document Number 80107 02-02 Page 10 Page 11 Vishay Semiconductors Application Examples, Circuits The most important characteristics of the Vishay Semiconductor reflex sensors are summarized in table 3. The task of this table is to give a quick comparison of data for choosing the right sensor for a given application. Application Example with Dimensioning As shown in figure 17, the coupling factor is at its maximum. In addition, the degradation (i.e. the reduction of the transmitted IR output with aging) is minimum for currents under 40 mA (< 10% for 10000 h) and the self heating is low due to the power loss (approximately 50 mW at 40 mA). With a simple application example, the dimensioning of the reflex sensor can be shown in the basic circuit with the aid of the component data and considering the boundary conditions of the application. The reflex sensor is used for speed control. An aluminum disk with radial strips as markings fitted to the motor shaft forms the reflecting object and is located approximately 3 mm in front of the sensor. The sensor signal is sent to a logic gate for further processing. Dimensioning is based on dc operation, due to the simplified circuitry. The optimum transmitter current. IF, for dc operation is between 20 and 40 mA. IF = 20 mA is selected in this case. +5 V TCRT5000 74HCTXX Q RS 180 RE 15 k GND Figure 17. Reflex sensor - basic circuit Table 3. ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Parameter Distance of optimum coupling Distance of best resolution Coupling factor Switching distance (min.) Optimum working distance Operating range Symbol A0 Ar k xd Xor Aor CNY70 0.3 mm 0.2 mm 5% 1.5 mm 0.2 to 3 mm 9 mm Reflex Sensor Type TCRT1000 1 mm 0.8 mm 5% 0.7 mm 0.4 to 2.2 mm 8 mm TCRT5000 2 mm 1.5 mm 6% 1.9 mm 0.2 to 6.5 mm > 20 mm Table 4. ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ Application Data Aluminum disk Diameter 50 mm, distance from the sensor 3 mm, markings printed on the aluminum Markings 8 radial black stripes and 8 spacings, the width of the stripes and spacings in front of the sensor is approximately = 4 mm (in a diameter of 20 mm) Motor speed 1000 to 3000 rpm Temperature range 10 to 60°C Ambient light 60 W fluorescent lamp, approximate distance 2 m Power supply 5 V ± 5% Position of the Position 1, sensor/ detector connecting line perpendicular to the strips sensor www.vishay.com 11 Document Number 80107 02-02 Page 11 Page 12 Vishay Semiconductors Special attention must also be made to the downstream logic gate. Only components with a low input offset current may be used. In the case of the TTL gate and the LS-TTL gate, the ILH current can be applied to the sensor output in the low condition. At –1.6 mA or –400 µA, this is above the signal current of the sensor. A transistor or an operational amplifier should be connected at the output of the sensor when TTL or LS-TTL components are used. A gate from the 74HCTxx family is used. According to the data sheet, its fault current ILH is approximately 1 µA. The expected collector current for the minimum and maximum reflection is now estimated. According to the working diagram in figure 12a, it follows that when A = 3 mm Ic = 0.95 Icmax Icmax is determined from the coupling factor, k, for IF = 10 mA. Icmax = k IF In addition, 1 µA, the fault current of the 74HCTxx gate, is also added Ic2 = 49.5 µA The effect of the indirect incident ambient light can most easily be seen by comparing the radiant powers produced by the ambient light and the sensor’s transmitter on 1 mm2 of the reflecting surface. The ambient light is then taken into account as a percentage in accordance with the ratio of the powers. From table 2: Ee (0.5 m) = 40 µW/ cm2 (dc + ac/ 2) Ee (2 m) = Ee(0.5 m) (0.5/ 2)2 (Square of the distance law) Ee (2 m) = 2.5 µW/ cm2 sf = 0.025 W The radiant power (Φsf = 0.025 µW) therefore falls on 1 mm2. At IF = 10 mA, the typical value k = 2.8% When IF = 10 mA, the sensor’s transmitter has the radiant intensity: is obtained for k from figure 9. However, this value applies to the Kodak neutral card or the reference surface. The coupling factor has a different value for the surfaces used (typewriting paper and black-fiber tip pen). The valid value for these material surfaces can be found in table 1: k1 = 94% k = 4.7% for typing paper and k2 = 10% k = 0.5% for black-tip pen (Edding) Therefore: Ic2. Crosstalk with only a few nA for the TCRT5000 is ignored. However, the dark current can increase up to 1 µA at a temperature of 70°C and should be taken into account. Ic1 = 0.95 k1 IF = 446.5 µA Ic2 = 0.95 k2 IF = 47.5 µA Ie e 0.25 Wsr (see figure 7) The solid angle for 1 mm2 surface at a distance of 3 mm is 2 1 mm 2 1 sr 9 (3 mm) It therefore follows for the radiant power that: Temperature and aging reduce the collector current. They are therefore important to Ic1 and are subtracted from it. Figure 10 shows a change in the collector current of approximately 10% for 70°C. Another 10% is deducted from Ic1 for aging Ic1 = 263 µA – (20% 263 µA) = 357.2 µA The fault current Icf (from crosstalk and collector dark current) increases the signal current and is added to e = Ie = ca. 27.8 mW The power of 0.025 µW produced by the ambient light is therefore negligibly low compared with the corresponding power (approximately 28 µW) of the transmitter. The currents Ic1, Ic2 would result in full reflecting surfaces, that is, if the sensor’s visual field only measures white or black typing paper. However, this is not the case. The reflecting surfaces exist in the form of stripes. www.vishay.com 12 Document Number 80107 02-02 Page 12 Page 13 Vishay Semiconductors The signal can be markedly reduced by the limited resolution of the sensor if the stripes are narrow. The suitable stripe width for a given distance should therefore be selected from figure 15. In this case, the minimum permissible stripe width is approximately 2.5 mm for a distance of 3 mm (position 1, figure 15a). The markings measuring 4 mm in width were expediently selected in this case. For this width, a signal reduction of about 20% can be permitted with relatively great certainty, so that 10% of the difference (Ic1 – Ic2) can be subtracted from Ic1 and added to Ic2. Ic1 = 357.2 A – 30.8 A = 326.4 A Ic2 = 49.5 A + 30.8 A = 80.3 A The suitable load resistance, RE, at the emitter of the photo-transistor is then determined from the low and high levels 0.8 V and 2.0 V for the 74HCTxx gate. RE < 0.8 V/ Ic2 and RE > 2.0 V/ Ic1, i.e., 6.1 k < RE < 9.96 k 6.8 k is selected for RE The corresponding levels for determining RE must be used if a Schmitt trigger of the 74HCTxx family is employed. The frequency limit of the reflex sensor is then determined with RE = 6.8 k and compared with the maximum operating frequency in order to check whether signal damping attributable to the frequency can occur. Figure 11 shows for Vs = 5 V and RE = 6.8 k approximately, for the TCRT5000, fc = 3.0 kHz. Sixteen black/ white stripes appear in front of the sensor in each revolution. This produces a maximum signal frequency of approximately 400 Hz for the maximum speed of 3000 rpm up to 50 rps. This is significantly less than the fc of the sensor, which means there is no risk of signal damping. In the circuit in figure 17, a resistor, Rc, can be used on the collector of the photoelectric transistor instead of RE. In this case, an inverted signal and somewhat modified dimensioning results. The current Ic1 now determines the low signal level and the current Ic2 the high. The voltages (Vs – 2 V) and (Vs – 0.8 V) and not the high level and low level 2 V and 0.8 V, are now decisive for determining the resistance, Rc. Circuits with Reflex Sensors The couple factor of the reflex sensors is relatively small. Even in the case of good reflecting surfaces, it is less than 10%. Therefore, the photocurrents are in practice only in the region of a few µA. As this is not enough to process the signals any further, an additional amplifier is necessary at the sensor output. Figure 18 shows two simple circuits with sensors and follow-up operational amplifiers. The circuit in figure 18b is a transimpedance which offers in addition to the amplification the advantage of a higher cut-off frequency for the whole layout. Two similar amplification circuits transistors are shown in figure 19. incorporating The circuit in figure 20 is a simple example for operating the reflex sensors with chopped light. It uses a pulse generator constructed with a timer IC. This pulse generator operates with the pulse duty factor of approximately 1. The frequency is set to approximately 22 kHz. On the receiver side, a conventional LC resonance circuit (fo = 22 kHz) filters the fundamental wave out of the received pulses and delievers it to an operational amplifier via the capacitor, Ck. The LC resonance circuit simultaneously represents the photo transistor’s load resistance. For direct current, the photo transistor’s load resistance is very low in this case approximately 0.4, which means that the photo transistor is practically shorted for dc ambient light. At resonance frequencies below 5 kHz, the necessary coils and capacitors for the oscillator become unwieldy and expensive. Therefore, active filters, made up with operational amplifiers or transistors, are more suitable (figures 21 and 22). It is not possible to obtain the quality characteristics of passive filters. In addition the load resistance on the emitter of the photo transistor has remarkably higher values than the dc resistance of a coil. On the other hand, the construction with active filters is more compact and cheaper. The smaller the resonance frequency becomes, the greater the advantages of active filters compared to LC resonant circuits. In some cases, reflex sensors are used to count steps or objects, while at the same time recognition of a change in the direction of rotation (= movement direction) is necessary. The circuit shown in figure 23 is suitable for such applications. The circuit is composed of two independent channels with reflex sensors. The sensor signals are formed via the Schmitt trigger into TTL impulses with step slopes, which are supplied to the pulse inputs of the binary counter 74LS393. The outputs of the 74LS393 are coupled to the reset inputs. This is made in such a way that the first output, whose condition changes from ‘low’ to ‘high’, sets the directly connected counter. In this way, the counter of the other channel is deleted and blocked. The outputs of the active counter can be displaced or connected to more electronics for evaluation. www.vishay.com 13 Document Number 80107 02-02 Page 13 Page 14 Vishay Semiconductors It should be mentioned that such a circuit is only suited to evenly distributed objects and constant movements. If this is not the case, the channels must be close to each other, so that the movement of both sensors are collected successively. The circuit also works perfectly if the last mentioned condition is fulfilled. Figure 24 shows a pulse circuit combining analog with digital components and offering the possibility of temporary storage of the signal delivered by the reflex sensor. A timer IC is used as the pulse generator. The negative pulse at the timer’s output triggers the clock input of the 74HCT74 flip-flop and, at the same a) time, the reflex sensor’s transmitter via a driver transistor. The flip-flop can be positively triggered, so that the condition of the data input at this point can be received as the edge of the pulse rises. This then remains stored until the next rising edge. The reflex sensor is therefore only active for the duration of the negative pulse and can only detect reflection changes within this time period. During the time of negative impulses, electrical and optical interferences are suppressed. A sample and hold circuit can also be employed instead of the flip-flop. This is switched on via an analog switch at the sensor output as the pulse rises. b) +10 V +10 V RF IF = 20 mA Reflex sensor IF = 20 mA Reflex sensor 220 k 7 TLC271 6 2 2 3 RS 390 7 3 Output Output 4 RE 1k TLC271 6 4 RF RE 1k RS 390 220 k RI 1k RI 1k GND GND Figure 18. Circuits with operational amplifier a) b) +10 V +10 V RC 1k RE 220 RL 1k IF = 20 mA Reflex sensor BC178B PNP IF = 20 mA CK Reflex sensor RS 390 RF Output 2.2 F RL 10 k RS 390 220 k Output BC108B PNP RE 1k GND GND Figure 19. Circuits with transistor amplifier www.vishay.com 14 Document Number 80107 02-02 Page 14 Page 15 Vishay Semiconductors VS = +5 V 82 1.2 k Reflex sensor 8 7 2.7 k 6 3 Q CV 5 DIS R THR TR 2 4 555 CK GND 100 nF 1 10 nF 100 nF C 62 nF 7 TLC 271 6 3 Output 2 4 RF L 0.86 mH 10 k 100 GND Figure 20. AC operation with oscillating circuit to suppress ambient light +VS (10 V) RS 220 Reflex sensor CF 1 nF RA 9.1 k 4 Timer 8 7 RQ 3 DIS RB 5.1 k 6 2 C R 33 k 33 k 2 7 6 1 F 3 THR TR CK R CV 5 GND 1 RE 510 555 100 nF R1 1k Cq 4 Output TLC 271 (CA3160) 22 nF 100 nF GND GND Timer dimensions: Active filter : tp (pulse width) = 0.8 RC = 400 s T (period) = 0.8 (RA + RB) C = 1 ms C Cf Cq Q fo 1(6.28 C R) Cq Cf V uo 2 R Q 2 RE Figure 21. AC operation with active filter made up of an operational amplifier, circuit and dimensions www.vishay.com 15 Document Number 80107 02-02 Page 15 Page 16 Vishay Semiconductors +VS (10 V) RV 220 CF RA 9.1 k Reflex sensor 4 Timer 8 7 RB 5.1 k 6 THR 2 TR CK RQ 3 DIS 1 CK 51 k 51 k 1 F 555 100 nF Output NPN Cq RE 1.8 k GND C R 1.5 nF R 1 F 5 CV RC 1k 33 nF 100 nF GND GND Timer dimensions: tp (pulse width) = 0.8 RC = 400 ms T (period) = 0.8 (RA + RB) C = 1 ms C Active filter : Cf C q Q Cq Cf V uo 2 R Q 2 RE fo 1(6.28 C R) Figure 22. AC operation with transistor amplifier as active filter Left A +5 V Reflex sensor Display system QA QB QC QD CLK CLR B CLK QA QB QC CLR QD LS393 A A RE RD CLK Q D 74HCT14 15 k or report LS393 Q +5 V 3.3 k SD GND Reset +5 V Q SD D CLK Reflex sensor B Q RE 100 15 k 74HCT14 GND B7474 A CLK RV RD CLR QA QB QC QD LS393 Display system B CLK CLR GND Right QA QB QC QD or report LS393 Figure 23. Circuit for objects count and recognition of movement direction www.vishay.com 16 Document Number 80107 02-02 Page 16 Page 17 Vishay Semiconductors VS (+5 V) 82 RA RC 3.3k R1 PNP PNP 4 CK 8 7 RB DIS RQ 6 THR 2 CV TR GND 555 C 100 4 Reflex sensor 3 2 3 1 SD Q 5 CLK D RD Q 6 74HCT74 5 R2 1 100 nF GND Figure 24. Pulse circuit with buffer storage www.vishay.com 17 Document Number 80107 02-02 Page 17 Freescale Semiconductor, Inc. On-Chip Peripheral Systems Page 18 Freescale Semiconductor, Inc... A Practical Motor Control Example In this section, we will develop a practical application by expanding some of the software developed in this book. The example will add some external hardware to the MC68HC705K1 so that we can observe the effects of our software on the world outside the microcontroller. We will use a slightly modified version of the PWM routine that was developed in this chapter to control the speed of a small permanent-magnet direct current (DC) motor. In addition, we will use the concepts developed in the chapter titled On-Chip Peripheral Systems that allow the CPU to read the state of switches connected to the MCU’s general-purpose I/O pins. Theory DC motors are often the best choice for variable-speed motor applications. Brush DC motors are the easiest to control electronically. Electronic control of brushless DC, stepper, AC induction, and switched reluctance motors all require more-complex control circuits in addition to more power-switching devices. Small, low-cost brush DC motors are available off the shelf for many low-volume applications where custom designs would be too expensive. The reliability of brush motors is adequate for most applications. However, eventually, the brushes will wear out and need to be replaced. To vary the speed of a brush DC motor, we must vary the voltage that is applied to the motor. Several approaches can be used to accomplish this. We will examine several of the methods, explaining the major advantages and disadvantages of each. The first and most obvious approach to varying the voltage applied to a motor might be to place a variable resistor in series with the motor and the power source, as shown in Figure 47. While this approach is very simple, it has some serious disadvantages. First, the resistor’s power dissipation capabilities must be matched to the power requirements of the motor. For very small fractional-horsepower DC motors, the size of the variable resistor will be quite modest. However, as the size of the motor increases, the motor’s power requirement increases and the size and cost of the variable resistor will increase. M68HC05 Family — Understanding Small Microcontrollers — Rev. 2.0 198 On-Chip Peripheral Page 18 Systems For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Page 19 On-Chip Peripheral Systems A Practical Motor Control Example M MOTOR Figure 47. Motor Speed Controlled by a Variable Resistor Freescale Semiconductor, Inc... The second major disadvantage of this type of speed control is the inability to automatically adjust the speed of the motor to compensate for varying loads. This is a primary disadvantage for applications that require precise speed control under varying mechanical loads. An electronic variation of the variable resistor form of speed control is shown in Figure 48. In this arrangement, we have replaced the variable resistor with a transistor. Here, the transistor is operated in its linear mode. When a transistor operates in this mode, it essentially behaves as an electrically controlled variable resistor. By applying a proportional analog control signal to the transistor, the "resistivity" of the transistor can be varied, which will in turn vary the speed of the motor. By using a transistor to control the speed of the motor in this manner, the magnitude of the control signal is reduced to much lower voltage and current levels that can be readily generated by electronic circuity. M MOTOR RB VBB Figure 48. Motor Speed Controlled by a Transistor Unfortunately, using a transistor in its linear mode still retains a major disadvantage of using a variable resistor. Like a variable resistor, a M68HC05 Family — Understanding Small Microcontrollers — Rev. 2.0 MOTOROLA On-Chip Peripheral Page 19 Systems For More Information On This Product, Go to: www.freescale.com 199 Freescale Semiconductor, Inc. Page 20 On-Chip Peripheral Systems power transistor operating in its linear region will have to dissipate large amounts of power under varying speed and load conditions. Even though power transistors capable of handling high power levels are widely available at relatively modest prices, the power dissipated by the transistor will usually require a large heat sink to prevent the device from destroying itself. Freescale Semiconductor, Inc... In addition to being operated as a linear device, transistors also may be operated as electronic switches. By applying the proper control signal to a transistor, the device will either be turned on or turned off. As shown in Figure 49, when the transistor is turned on, it will essentially behave as a mechanical switch allowing electric current to pass through it and its load virtually unimpeded. When turned off, no current passes through the transistor or its load. Because the transistor dissipates very little power when it is fully turned on or saturated, the device operates in an efficient manner. M VCC IC RB VBB M VCC VCE = VCC RB VCE ≅ 0 VOLTS TRANSISTOR “ON” IC = 0 VBB = 0 TRANSISTOR “OFF” Figure 49. Transistor Used as an Electronic Switch It would seem that, when using a transistor to control the speed of a DC motor, we are stuck using the device in its inefficient linear mode if we want a motor to operate at something other than full speed. Fortunately, there is an alternative method of controlling the speed of a DC motor using a transistor. By using the transistor as an electronically controlled switch and applying a PWM control signal of sufficient frequency, we can control the speed of the motor. To help understand how turning a motor M68HC05 Family — Understanding Small Microcontrollers — Rev. 2.0 200 On-Chip Peripheral Page 20 Systems For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Page 21 On-Chip Peripheral Systems A Practical Motor Control Example fully on and then fully off can control its speed, consider the PWM waveforms in Figure 50. T1 T2 +5 VOLTS 0 VOLTS Freescale Semiconductor, Inc... a) DUTY CYCLE = T2/T1 = 50% T1 T2 +5 VOLTS 0 VOLTS b) DUTY CYCLE = T2/T1 = 80% Figure 50. PWM Waveforms with 50 and 80 Percent Duty Cycles Figure 50(a) shows a single cycle of a 50 percent duty cycle PWM waveform that is 5 volts during the first half of its period and at 0 volts during the second half. If we integrate (or average) the voltage of the PWM waveform in Figure 50(a) over its period, T1, the average DC voltage is 50 percent of 5 volts or 2.5 volts. Correspondingly, the average DC voltage of the PWM waveform in Figure 50(b), which has a duty cycle of 80 percent, is 80 percent of 5 volts or 4.5 volts. By using a PWM singal to switch a motor on and off in this manner, it will produce the same effect as applying a continuous or average DC voltage at varying levels to the motor. The frequency of the PWM signal must be sufficiently high so that the rotational inertia of the motor integrates the on/off pulses and causes the motor to run smoothly. Motor Control Circuit As mentioned earlier, we will be using a slightly modified version of our PWM routine to control the speed of a small motor. However, before discussing the software involved, we need to take a look at the hardware components required to drive the motor. Figure 51 is a schematic diagram of the power section of our motor control circuit. There are a number of differences between this M68HC05 Family — Understanding Small Microcontrollers — Rev. 2.0 MOTOROLA On-Chip Peripheral Page 21 Systems For More Information On This Product, Go to: www.freescale.com 201 Freescale Semiconductor, Inc. On-Chip Peripheral Systems Page 22 schematic and the conceptual ones used in Figure 48 and Figure 49. We will describe these differences in the following paragraphs. Freescale Semiconductor, Inc... The most noticeable difference is the schematic symbol for the power transistor that will be used as an electronic switch. This device is a power MOSFET. Unlike the bipolar transistor shown in Figure 48 and Figure 49, this special type of transistor is controlled by the magnitude of a voltage applied to its gate. Additionally, this particular power MOSFET, the MTP3055EL, may be completely saturated with only 5 volts applied to its gate. These two characteristics allow this device to be controlled directly by a microcontroller’s output pin for many applications. Because the input iimpedance of a power MOSFET is very high (greater than 40 megaohms), a 10 KΩ resistor is placed between the MOSFET gate and ground to prevent erratic operation of the motor should the connection between the microcontroller and the gate ever become cut. The 15-volt zener diode is placed in parallel with the resistor to protect the gate of the MOSFET from possible damage from high voltage transients that may be generated in the system. The 1N4001 diode in parallel with the motor is used to snub the inductive kick of the motor each time the MOSFET is turned off. The 0.1-µf capacitor in parallel with the motor is used to reduce the electrical noise generated by the motor’s brushes. For further information on designing with power MOSFETs, it is suggested that the reader study the Theory and Applications section of the Motorola Power MOSFET Transistor Data Book (DL153). Figure 52 is a schematic diagram of the microprocessor section of the circuit that we will be using in this example. In addition to generating a PWM output, the MC68HC705K1 is reading three momentary pushbutton switches connected to its I/O pins. As the schematic shows, a single switch turns the motor on and off while two switches set the speed of the motor. M68HC05 Family — Understanding Small Microcontrollers — Rev. 2.0 202 On-Chip Peripheral Page 22 Systems For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Page 23 On-Chip Peripheral Systems A Practical Motor Control Example +5 V 1N4001 M 0.1 F FROM PA7 OF MC68HC705K1 Freescale Semiconductor, Inc... 10 k MTP3055EL 15 V Figure 51. Power Section of the Motor Speed Control Circuit +5 V MC68HC705K1 27 pF 10 k (5) MOTOR CONTROL SWITCHES OSC1 10 M 4 MHz RESET OSC2 27 pF IRQ ON/OFF PA0 SPEED DOWN PA1 SPEED UP PA2 TO GATE OF MTP3055EL PA7 +5 V VSS VDD 0.1 F Figure 52. Microcontroller Section of the Motor Speed Control Circuit M68HC05 Family — Understanding Small Microcontrollers — Rev. 2.0 MOTOROLA On-Chip Peripheral Page 23 Systems For More Information On This Product, Go to: www.freescale.com 203 Freescale Semiconductor, Inc. On-Chip Peripheral Systems Page 24 Freescale Semiconductor, Inc... One side of each switch is connected to circuit ground, while the other side of the switch is connected to an I/O pin on the MC68HC705K1 microcontroller. Each of the input pins on the microcontroller is "pulled up" through a 10-kΩ resistor to +5 volts. These 10-kΩ pullup resistors keep each of the three input pins at a logic 1 when the pushbutton switches are not pressed. In this exampel circuit, the switch controls will operate in the following manner. The motor on/off switch operates as an alternate-action control. Each time the switch is pushed and released, the motor will alternately be turned on or off. When the motor is turned on, its speed will be set to the speed it was going the last time the motor was on. The speed up and speed down switches increase or decrease motor speed, respectively. To increase or decrease the speed of the motor, the respective switch must be pressed and held. The motor speed PWM will be increased or decreased at a rate of approximately 0.4 percent every 24 ms. This "ramp" rate will allow the motor speed to be adjusted across its entire speed range in approximately six seconds. Motor Control Software Figure 53 shows a flowchart that describes the new RTI interrupt software. The only functional change to the PWM routine developed earlier in this chapter is the addition of one instruction at the beginning of the RTI interrupt service routine. This instruction decrements the variable RTIDlyCnt. This variable is used by the three routines that read the input switches to develop a switch debounce delay. As mentioned in the Programming chapter, there are usually many ways to perform a specific task using the microcontroller’s instruction set. To demonstrate this, one part of the revised RTI interrupt routine has been impmlemented in a slightly different manner. Remember, looking at Listing 6. Speed Control Program Listing, that we had to split the variable DesiredPWM into two parts, PWMFine and PWMCoarse. To do this, we used a combination of shifts and rotates to place the upper four bits of the A accumulator (DesiredPWM) into the lower four bits of the X register (PWMCoarse) and the lower four bits of A into the upper four bits of A (PWMFine). This method required nine bytes of program memory and 26 CPU cycles. M68HC05 Family — Understanding Small Microcontrollers — Rev. 2.0 204 On-Chip Peripheral Page 24 Systems For More Information On This Product, Go to: www.freescale.com MOTOROLA Page 25 $GYDQFHG 3RZHU 026)(7 IRL510A FEATURES BVDSS = 100 V ♦ Logic-Level Gate Drive ♦ Avalanche Rugged Technology RDS(on) = 0.44Ω ♦ Rugged Gate Oxide Technology ♦ Lower Input Capacitance ID = 5.6 A ♦ Improved Gate Charge ♦ Extended Safe Operating Area TO-220 ♦ Lower Leakage Current: 10µA (Max.) @ VDS = 100V ♦ Lower RDS(ON): 0.336Ω (Typ.) 1 2 3 1.Gate 2. Drain 3. Source Absolute Maximum Ratings Symbol VDSS ID Value Units Drain-to-Source Voltage Characteristic 100 V Continuous Drain Current (TC=25°C) 5.6 Continuous Drain Current (TC=100°C) 4.0 A IDM Drain Current-Pulsed VGS Gate-to-Source Voltage ±20 V EAS Single Pulsed Avalanche Energy (2) 62 mJ A (1) A 20 IAR Avalanche Current (1) 5.6 EAR Repetitive Avalanche Energy (1) 3.7 mJ dv/dt Peak Diode Recovery dv/dt (3) 6.5 V/ns 37 W PD TJ , TSTG TL Total Power Dissipation (TC=25°C) Linear Derating Factor °C 0.25 Operating Junction and - 55 to +175 Storage Temperature Range °C Maximum Lead Temp. for Soldering 300 Purposes, 1/8 from case for 5-seconds Thermal Resistance Symbol Characteristic Typ. Max. RθJC Junction-to-Case -- 4.1 RθCS Case-to-Sink 0.5 -- RθJA Junction-to-Ambient -- 62.5 Units °C/W Rev. B ©1999 Fairchild Semiconductor Corporation Page 25 1 1&+$11(/ 32:(5 026)(7 Page 26 IRL510A Electrical Characteristics (TC=25°C unless otherwise specified) Symbol Characteristic BVDSS Drain-Source Breakdown Voltage 100 -- -- ∆BV/∆TJ Breakdown Voltage Temp. Coeff. -- 0.1 -- IGSS IDSS RDS(on) gfs Gate Threshold Voltage See Fig 7 VDS=5V,ID=250µA -- 2.0 -- 100 Gate-Source Leakage , Reverse -- -- -100 -- -- 10 -- -- 100 VDS=100V µA V =80V,T =150°C DS C -- -- 0.44 Ω VGS=5V,ID=2.8A (4) VDS=40V,ID=2.8A (4) Drain-to-Source Leakage Current Static Drain-Source On-State Resistance 3.2 -- Input Capacitance -- 180 235 Coss Output Capacitance -- 50 65 Crss Reverse Transfer Capacitance -- 20 25 td(on) Turn-On Delay Time -- 8 25 Rise Time -- 10 30 Turn-Off Delay Time -- 17 45 Fall Time -- 8 25 5.5 8 Qg V -- -- tf V/°C ID=250µA 1.0 Forward Transconductance td(off) VGS=0V,ID=250µA Gate-Source Leakage , Forward Ciss tr V Test Condition Ω VGS(th) Min. Typ. Max. Units Total Gate Charge -- Qgs Gate-Source Charge -- 0.9 -- Qgd Gate-Drain ( Miller ) Charge -- 3.5 -- nA pF VGS=20V VGS=-20V VGS=0V,VDS=25V,f =1MHz See Fig 5 VDD=50V,ID=5.6A, ns RG=12Ω See Fig 13 (4) (5) VDS=80V,VGS=5V, nC ID=5.6A See Fig 6 & Fig 12 (4) (5) Source-Drain Diode Ratings and Characteristics Symbol Characteristic IS Continuous Source Current Min. Typ. Max. Units -- -- 5.6 -- 20 ISM Pulsed-Source Current (1) -- VSD Diode Forward Voltage (4) -- -- trr Reverse Recovery Time -- 85 Qrr Reverse Recovery Charge -- 0.23 A Test Condition Integral reverse pn-diode in the MOSFET 1.5 V TJ=25°C, IS=5.6A,VGS=0V -- ns TJ=25°C, IF=5.6A -- µC diF/dt=100A/µs Notes; (1) Repetitive Rating: Pulse Width Limited by Maximum Junction Temperature (2) L=3mH, IAS=5.6A, VDD=25V, RG=27Ω, Starting TJ =25°C (3) ISD ≤ 5.6A, di/dt ≤ 250A/µs, VDD ≤ BVDSS, Starting TJ =25°C (4) Pulse Test: Pulse Width = 250µs, Duty Cycle ≤ 2% (5) Essentially Independent of Operating Temperature Page 26 2 Page 27 1&+$11(/ 32:(5 026)(7 IRL510A Fig 1. Output Characteristics Fig 2. Transfer Characteristics VGS Top : 7.0 V 6.0 V 5.5 V 5.0 V 4.5 V 4.0 V 3.5 V Bottom : 3.0 V 100 @ Notes : 1. 250 µs Pulse Test 2. TC = 25 oC 10-1 -1 10 0.8 RDS(on) , [ Ω ] Drain-Source On-Resistance ID , Drain Current [A] 101 100 175 oC 100 25 oC @ Notes : 1. VGS = 0 V 2. VDS = 40 V 3. 250 µs Pulse Test - 55 oC 10-1 101 0 2 4 6 8 10 VDS , Drain-Source Voltage [V] VGS , Gate-Source Voltage [V] Fig 3. On-Resistance vs. Drain Current Fig 4. Source-Drain Diode Forward Voltage IDR , Reverse Drain Current [A] ID , Drain Current [A] 101 VGS = 5 V 0.6 0.4 VGS = 10 V 0.2 @ Note : TJ = 25 oC 101 100 @ Notes : 1. VGS = 0 V 2. 250 µs Pulse Test 175 oC 25 oC -1 0.0 0 5 10 15 20 10 0.4 ID , Drain Current [A] 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 VSD , Source-Drain Voltage [V] Fig 5. Capacitance vs. Drain-Source Voltage Fig 6. Gate Charge vs. Gate-Source Voltage 350 Capacitance [pF] 280 C iss 210 C oss 140 @ Notes : 1. VGS = 0 V 2. f = 1 MHz C rss 70 0 100 6 VGS , Gate-Source Voltage [V] Ciss= Cgs+ Cgd ( Cds= shorted ) Coss= Cds+ Cgd Crss= Cgd VDS = 20 V VDS = 50 V VDS = 80 V 4 2 @ Notes : ID = 5.6 A 0 0 101 2 4 6 QG , Total Gate Charge [nC] VDS , Drain-Source Voltage [V] Page 27 3 Page 28 1&+$11(/ 32:(5 026)(7 IRL510A Fig 7. Breakdown Voltage vs. Temperature Fig 8. On-Resistance vs. Temperature 3.0 1.1 1.0 0.9 2.5 RDS(on) , (Normalized) Drain-Source On-Resistance BVDSS , (Normalized) Drain-Source Breakdown Voltage 1.2 @ Notes : 1. VGS = 0 V 2.0 1.5 1.0 2. ID = 250 µA 0.8 -75 -50 -25 0 25 50 75 100 125 150 175 0.0 -75 200 -25 0 25 50 75 100 125 150 175 200 TJ , Junction Temperature [oC] Fig 9. Max. Safe Operating Area Fig 10. Max. Drain Current vs. Case Temperature 6 ID , Drain Current [A] Operation in This Area is Limited by R DS(on) 100 µs 101 1 ms 10 ms DC 100 -50 TJ , Junction Temperature [oC] 102 @ Notes : 1. TC = 25 oC 2. TJ = 175 oC 5 4 3 2 1 3. Single Pulse 10-1 0 10 101 0 25 102 50 75 100 125 150 175 T , Case Temperature [oC] VDS , Drain-Source Voltage [V] c Thermal Response Fig 11. Thermal Response D=0.5 0 10 10- 1 0.2 0.1 @ Notes : 1. Z J C (t)=4.1 o C/W Max. 0.05 2. Duty Factor, D=t /t 0.02 3. TJ M -TC =PD M *Z θ 1 θ JC 2 (t) PDM 0.01 t1 single pulse θJC Z (t) , ID , Drain Current [A] @ Notes : 1. VGS = 5 V 2. ID = 2.8 A 0.5 t2 10- 5 10- 4 t 1 10- 3 10- 2 10- 1 , Square Wave Pulse Duration Page 28 100 101 [sec] 4 Page 29 1&+$11(/ 32:(5 026)(7 IRL510A Fig 12. Gate Charge Test Circuit & Waveform Current Regulator VGS Same Type as DUT 50kΩ Qg 200nF 12V 5V 300nF VDS Qgs VGS Qgd DUT 3mA R1 R2 Current Sampling (IG) Resistor Charge Current Sampling (ID) Resistor Fig 13. Resistive Switching Test Circuit & Waveforms RL Vout Vout 90% VDD Vin ( 0.5 rated VDS ) RG DUT Vin 10% 5V tr td(on) td(off) t on tf t off Fig 14. Unclamped Inductive Switching Test Circuit & Waveforms BVDSS 1 EAS = ---- LL IAS2 -------------------2 BVDSS -- VDD LL VDS Vary tp to obtain required peak ID BVDSS IAS ID RG C ID (t) VDD DUT VDS (t) VDD 5V tp tp Page 29 Time 5 Page 30 1&+$11(/ 32:(5 026)(7 IRL510A Fig 15. Peak Diode Recovery dv/dt Test Circuit & Waveforms DUT + VDS -- IS L Driver VGS RG VGS VGS ( Driver ) Same Type as DUT VDD dv/dt controlled by RG IS controlled by Duty Factor D Gate Pulse Width D = -------------------------Gate Pulse Period 5V IFM , Body Diode Forward Current IS ( DUT ) di/dt IRM Body Diode Reverse Current VDS ( DUT ) Body Diode Recovery dv/dt Vf VDD Body Diode Forward Voltage Drop Page 30 6 Page 31 L7800 SERIES POSITIVE VOLTAGE REGULATORS ■ ■ ■ ■ ■ OUTPUT CURRENT TO 1.5A OUTPUT VOLTAGES OF 5; 5.2; 6; 8; 8.5; 9; 12; 15; 18; 24V THERMAL OVERLOAD PROTECTION SHORT CIRCUIT PROTECTION OUTPUT TRANSITION SOA PROTECTION DESCRIPTION The L7800 series of three-terminal positive regulators is available in TO-220, TO-220FP, TO-220FM, TO-3 and D2PAK packages and several fixed output voltages, making it useful in a wide range of applications. These regulators can provide local on-card regulation, eliminating the distribution problems associated with single point regulation. Each type employs internal current limiting, thermal shut-down and safe area protection, making it essentially indestructible. If adequate heat sinking is provided, they can deliver over 1A output current. Although designed primarily as fixed voltage regulators, these devices can be used with external components to obtain adjustable voltage and currents. TO-220 D2PAK TO-220FP TO-220FM TO-3 SCHEMATIC DIAGRAM April 2004 1/33 Page 31 Page 32 L7800 SERIES ABSOLUTE MAXIMUM RATINGS Symbol VI Parameter DC Input Voltage Value for VO= 5 to 18V 35 for VO= 20, 24V 40 Unit V Output Current Internally Limited Ptot Power Dissipation Internally Limited Tstg Storage Temperature Range -65 to 150 °C Top Operating Junction Temperature for L7800 Range for L7800C -55 to 150 0 to 150 °C IO Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. THERMAL DATA Symbol Parameter Rthj-case Thermal Resistance Junction-case Max Rthj-amb Thermal Resistance Junction-ambient Max D2PAK TO-220 3 5 5 62.5 50 60 SCHEMATIC DIAGRAM 2/33 Page 32 TO-220FP TO-220FM TO-3 Unit 5 4 °C/W 60 35 °C/W Page 33 L7800 SERIES CONNECTION DIAGRAM (top view) TO-220 (Any Type) TO-220FP/TO-220FM D2PAK (Any Type) TO-3 ORDERING CODES TYPE L7805 L7805C L7852C L7806 L7806C L7808 L7808C L7885C L7809C L7812 L7812C L7815 L7815C L7818 L7818C L7820 L7820C L7824 L7824C TO-220 (A Type) TO-220 (C Type) L7805CV L7852CV TO-220 (E Type) D2PAK (A Type) (*) D2PAK (C Type) (T & R) TO-220FP TO-220FM L7805C-V L7805CV1 L7805CD2T L7805C-D2TR L7852CD2T L7805CP L7852CP L7805CF L7852CF L7806CV L7806C-V L7806CD2T L7806CP L7806CF L7808CV L7885CV L7809CV L7808C-V L7809C-V L7808CD2T L7885CD2T L7809CD2T L7808CP L7885CP L7809CP L7808CF L7885CF L7809CF L7812CV L7812C-V L7812CD2T L7812CP L7812CF L7815CV L7815C-V L7815CD2T L7815CP L7815CF L7818CV L7818CD2T L7818CP L7818CF L7820CV L7820CD2T L7820CP L7820CF L7824CV L7824CD2T L7824CP L7824CF TO-3 L7805T L7805CT L7852CT L7806T L7806CT L7808T L7808CT L7885CT L7809CT L7812T L7812CT L7815T L7815CT L7818T L7818CT L7820T L7820CT L7824T L7824CT (*) Available in Tape & Reel with the suffix "-TR". 3/33 Page 33 Page 34 L7800 SERIES APPLICATION CIRCUITS TEST CIRCUITS Figure 1 : DC Parameter Figure 2 : Load Regulation 4/33 Page 34 Page 35 L7800 SERIES Figure 3 : Ripple Rejection ELECTRICAL CHARACTERISTICS OF L7805 (refer to the test circuits, TJ = -55 to 150°C, VI = 10V, IO = 500 mA, CI = 0.33 µF, CO = 0.1 µF unless otherwise specified). Symbol Parameter Test Conditions Min. Typ. Max. 4.8 5 5.2 V PO ≤ 15W 4.65 5 5.35 V mV VO Output Voltage TJ = 25°C VO Output Voltage IO = 5 mA to 1 A VI = 8 to 20 V ∆VO(*) Line Regulation VI = 7 to 25 V TJ = 25°C 3 50 VI = 8 to 12 V TJ = 25°C 1 25 IO = 5 mA to 1.5 A TJ = 25°C 100 IO = 250 to 750 mA TJ = 25°C 25 ∆VO(*) Id ∆Id Load Regulation SVR mV Quiescent Current TJ = 25°C 6 mA Quiescent Current Change IO = 5 mA to 1 A 0.5 mA VI = 8 to 25 V 0.8 ∆VO/∆T Output Voltage Drift eN Unit IO = 5 mA 0.6 Output Noise Voltage B =10Hz to 100KHz Supply Voltage Rejection VI = 8 to 18 V Vd Dropout Voltage IO = 1 A RO Output Resistance f = 1 KHz Isc Short Circuit Current VI = 35 V Iscp Short Circuit Peak Current TJ = 25°C TJ = 25°C f = 120Hz mV/°C 40 68 µV/VO dB TJ = 25°C 2 2.5 TJ = 25°C 0.75 1.2 A 2.2 3.3 A 17 1.3 V mΩ (*) Load and line regulation are specified at constant junction temperature. Changes in VO due to heating effects must be taken into account separately. Pulse testing with low duty cycle is used. 5/33 Page 35 Page 36 L7800 SERIES Figure 4 : Dropout Voltage vs Junction Temperature Figure 7 : Output Voltage vs Junction Temperature Figure 5 : Peak Output Current vs Input/output Differential Voltage Figure 8 : Output Impedance vs Frequency Figure 6 : Supply Voltage Rejection vs Frequency Figure 9 : Quiescent Current vs Junction Temperature 15/33 Page 36 Page 37 L7800 SERIES Figure 10 : Load Transient Response Figure 12 : Quiescent Current vs Input Voltage Figure 11 : Line Transient Response Figure 13 : Fixed Output Regulator NOTE: 1. To specify an output voltage, substitute voltage value for "XX". 2. Although no output capacitor is need for stability, it does improve transient response. 3. Required if regulator is locate an appreciable distance from power supply filter. 16/33 Page 37 Page 38 L7800 SERIES Figure 14 : Current Regulator Vxx IO = + Id R1 Figure 15 : Circuit for Increasing Output Voltage IR1 ≥ 5 Id R2 VO = VXX (1+ ) + Id R2 R1 Figure 16 : Adjustable Output Regulator (7 to 30V) 17/33 Page 38 Page 39 L7800 SERIES Figure 17 : 0.5 to 10V Regulator R4 VO = V xx R1 Figure 18 : High Current Voltage Regulator VBEQ1 R1 = IQ1 IREQ - βQ1 VBEQ1 IO = IREG + Q1 (IREG ) R1 Figure 19 : High Output Current with Short Circuit Protection VBEQ2 RSC = ISC 18/33 Page 39 Page 40 L7800 SERIES Figure 20 : Tracking Voltage Regulator Figure 21 : Split Power Supply (± 15V - 1 A) * Against potential latch-up problems. Figure 22 : Negative Output Voltage Circuit 19/33 Page 40 Page 41 L7800 SERIES Figure 23 : Switching Regulator Figure 24 : High Input Voltage Circuit VIN = VI - (VZ + VBE) Figure 25 : High Input Voltage Circuit Figure 26 : High Output Voltage Regulator 20/33 Page 41 Page 42 L7800 SERIES Figure 27 : High Input and Output Voltage VO = VXX + VZ1 Figure 28 : Reducing Power Dissipation with Dropping Resistor VI(min) - VXX - VDROP(max) R = IO(max) + Id(max) Figure 29 : Remote Shutdown 21/33 Page 42 Page 43 L7800 SERIES Figure 30 : Power AM Modulator (unity voltage gain, IO ≤ 0.5) NOTE: The circuit performs well up to 100 KHz. Figure 31 : Adjustable Output Voltage with Temperature Compensation R2 VO = VXX (1+ ) + V BE R1 NOTE: Q2 is connected as a diode in order to compensate the variation of the Q1 VBE with the temperature. C allows a slow rise time of the VO. Figure 32 : Light Controllers (VOmin = VXX + VBE) VO rises when the light goes up VO falls when the light goes up 22/33 Page 43 Page 44 L7800 SERIES Figure 33 : Protection against Input Short-Circuit with High Capacitance Loads Application with high capacitance loads and an output voltage greater than 6 volts need an external diode (see fig. 33) to protect the device against input short circuit. In this case the input voltage falls rapidly while the output voltage decrease slowly. The capacitance discharges by means of the Base-Emitter junction of the series pass transistor in the regulator. If the energy is sufficiently high, the transistor may be destroyed. The external diode by-passes the current from the IC to ground. 23/33 Page 44