LT1055/LT1056 Precision, High Speed, JFET Input Operational
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LT1055/LT1056 Precision, High Speed, JFET Input Operational Amplifiers U DESCRIPTIO FEATURES ■ ■ ■ ■ The LT®1055/LT1056 JFET input operational amplifiers combine precision specifications with high speed performance. Guaranteed Offset Voltage: 150µV Max –55°C to 125°C: 500µV Max Guaranteed Drift: 4µV/°C Max Guaranteed Bias Current 70°C: 150pA Max 125°C: 2.5nA Max Guaranteed Slew Rate: 12V/µs Min For the first time, 16V/µs slew rate and 6.5MHz gain bandwidth product are simultaneously achieved with offset voltage of typically 50µV, 1.2µV/°C drift, bias currents of 40pA at 70°C and 500pA at 125°C. U APPLICATIO S ■ ■ ■ ■ ■ ■ ■ The 150µV maximum offset voltage specification is the best available on any JFET input operational amplifier. Precision, High Speed Instrumentation Logarithmic Amplifiers D/A Output Amplifiers Photodiode Amplifiers Voltage-to-Frequency Converters Frequency-to-Voltage Converters Fast, Precision Sample-and-Hold The LT1055 and LT1056 are differentiated by their operating currents. The lower power dissipation LT1055 achieves lower bias and offset currents and offset voltage. The additional power dissipation of the LT1056 permits higher slew rate, bandwidth and faster settling time with a slight sacrifice in DC performance. The voltage-to-frequency converter shown below is one of the many applications which utilize both the precision and high speed of the LT1055/LT1056. For a JFET input op amp with 23V/µs guaranteed slew rate, refer to the LT1022 data sheet. , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATIO 0kHz to 10kHz Voltage-to-Frequency Converter 4.7k Distribution of Input Offset Voltage (H Package) 3M 15V 140 0.001 (POLYSTYRENE) 0V TO 10V INPUT 10kHZ TRIM 5k 2 0.1µF 22k 15V 7 + 6 LT1056 3 – 1.5k OUTPUT 1Hz TO 10kHz 0.005% LINEARITY 4 –15V 33pF 3.3M –15V 50% TO ±60µV 100 80 60 40 20 0.1µF = 1N4148 VS = ±15V TA = 25°C 634 UNITS TESTED FROM THREE RUNS LM329 2N3906 *1% FILM NUMBER OF UNITS 120 THE LOW OFFSET VOLTAGE OF LT1056 CONTRIBUTES ONLY 0.1Hz OF ERROR WHILE ITS HIGH SLEW RATE PERMITS 10kHz OPERATION. 0 –400 200 –200 400 0 INPUT OFFSET VOLTAGE (µV) LT1055/56 TA02 LT1055/56 TA01 10556fb 1 LT1055/LT1056 U W W W ABSOLUTE MAXIMUM RATINGS (Note 1) Supply Voltage ...................................................... ±20V Differential Input Voltage ....................................... ±40V Input Voltage ......................................................... ±20V Output Short-Circuit Duration .......................... Indefinite Operating Temperature Range LT1055AM/LT1055M/LT1056AM/ LT1056M (OBSOLETE) .............. –55°C to 125°C LT1055AC/LT1055C/LT1056AC/ LT1056C ................................................ 0°C to 70°C Storage Temperature Range All Devices ...................................... – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C W U U PACKAGE/ORDER INFORMATION ORDER PART NUMBER TOP VIEW BAL 1 8 N/C –IN 2 7 V+ +IN 3 6 OUT V– 4 5 BAL LT1055CN8 LT1056CN8 BAL 1 8 N/C –IN 2 7 V+ +IN 3 6 OUT V– 4 5 BAL S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 130°C/ W TJMAX = 150°C, θJA = 150°C/ W 1055 1056 ORDER PART NUMBER TOP VIEW NC 8 –IN 2 LT1055S8 LT1056S8 S8 PART MARKING N8 PACKAGE 8-LEAD PDIP BALANCE 1 ORDER PART NUMBER TOP VIEW 7 V+ LT1055ACH LT1055CH LT1055AMH LT1055MH 6 OUT 5 BALANCE 4 V– H PACKAGE 8-LEAD TO-5 METAL CAN +IN 3 LT1056ACH LT1056CH LT1056AMH LT1056MH OBSOLETE PACKAGE TJMAX = 150°C, θJA = 150°C/ W, θJC = 45°C/ W Consider the N8 Package for Alternate Source Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS TA = 25°C. VS = ±15V, VCM = 0V unless otherwise noted. LT1055AM/LT1056AM LT1055AC/LT1056AC MIN TYP MAX LT1055M/LT1056M LT1055CH/LT1056CH LT1055CN8/LT1056CN8 MIN TYP MAX SYMBOL PARAMETER CONDITIONS VOS Input Offset Voltage (Note 2) LT1055 H Package LT1056 H Package LT1055 N8 Package LT1056 N8 Package — — — — 50 50 — — 150 180 — — — — — — 70 70 120 140 400 450 700 800 UNITS µV µV µV µV IOS Input Offset Current Fully Warmed Up — 2 10 — 2 20 pA IB Input Bias Current Fully Warmed Up VCM = 10V — — ±10 30 ±50 130 — — ±10 30 ±50 150 pA pA 10556fb 2 LT1055/LT1056 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER TA = 25°C. VS = ±15V, VCM = 0V unless otherwise noted. CONDITIONS Input Resistance:Differential Common Mode VCM = –11V to 8V VCM = 8V to 11V Input Capacitance en LT1055 LT1056 LT1055AM/LT1056AM LT1055AC/LT1056AC MIN TYP MAX LT1055M/LT1056M LT1055CH/LT1056CH LT1055CN8/LT1056CN8 MIN TYP MAX 1012 UNITS — — — — 1012 1011 4 — — — — — — — — 1012 1012 1011 4 — — — — Ω Ω Ω pF — — 1.8 2.5 — — — — 2.0 2.8 — — µVP-P µVP-P — — 28 14 50 20 — — 30 15 60 22 nV/√Hz nV/√Hz Input Noise Voltage 0.1Hz to 10Hz Input Noise Voltage Density f0 = 10Hz (Note 3) f0 = 1kHz (Note 4) In Input Noise Current Density f0 = 10Hz, 1kHz (Note 5) — 1.8 4 — 1.8 4 fA/√Hz AVOL Large-Signal Voltage Gain V0 = ±10V 150 130 400 300 — — 120 100 400 300 — — V/mV V/mV RL = 2k RL = 1k ±11 ±12 — ±11 ±12 — V CMRR Common Mode Rejection Ratio VCM = ±11V 86 100 — 83 98 — dB PSRR Power Supply Rejection Ratio VS = ±10V to ±18V 90 106 — 88 104 — dB VOUT Output Voltage Swing RL = 2k SR Slew Rate GBW Gain Bandwidth Product IS Supply Current Input Voltage Range f = 1MHz ±12 ±13.2 — ±12 ±13.2 — V LT1055 LT1056 10 12 13 16 — — 7.5 9.0 12 14 — — V/µs V/µs LT1055 LT1056 — — 5.0 6.5 — — — — 4.5 5.5 — — MHz MHz LT1055 LT1056 — — 2.8 5.0 4.0 6.5 — — 2.8 5.0 4.0 7.0 mA mA — ±5 — — ±5 — mV Offset Voltage Adjustment Range RPOT = 100k The ● denotes the specifications which apply over the temperature range 0°C ≤ TA ≤ 70°C. VS = ±15V, VCM = 0V unless otherwise noted. MIN LT1055AC LT1056AC TYP MAX LT1055CH/LT1056CH LT1055CN8/LT1056CN8 MIN TYP MAX SYMBOL PARAMETER CONDITIONS UNITS VOS Input Offset Voltage (Note 2) LT1055 H Package LT1056 H Package LT1055 N8 Package LT1056 N8 Package ● ● ● ● — — — — 100 100 — — 330 360 — — — — — — 140 140 250 280 750 800 1250 1350 µV µV µV µV Average Temperature Coefficient of Input Offset Voltage H Package (Note 6) N8 Package (Note 6) ● ● — — 1.2 — 4.0 — — — 1.6 3.0 8.0 12.0 µV/°C µV/°C IOS Input Offset Current Warmed Up TA = 70°C LT1055 LT1056 ● ● — — 10 14 50 70 — — 16 18 80 100 pA pA IB Input Bias Current Warmed Up TA = 70°C LT1055 LT1056 ● ● — — ±30 ±40 ±150 ±80 — — ±40 ±50 ±200 ±240 pA pA AVOL Large-Signal Voltage Gain VO = ±10V, RL = 2k ● 80 250 — 60 250 — V/mV CMRR Common Mode Rejection Ratio VCM = ±10.5V ● 85 100 — 82 98 — dB PSRR Power Supply Rejection Ratio VS = ±10V to ±18V ● 89 105 — 87 103 — dB VOUT Output Voltage Swing RL = 2k ● ±12 ±13.1 — ±12 ±13.1 — V 10556fb 3 LT1055/LT1056 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the temperature range –55°C ≤ TA ≤ 125°C. VS = ±15V, VCM = 0V, unless otherwise noted. SYMBOL PARAMETER VOS MIN LT1055AM LT1056AM TYP MAX ● ● — — 180 180 ● — CONDITIONS Input Offset Voltage (Note 2) LT1055 LT1056 MIN LT1055M LT1056M TYP MAX UNITS 500 550 — — 250 250 1200 1250 µV µV 1.3 4.0 — 1.8 8.0 µV/°C Average Temperature Coefficient of Input Offset Voltage (Note 6) IOS Input Offset Current Warmed Up TA = 125°C LT1055 LT1056 ● ● — — 0.20 0.25 1.2 1.5 — — 0.25 0.30 1.8 2.4 nA nA IB Input Bias Current Warmed Up TA = 125°C LT1055 LT1056 ● ● — — ±0.4 ±0.5 ±2.5 ±3.0 — — ±0.5 ±0.6 ±4.0 ±5.0 nA nA AVOL Large-Signal Voltage Gain VO = ±10V, RL = 2k ● 40 120 — 35 120 — CMRR Common Mode Rejection Ratio VCM = ±10.5V ● 85 100 — 82 98 — dB PSRR Power Supply Rejection Ratio VS = ±10V to ±17V ● 88 104 — 86 102 — dB VOUT Output Voltage Swing RL = 2k ● ±12 ±12.9 — ±12 ±12.9 — V V/mV TA = 25°C. VS = ±15V, VCM = 0V unless otherwise noted. SYMBOL PARAMETER VOS Input Offset Voltage (Note 2) IOS Input Offset Current IB Input Bias Current Input Resistance LT1055CS8/LT1056CS8 MIN TYP MAX CONDITIONS Differential Common Mode 1500 µV Fully Warmed Up 5 30 pA Fully Warmed Up VCM = 10V ±30 30 ±100 150 pA pA VCM = –11V to 8V VCM = 8V to 11V 0.4 0.4 0.05 TΩ TΩ TΩ 4 pF Input Capacitance en UNITS 500 Input Noise Voltage 0.1Hz to 10Hz LT1055 LT1056 Input Noise Voltage Density fO = 10Hz (Note 4) fO = 1kHz (Note 4) in Input Noise Current Density fO = 10Hz, 1kHz (Note 5) AVOL Large-Signal Voltage Gain VO = ±10V RL = 2k RL = 1k Input Voltage Range µVP-P µVP-P 2.5 3.5 35 15 70 22 nV/√Hz nV/√Hz 2.5 10 fA/√Hz 120 100 400 300 V/mV V/mV ±11 ±12 V CMRR Common Mode Rejection Ratio VCM = ±11V 83 98 dB PSRR Power Supply Rejection Ratio VS = ±10V to ±18V 88 104 dB VOUT Output Voltage Swing RL = 2K ±12 ±13.2 V SR Slew Rate 7.5 9.0 12 14 V/µs V/µs GBW Gain Bandwidth Product LT1055 LT1056 4.5 5.5 MHz MHz IS Supply Current LT1055 LT1056 2.8 5.0 Offset Voltage Adjustment Range LT1055 LT1056 f = 1MHz RPOT = 100k ±5 4.0 7.0 mA mA mV 10556fb 4 LT1055/LT1056 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the temperature range 0°C ≤ TA ≤ 70°C. VS = ±15V, VCM = 0V, unless otherwise noted. SYMBOL PARAMETER VOS LT1055CS8/LT1056CS8 MIN TYP MAX CONDITIONS UNITS µV Input Offset Voltage (Note 2) ● 800 2200 Average Temperature Coefficient of Input Offset Voltage ● 4 15 µV/°C 18 150 pA ±60 ±400 IOS Input Offset Current Warmed Up, TA = 70°C ● IB Input Bias Current Warmed Up, TA = 70°C ● AVOL Large-Signal Voltage Gain VO = ±10V, RL = 2k ● 60 250 V/mV CMRR Common Mode Rejection Ratio VCM = ±10.5V ● 82 98 dB pA PSRR Power Supply Rejection Ratio VS = ±10V to ±18V ● 87 103 dB VOUT Output Voltage Swing RL = 2K ● ±12 ±13.1 V For MIL-STD components, please refer to LTC883 data sheet for test listing and parameters. Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Offset voltage is measured under two different conditions: (a) approximately 0.5 seconds after application of power; (b) at TA = 25°C only, with the chip heated to approximately 38°C for the LT1055 and to 45°C for the LT1056, to account for chip temperature rise when the device is fully warmed up. Note 3: 10Hz noise voltage density is sample tested on every lot of A grades. Devices 100% tested at 10Hz are available on request. Note 4: This parameter is tested on a sample basis only. Note 5: Current noise is calculated from the formula: in = (2qlB)1/2, where q = 1.6 • 10 –19 coulomb. The noise of source resistors up to 1GΩ swamps the contribution of current noise. Note 6: Offset voltage drift with temperature is practically unchanged when the offset voltage is trimmed to zero with a 100k potentiometer between the balance terminals and the wiper tied to V+. Devices tested to tighter drift specifications are available on request. 10556fb 5 LT1055/LT1056 U W TYPICAL PERFORMANCE CHARACTERISTICS Input Bias Current Over the Common Mode Range BIAS OR OFFSET CURRENTS MAY BE POSITIVE OR NEGATIVE 100 BIAS CURRENT 30 10 OFFSET CURRENT 3 0 25 75 100 50 AMBIENT TEMPERATURE (°C) 125 1200 VS = ±15V WARMED UP 800 80 TA = 125°C TA = 70°C 40 TA = 25°C 0 A 0 –400 –40 TA = 70°C –80 TA = 125°C –800 B A = POSITIVE INPUT CURRENT B = NEGATIVE INPUT CURRENT B –120 –15 –5 0 5 10 –10 COMMON MODE INPUT VOLTAGE (V) LT1055/56 G01 BATTERY VOLTAGE (V) 120 50% TO ±1.5µV/°C 100 80 60 40 20 50% YIELD TO ±140µV 80 60 40 20 –1200 0 –800 –600 –400 –200 0 200 400 600 800 INPUT OFFSET VOLTAGE (µV) 15 LT1055/56 G03 Long Term Drift of Representative Units Warm-Up Drift 100 50 VS = ±15V TA = 25°C CHANGE IN OFFSET VOLTAGE (µV) VS = ±15V 634 UNITS TESTED FROM THREE RUNS VS = ±15V TA = 25°C 550 UNITS TESTED FROM 120 TWO RUNS (LT1056) 100 140 LT1055/56 G02 Distribution of Offset Voltage Drift with Temperature (H Package)* 140 400 A 160 NUMBER OF INPUTS 300 120 80 60 LT1056CN8 40 LT1055CN8 LT1056 H PACKAGE 20 LT1055 H PACKAGE 0 0 4 6 8 10 –10 –8 –6 –4 –2 0 2 OFFSET VOLTAGE DRIFT WITH TEMPERATURE (µV/°C) VS = ±15V TA = 25°C 40 OFFSET VOLTAGE CHANGE µV) VS = ±15V VCM = 0V WARMED UP Distribution of Input Offset Voltage (N8 Package) INPUT BIAS CURRENT, TA = 125°C (pA) INPUT BIAS AND OFFSET CURRENT (pA) 1000 INPUT BIAS CURRENT, TA = 25°C, TA = 70°C (pA) Input Bias and Offset Currents vs Temperature 30 20 10 0 –10 –20 –30 –40 –50 1 3 4 2 TIME AFTER POWER ON (MINUTES) 0 5 1 0 3 2 TIME (MONTHS) 4 LT1055/56 G05 *DISTRIBUTION IN THE PLASTIC (N8) PACKAGE IS SIGNIFICANTLY WIDER. 5 LT1055/56 GO6 LT1055/56 G04 LT1056 LT1055 0 2 6 4 TIME (SECONDS) 8 10 LT1055/56 GO7 Voltage Noise vs Frequency 100 7 70 PEAK-TO-PEAK NOISE 5 50 3 30 f0 = 10kHz 2 20 f0 = 1kHz 1 10 20 30 50 60 40 CHIP TEMPERATURE (°C) 70 10 80 LT1055/56 G08 1000 RMS NOISE VOLTAGE DENSITY (nV/√Hz) 0.1Hz TO 10Hz PEAK-TO-PEAK NOISE (µV/P-P) Noise vs Chip Temperature 10 RMS NOISE VOLTAGE DENSITY (nV/√Hz) NOISE VOLTAGE (1µV/DIVISION) 0.1Hz to 10Hz Noise VS = ±15V TA = 25°C 300 100 LT1056 1/f CORNER = 28HZ 30 LT1055 1/f CORNER = 20HZ 10 1 3 10 100 30 FREQUENCY (Hz) 300 1000 LT1055/56 G09 10556fb 6 LT1055/LT1056 U W TYPICAL PERFORMANCE CHARACTERISTICS LT1055 Large-Signal Response 20mV/DIV 5V/DIV Small-Signal Response 5V/DIV LT1056 Large-Signal Response AV = 1, CL = 100pF, 0.5µs/DIV AV = 1, CL = 100pF, 0.5µs/DIV LT1055/56 G10 LT1055/56 G12 AV = 1, CL = 100pF, 0.2µs/DIV LT1055/56 G11 Undistorted Output Swing vs Frequency Output Impedence vs Frequency 10 LT1056 GBW SLEW RATE (V/µS) 24 18 LT1056 12 LT1055 GBW 20 6 4 LT1056 SLEW 10 2 LT1055 SLEW 6 VS = ±15V f0 = 1MHz FOR GBW 0 0 0.1 1 FREQUENCY (MHz) –25 10 LT1055/56 G13 20 GAIN (dB) GAIN (dB) LT1056 LT1056 Voltage Gain vs Temperature 120 GAIN 140 LT1055 LT1056 0 20 –10 10 100 1k 10k 100k 1M 10M 100M FREQUENCY (Hz) LT1055/56 G16 1000 1 VS = ±15V VO = ±10V 300 RL = 1k 100 30 160 VS = ±15V TA = 25°C 0 1000 LT1055/56 G15 10 40 1 10 100 FREQUENCY (kHz) 1 PHASE SHIFT (DEGREES) 60 LT1056 AV = 1 PHASE LT1055 80 LT1055 RL = 2k 100 –20 1 LT1056 0.1 100 LT1055 AV = 10 LT1055 Gain, Phase Shift vs Frequency VS = ±15V TA = 25°C 120 LT1056 LT1055/56 G14 Gain vs Frequency 140 AV = 100 LT1055 125 25 75 TEMPERATURE (˚C) VS = ±15V TA = 25°C 10 VOLTAGE GAIN (V/mV) LT1055 8 GAIN BANDWIDTH PRODUCT (MHz) VS = ±15V TA = 25°C 100 OUTPUT IMPEDANCE (Ω) 30 30 PEAK-TO-PEAK OUTPUT SWING (V) Slew Rate, Gain Bandwidth vs Temperature 4 2 FREQUENCY (MHz) 6 8 10 LT1055/56 G17 10 –75 25 –25 75 TEMPERATURE (°C) 125 LT1055/56 G18 10556fb 7 LT1055/LT1056 U W TYPICAL PERFORMANCE CHARACTERISTICS LT1055 Settling Time 10 0.5mV 5mV 1mV 0 5mV 2mV –5 10mV 1mV 0.5mV VS = ±15V TA = 25°C 10mV 1 2 0.5mV 5mV 1mV 5mV –5 10mV 3 0.5mV 2mV 1mV 1 0 2 120 100 60 40 20 90 0 125 10 100 1k 10k 100k FREQUENCY (Hz) 1M LT1055/56 G22 25°C 4 TA = 125°C LT1055 25°C 2 TA = – 55°C TA = 125°C ±10 ±15 ±5 SUPPLY VOLTAGE (V) ±20 LT1055/56 G25 40 20 100 100k 10k 1k FREQUENCY (Hz) 50 TA = –25°C TA = –125°C VS = ±15V –3 TA = –25°C –9 –15 0.1 TA = – 55°C 40 0 –6 10M LT1055/56 G24 TA = –55°C 6 3 1M Short-Circuit Current vs Time 9 –12 0 NEGATIVE SUPPLY 60 10 SHORT-CIRCUIT CURRENT (mA) OUTPUT VOLTAGE SWING (V) SUPPLY CURRENT (mA) 12 TA = – 55°C POSITIVE SUPPLY 80 0 10M 15 LT1056 100 Output Swing vs Load Resistance 8 6 TA = 25°C 120 LT1055/56 G23 Supply Current vs Supply Voltage 0 LT1055/56 G21 140 80 CMRR (dB) CMRR, PSRR (dB) 110 100 Power Supply Rejection Ratio vs Frequency VS = ±15V TA = 25°C 100 25 75 TEMPERATURE (˚C) –12 Common Mode Rejection Ratio vs Frequency VS = ±10V TO ±17V FOR PSRR VS = ±15V, VCM = ±10.5V FOR CMRR –25 ≈ –11 LT1055/56 G20 Common Mode and Power Supply Rejections vs Temperature CMRR ≈ ±10 –14 VS = ±15V –15 50 –50 0 TEMPERATURE (°C) 3 LT1055/56 G19 PSRR 12 11 –13 SETTLING TIME (µS) SETTLING TIME (µS) 120 13 VS = ±15V TA = 25°C 0 –10 0 2mV 5 POWER SUPPLY REJECTION RATIO (dB) 10mV 5 15 14 BATTERY VOLTAGE (V) 2mV OUTPUT VOLTAGE SWING FROM 0V (V) OUTPUT VOLTAGE SWING FROM 0V (V) 10 –10 Common Mode Range vs Temperature LT1056 Settling Time TA = –125°C TA = –55°C TA = 25°C 30 TA = 125°C 20 10 VS = ±15V 0 –10 SINKING –20 TA = 125°C –30 TA = 25°C –40 TA = – 55°C –50 0.3 1 3 LOAD RESISTANCE (kΩ) 10 LT1055/56 G26 0 2 1 3 TIME FROM OUTPUT SHORT TO GROUND (MINUTES) LT1055/56 G27 10556fb 8 LT1055/LT1056 U U W U APPLICATIONS INFORMATION The LT1055/LT1056 may be inserted directly into LF155A/ LT355A, LF156A/LT356A, OP-15 and OP-16 sockets. Offset nulling will be compatible with these devices with the wiper of the potentiometer tied to the positive supply. N/C OFFSET TRIM V+ 7 OUTPUT Offset Nulling 8 1 6 V+ 3 5 – LT1055 LT1056 + 6 V– GUARD LT1055/56 AI2 LT1055/56 AI1 No appreciable change in offset voltage drift with temperature will occur when the device is nulled with a potentiometer, RP, ranging from 10k to 200k. The LT1055/LT1056 can also be used in LF351, LF411, AD547, AD611, OPA-111, and TL081 sockets, provided that the nulling cicuitry is removed. Because of the LT1055/ LT1056’s low offset voltage, nulling will not be necessary in most applications. Achieving Picoampere/Microvolt Performance In order to realize the picoampere-microvolt level accuracy of the LT1055/LT1056 proper care must be exercised. For example, leakage currents in circuitry external to the op amp can significantly degrade performance. High quality insulation should be used (e.g. Teflon™, Kel-F); cleaning of all insulating surfaces to remove fluxes and other residues will probably be required. Surface coating may be necessary to provide a moisture barrier in high humidity environments. Board leakage can be minimized by encircling the input circuitry with a guard ring operated at a potential close to that of the inputs: in inverting configurations the guard ring should be tied to ground, in noninverting connnections to the inverting input at pin 2. Guarding both sides of the printed circuit board is required. Bulk leakage reduction depends on the guard ring width. Teflon is a trademark of Dupont. 3 OUT 4 V– 4 7 IN PU TS 2 2 5 OFFSET TRIM 1 RP The LT1055/LT1056 has the lowest offset voltage of any JFET input op amp available today. However, the offset voltage and its drift with time and temperature are still not as good as on the best bipolar amplifiers because the transconductance of FETs is considerably lower than that of bipolar transistors. Conversely, this lower transconductance is the main cause of the significantly faster speed performance of FET input op amps. Offset voltage also changes somewhat with temperature cycling. The AM grades show a typical 20µV hysteresis (30µV on the M grades) when cycled over the –55°C to 125°C temperature range. Temperature cycling from 0°C to 70°C has a negligible (less than 10µV) hysteresis effect. The offset voltage and drift performance are also affected by packaging. In the plastic N8 package the molding compound is in direct contact with the chip, exerting pressure on the surface. While NPN input transistors are largely unaffected by this pressure, JFET device matching and drift are degraded. Consequently, for best DC performance, as shown in the typical performance distribution plots, the TO-5 H package is recommended. Noise Performance The current noise of the LT1055/LT1056 is practically immeasurable at 1.8fA/√Hz. At 25°C it is negligible up to 1G of source resistance, RS (compound to the noise of RS). Even at 125°C it is negligible to 100M of RS. 10556fb 9 LT1055/LT1056 U W U U APPLICATIONS INFORMATION The voltage noise spectrum is characterized by a low 1/f corner in the 20Hz to 30Hz range, significantly lower than on other competitive JFET input op amps. Of particular interest is the fact that with any JFET IC amplifier, the frequency location of the 1/f corner is proportional to the square root of the internal gate leakage currents and, therefore, noise doubles every 20°C. Furthermore, as illustrated in the noise versus chip temperature curves, the 0.1Hz to 10Hz peak-to-peak noise is a strong function of temperature, while wideband noise (f0 = 1kHz) is practically unaffected by temperature. Consequently, for optimum low frequency noise, chip temperature should be minimized. For example, operating an LT1056 at ±5V supplies or with a 20°C/W case-toambient heat sink reduces 0.1Hz to 10Hz noise from typically 2.5µVP-P (±15V, free-air) to 1.5µVP-P. Similiarly, the noise of an LT1055 will be 1.8µVP-P typically because of its lower power dissipation and chip temperature. capacitance is isolated from the “false summing” node, and (2) it does not require a “flat top” input pulse since the input pulse is merely used to steer current through the diode bridges. For more details, please see Application Note 10. As with most high speed amplifiers, care should be taken with supply decoupling, lead dress and component placement. When the feedback around the op amp is resistive (RF), a pole will be created with RF, the source resistance and capacitance (RS, CS), and the amplifier input capacitance (CIN ≈ 4pF). In low closed-loop gain configurations and with RS and RF in the kilohm range, this pole can create excess phase shift and even oscillation. A small capacitor (CF) in parallel with RF eliminates this problem. With RS (CS + CIN) = RFCF, the effect of the feedback pole is completely removed. CF High Speed Operation RF Settling time is measured in the test circuit shown. This test configuration has two features which eliminate problems common to settling time measurments: (1) probe – RS CIN CS OUTPUT + LT1055/56 AI03 Settling Time Test Circuit 15V 0.01 DISC + 15k 10pF (TYPICAL) 10µF SOLID TANTALUM 10k – –15V 15k 0.01 DISC + 2k 50Ω 2W 15V + 10µF SOLID TANTALUM 2k + PULSE GEN INPUT (5V MIN STEP) 10µF SOLID TANTALUM 15k 0.01 DISC LT1055 LT1056 AUT OUTPUT 4.7k + AMPLIFIER UNDER TEST 10k 2N3866 15V HP5082-8210 HEWLETT PACKARD 1/2 U440 50Ω 2N160 3Ω –15V OUTPUT TO SCOPE 15V 1/2 U440 –15V 100Ω DC ZERO 15k + 0.01 DISC 15V 10µF SOLID TANTALUM = 1N4148 –15V 3Ω 2N3866 2N5160 4.7k –15V LT1055/56 AI04 10556fb 10 LT1055/LT1056 U U W U APPLICATIONS INFORMATION Voltage Follower with Input Exceeding the Negative Common Mode Range Phase Reversal Protection Most industry standard JFET input op amps (e.g., LF155/ LF156, LF351, LF411, OP15/16) exhibit phase reversal at the output when the negitive common mode limit at the input is exceeded (i.e., from –12V to –15V with ±15V supplies). This can cause lock-up in servo systems. As shown below, the LT1055/LT1056 does not have this problem due to unique phase reversal protection circuitry (Q1 on simplified schematic). 15V 2 7 – LT1055/56 INPUT ±15V SINE WAVE 3 + 4 2k LT1055/56 AI05 Output LT1055/LT1056 10V/DIV 10V/DIV 10V/DIV OUTPUT –15V Output (LF155/LF56, LF441, OP-15/OP-16) Input 6 0.5ms/DIV 0.5ms/DIV 0.5ms/DIV LT1055/56 AI06 LT1055/56 AI07 LT1055/56 AI08 U TYPICAL APPLICATIONS † Exponential Voltage-to-Frequency Converter for Music Synthesizers INPUT 0V TO 10V EXPONENT TRIM 2500Ω* 11.3k* 500pF POLYSTYRENE 15V 5 6 3.57k* ZERO TRIM 4 2 2N3906 2N3904 7 – 500k 3 + SAWTOOTH OUTPUT –15V 1.1k 4.7k 500Ω* 6 LT1055 1k* 562Ω* 15V LM329 4.7k 10k* 10k* 2 15V 7 – LM301A 1k* 3 1 2 SCALE FACTOR 1V IN OCTAVE OUT *1% METAL FILM RESISTOR PIN NUMBERED TRANSISTORS = CA3096 ARRAY 3 15V 6 1 4 0.01µF 8 13 8 + 9 3k 1N148 14 15 2.2k 7 33Ω –15V †For ten additional applications utilizing the LT1055 and LT1056, please see the LTC1043 data sheet and Application Note 3. TEMPERATURE CONTROL LOOP LT1055/56 TA03 10556fb 11 LT1055/LT1056 U TYPICAL APPLICATIO S 12-Bit Charge Balance A/D Converter 74C00 28k 0.003µF 14k 0.01 2 CLK OUTPUT (B) 15V 7 – 10k 6 LT1055 3 + 10k 2N3904 1N4148 249k* D 4 –15V OUTPUT (A) CLK Q 74C74 Q P CL 1N4148 1N4148 15V 0V TO 10V INPUT 33k LM329 10k 15V COUPLE THERMALLY 6 33k 15V 7 – 2 CIRCUIT OUTPUT fOUT (A) RATIO fCLK (B) LT1001 4 + 3 –15V 1N4148 LT1055/56 TA04 Fast “No Trims” 12-Bit Multiplying CMOS DAC Amplifier Fast, 16-Bit Current Comparator RFEEDBACK REFERENCE IN DELAY = 250ns HP5082-2810 IOUT1 TYPICAL 12-BIT CMOS DAC * = 1% FILM RESISTOR 15V – LT1055 IOUT2 OUTPUT 15V 4.7k 50k* 2 15V – 100k* + INPUT LT1055/56 TA05 3 LT1009 2.5V 7 6 LT1056 + 2 4 3 –15V 3k 8 + 7 LT1011 OUTPUT 1 – 4 –15V LT1055/56 TA06 10556fb 12 LT1055/LT1056 U TYPICAL APPLICATIO S Temperature-to-Frequency Converter 560Ω 1k* 1k* 15V 15V 2N2222 10k 2N2907 6.2k* LM329 0.01µF POLYSTYRENE TTL OUTPUT 0kHz TO 1kHz = 0°C TO 100°C 2.7k 2N2222 2k 100°C ADJ 500Ω 0°C ADJ 510pF 15V 2 6.2k* 3 10k 7 – 6 LT1055 + 820Ω* 4.7k 4 –15V LM134 510Ω 2V 137Ω* *1% FILM RESISTOR LT1055/56 TA07 100kHz Voltage Controlled Oscillator 15V 2 *1% FILM RESISTOR =1N4148 100kHz DISTORTION TRIM 2k 9.09k* 3 22.1k + 2 – –15V 1k 15V 50k 10Hz DISTORTION TRIM –15V 68k FINE DISTORTION TRIMS POLYSTYRENE 500pF 22M 10k 7 6 2N4391 2N4391 5k* + 4 –15V 2.5k* 2 – 2N4391 + –15V GT UP –V +15V SINE OUT 2VRMS 0kHs TO 100kHs –15 10k 22k HP50822810 2 + 1k 8 LT1011 3 – 1k 7 1 4 20pF 10k VR Y1 Y2 10k* 6 4 +V CC W Z1 Z2 15V 15V 7 LT1056 3 X1 X2 U1 U2 AD639 COM 5k FREQUENCY TRIM 68k 15pF –15V LT1056 3 4 4.5k 15V 10k* 6 LT1056 FREQUENCY LINEARITY = 0.1% FREQUENCY STABILITY = 150ppm/°C SETTLING TIME = 1.7µs DISTORTION = 0.25% AT 100kHz, 0.07% AT 10zHz 0V TO 10V INPUT 7 – 0.01µF –15V LM329 4.7k –15V 4.7k 15V LT1055/56 TA08 10556fb 13 LT1055/LT1056 U TYPICAL APPLICATIO S 12-Bit Voltage Output D/A Converter 12-BIT CURRENT OUTPUT D/A CONVERTER (e.g., 6012,565 OR DAC-80) CF 2 0 TO 2 OR 4mA 15V 7 – 6 LT1056 3 + CF = 15pF TO 33pF SETTLING TIME TO 2mV (0.8 LSB) = 1.5µs TO 2µs OUTPUT 0V TO 10V 4 –15V LT1055/56 TA09 W W SI PLIFIED SCHE ATIC NULL 5 7 V+ 7k Q8 7k Q7 NULL 1 J5 J6 J7 –INPUT 2 300Ω 7.5pF Q9 +INPUT 3 J1 J2 Q15 Q12 20Ω Q10 Q11 6 OUTPUT J3 J8 Q2 Q1 Q14 Q13 Q5 8k 200Ω 14k 14k 9pF Q3 120µA* (160) Q4 J4 120µA* (160) 800µA* (1000) 400µA* (1100) Q16 3k 50Ω 4 V– *CURRENTS AS SHOWN FOR LT1055. (X) = CURRENTS FOR LT1056. LT1055/56 SCHM 10556fb 14 LT1055/LT1056 U PACKAGE DESCRIPTIO H Package 8-Lead TO-5 Metal Can (.200 Inch PCD) (Reference LTC DWG # 05-08-1320) 0.335 – 0.370 (8.509 – 9.398) DIA 0.305 – 0.335 (7.747 – 8.509) 0.040 (1.016) MAX 0.050 (1.270) MAX SEATING PLANE 0.165 – 0.185 (4.191 – 4.699) GAUGE PLANE 0.010 – 0.045* (0.254 – 1.143) REFERENCE PLANE 0.500 – 0.750 (12.700 – 19.050) 0.016 – 0.021** (0.406 – 0.533) 0.027 – 0.045 (0.686 – 1.143) 45°TYP PIN 1 0.028 – 0.034 (0.711 – 0.864) 0.200 (5.080) TYP 0.110 – 0.160 (2.794 – 4.064) INSULATING STANDOFF *LEAD DIAMETER IS UNCONTROLLED BETWEEN THE REFERENCE PLANE AND 0.045" BELOW THE REFERENCE PLANE 0.016 – 0.024 **FOR SOLDER DIP LEAD FINISH, LEAD DIAMETER IS (0.406 – 0.610) H8(TO-5) 0.200 PCD 1197 OBSOLETE PACKAGE N8 Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) 0.400* (10.160) MAX 8 7 6 5 1 2 3 4 0.255 ± 0.015* (6.477 ± 0.381) 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.381) ( +0.035 0.325 –0.015 +0.889 8.255 –0.381 ) 0.045 – 0.065 (1.143 – 1.651) 0.130 ± 0.005 (3.302 ± 0.127) 0.065 (1.651) TYP 0.100 (2.54) BSC 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 ± 0.003 (0.457 ± 0.076) N8 1098 *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) 10556fb Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 15 LT1055/LT1056 U TYPICAL APPLICATIO ±120V Output Precision Op Amp 125V 1µF ±25mA OUTPUT HEAT SINK OUTPUT TRANSISTORS 330Ω 510Ω 10k 2N5415 1N965 100pF 10k 2N3440 50k 2 10k – + 1k 2N2222 27Ω 1N4148 7 6 LT1055 3 INPUT 1M OUTPUT 4 27Ω 1N4148 1k 50k 2N2907 1M 2N5415 2N3440 1N965 10k 33pF 100k 510Ω 330Ω 1µF –125V LT1055/56 TA10 U PACKAGE DESCRIPTIO 0.189 – 0.197* (4.801 – 5.004) 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0.053 – 0.069 (1.346 – 1.752) 0°– 8° TYP 0.016 – 0.050 (0.406 – 1.270) 0.014 – 0.019 (0.355 – 0.483) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 8 7 6 5 0.004 – 0.010 (0.101 – 0.254) 0.050 (1.270) BSC 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 1 2 3 4 SO8 1298 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1122 Fast Settling JFET Op Amp 340ns Settling Time, GBW = 14MHz, SR = 60V/µs LT1792 Low Noise JFET Op Amp en = 6nV/√Hz Max at f = 1kHz 10556fb 16 Linear Technology Corporation LT/CPI 0302 1.5K REV B • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 1994 This datasheet has been download from: www.datasheetcatalog.com Datasheets for electronics components.
