®
OPA27
OPA37
OPA
27
OPA
27
Ultra-Low Noise Precision
OPERATIONAL AMPLIFIERS
FEATURES
APPLICATIONS
● LOW NOISE: 4.5nV/√Hz max at 1kHz
● PRECISION INSTRUMENTATION
● LOW OFFSET: 100µV max
● LOW DRIFT: 0.4µV/°C
● DATA ACQUISITION
● TEST EQUIPMENT
● HIGH OPEN-LOOP GAIN: 117dB min
● HIGH COMMON-MODE REJECTION:
100dB min
● PROFESSIONAL AUDIO EQUIPMENT
● TRANSDUCER AMPLIFIER
● RADIATION HARD EQUIPMENT
● HIGH POWER SUPPLY REJECTION:
94dB min
● FITS OP-07, OP-05, AD510, AD517
SOCKETS
7
+VCC
DESCRIPTION
The OPA27/37 is an ultra-low noise, high precision
monolithic operational amplifier.
Laser-trimmed thin-film resistors provide excellent
long-term voltage offset stability and allow superior
voltage offset compared to common zener-zap techniques.
8
Trim
1
Trim
6
A unique bias current cancellation circuit allows bias
and offset current specifications to be met over the full
–55°C to +125°C temperature range.
The OPA27 is internally compensated for unity-gain
stability. The decompensated OPA37 requires a closedloop gain ≥ 5.
Output
2
–In
3
+In
The Burr-Brown OPA27/37 is an improved replacement for the industry-standard OP-27/OP-37.
4
–VCC
International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111
Internet: http://www.burr-brown.com/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132
®
© 1984 Burr-Brown Corporation
SBOS135
PDS-466M
1
OPA27, 37
Printed in U.S.A. March, 1998
SPECIFICATIONS
At VCC = ±15V and TA = +25°C, unless otherwise noted.
OPA27/37G
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
3.8
3.3
3.2
0.09
1.7
1.0
0.4
8.0
5.6
4.5
0.25
0.6
nV/√Hz
nV/√Hz
nV/√Hz
µVp-p
pA/√Hz
pA/√Hz
pA/√Hz
±25
±0.4
0.4
±100
±1.8 (6)
2.0
µV
µV/°C
µV/mo
120
±1
±20
dB
µV/V
BIAS CURRENT
Input Bias Current
±15
±80
nA
OFFSET CURRENT
Input Offset Current
10
75
nA
INPUT NOISE (6)
Voltage, fO = 10Hz
fO = 30Hz
fO = 1kHz
fB = 0.1Hz to 10Hz
Current,(1) fO = 10Hz
fO = 30Hz
fO = 1kHz
VOLTAGE (2)
OFFSET
Input Offset Voltage
Average Drift (3)
Long Term Stability (4)
TA MIN to TA MAX
±VCC = 4 to 18V
±VCC = 4 to 18V
Supply Rejection
94
IMPEDANCE
Common-Mode
VOLTAGE RANGE
Common-Mode Input Range
Common-Mode Rejection
OPEN-LOOP VOLTAGE GAIN, DC
FREQUENCY RESPONSE
Gain-Bandwidth Product (5)
Slew Rate (5)
Settling Time, 0.01%
RATED OUTPUT
Voltage Output
Output Resistance
Short Circuit Current
POWER SUPPLY
Rated Voltage
Voltage Range,
Derated Performance
Current, Quiescent
2 || 2.5
GΩ || pF
±11
100
±12.3
122
V
dB
RL ≥ 2kΩ
RL ≥ 1kΩ
117
124
124
dB
dB
OPA27
OPA37
VO = ±10V,
RL = 2kΩ
OPA27, G = +1
OPA37, G = +5
OPA27, G = +1
OPA37, G = +5
5 (6)
45 (6)
8
63
MHz
MHz
1.7 (6)
11(6)
1.9
11.9
25
25
V/µs
V/µs
µs
µs
±12
±10
±13.8
±12.8
70
25
V
V
Ω
mA
VIN = ±11VDC
RL ≥ 2kΩ
RL ≥ 600Ω
DC, Open Loop
RL = 0Ω
60(6)
±15
±4
IO = 0mADC
3.3
TEMPERATURE RANGE
Specification
Operating
–40
–40
VDC
±22
5.7
VDC
mA
+85
+85
°C
°C
NOTES: (1) Measured with industry-standard noise test circuit (Figures 1 and 2). Due to errors introduced by this method, these current noise specifications should
be used for comparison purposes only. (2) Offset voltage specification are measured with automatic test equipment after approximately 0.5 seconds from power turnon. (3) Unnulled or nulled with 8kΩ to 20kΩ potentiometer. (4) Long-term voltage offset vs time trend line does not include warm-up drift. (5) Typical specification only
on plastic package units. Slew rate varies on all units due to differing test methods. Minimum specification applies to open-loop test. (6) This parameter guaranteed by
design.
®
OPA27, 37
2
SPECIFICATIONS
At VCC = ±15V and TA = +25°C, unless otherwise noted.
OPA27/37G
PARAMETER
INPUT VOLTAGE (1)
Input Offset Voltage
Average Drift (2)
Supply Rejection
CONDITIONS
MIN
TA MIN to TA MAX
±VCC = 4.5 to 18V
±VCC = 4.5 to 18V
90 (3)
TYP
MAX
UNITS
±48
±0.4
±220(3)
±1.8 (3)
µV
µV/°C
122
dB
BIAS CURRENT
Input Bias Current
±21
±150 (3)
nA
OFFSET CURRENT
Input Offset Current
E, F, G
20
135 (3)
nA
VOLTAGE RANGE
Common-Mode Input Range
Common-Mode Rejection
OPEN-LOOP GAIN, DC
Open-Loop Voltage Gain
RATED OUTPUT
Voltage Output
Short Circuit Current
VIN = ±11VDC
±10.5 (3)
96 (3)
±11.8
122
V
dB
RL ≥ 2kΩ
113 (3)
120
dB
RL = 2kΩ
VO = 0VDC
±11.0 (3)
±13.4
25
V
mA
TEMPERATURE RANGE
Specification
–40
°C
+85
NOTES: (1) Offset voltage specification are measured with automatic test equipment after approximately 0.5s from power turn-on. (2) Unnulled or nulled with 8kΩ to
20kΩ potentiometer. (3) This parameter guaranteed by design.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage ................................................................................... ±22V
Internal Power Dissipation (1) ........................................................ 500mW
Input Voltage ...................................................................................... ±VCC
Output Short-Circuit Duration (2) ................................................. Indefinite
Differential Input Voltage (3) ............................................................. ±0.7V
Differential Input Current (3) ........................................................... ±25mA
Storage Temperature Range .......................................... –55°C to +125°C
Operating Temperature Range ......................................... –40°C to +85°C
Lead Temperature:
P (soldering, 10s) ....................................................................... +300°C
U (soldering, 3s) ......................................................................... +260°C
PACKAGE TYPE
θJA
UNITS
8-Pin Plastic DIP (P)
8-Pin SOIC (U)
100
160
°C/W
°C/W
NOTES: (1) Maximum package power dissipation vs ambient temperature. (2) To
common with ±VCC = 15V. (3) The inputs are protected by back-to-back diodes.
Current limiting resistors are not used in order to achieve low noise. If differential
input voltage exceeds ±0.7V, the input current should be limited to 25mA.
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Burr-Brown
recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling
and installation procedures can cause damage.
ESD damage can range from subtle performance degradation
to complete device failure. Precision integrated circuits may
be more susceptible to damage because very small parametric
changes could cause the device not to meet its published
specifications.
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes
no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change
without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant
any BURR-BROWN product for use in life support devices and/or systems.
®
3
OPA27, 37
CONNECTION DIAGRAMS
PACKAGE/ORDERING INFORMATION
Top View
P, U Packages
Offset Trim
1
8
Offset Trim
–In
2
7
+VCC
+In
3
6
Output
–VCC
4
5
NC
PRODUCT(1)
PACKAGE
TEMPERATURE
RANGE (°C)
OPA27GP
OPA27GU(2)
Plastic
SOIC
–40 to +85
–40 to +85
OFFSET
VOLTAGE
MAX (µV), 25°C
PACKAGE
DRAWING
NUMBER(3)
±100
±100
006
182
NOTE: (1) Packages for OPA37 are same as for OPA27. (2) OPA27GU may
be marked OPA27U. Likewise, OPA37GU may be marked OPA37U. (3) For
detailed drawing and dimension table, please see end of data sheet, or
Appendix C of Burr-Brown IC Data Book.
0.1µF
100kΩ
10Ω
2kΩ
DUT
4.3kΩ
4.7µF
Voltage Gain
Total = 50,000
2.2µF
100kΩ
0.1µF
24.3kΩ
NOTE: All capacitor values are for nonpolarized capacitors only.
FIGURE 1. 0.1Hz to 10Hz Noise Test Circuit.
0.1Hz TO 10Hz NOISE
1s/div
40nV/div
FIGURE 2. Low Frequency Noise.
®
OPA27, 37
22µF
OPA111
4
Scope
x1
RIN = 1MΩ
110kΩ
TYPICAL PERFORMANCE CURVES
At TA = +25°C, ±VCC = ±15VDC, unless otherwise noted.
INPUT OFFSET VOLTAGE CHANGE
DUE TO THERMAL SHOCK
INPUT OFFSET VOLTAGE WARM-UP DRIFT
+20
Offset Voltage Change (µV)
Offset Voltage Change (µV)
+10
+5
G
0
–5
+10
+25°C
0
TA = +25°C to TA = +70°C
Fluid Bath
+70°C
–10
TO-99
–10
–20
0
1
2
3
4
5
6
–1
+1
+2
+3
+4
+5
Time From Thermal Shock (min)
INPUT VOLTAGE NOISE vs NOISE BANDWIDTH
(0.1Hz to Indicated Frequency)
TOTAL INPUT VOLTAGE NOISE SPECTRAL DENSITY
vs SOURCE RESISTANCE
100
80
60
Voltage Noise (nV/√Hz)
10
Voltage Noise (µVrms)
0
Time From Power Turn-On (min)
1
0.1
RS = 0 Ω
R1
-
40
+
20
10
8
6
4
R1
RSOURCE = 2 x R 1
10Hz
0.01
Resistor Noise Only
1kHz
2
1
100
1k
10k
100k
100
1k
10k
Noise Bandwidth (Hz)
Source Resistance (Ω)
VOLTAGE NOISE SPECTRAL DENSITY
vs SUPPLY VOLTAGE
VOLTAGE NOISE SPECTRAL DENSITY
vs TEMPERATURE
5
5
3
Voltage Noise (nV/√Hz)
Voltage Noise (nV/√Hz)
10Hz
10Hz
4
1kHz
2
1
4
1kHz
3
2
1
0
±5
±10
±15
–75
±20
–50
–25
0
+25
+50
+75
+100
+125
Ambient Temperature (°C)
Supply Voltage (VCC )
®
5
OPA27, 37
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, ±VCC = ±15VDC, unless otherwise noted.
INPUT VOLTAGE NOISE SPECTRAL DENSITY
10
Current Noise Test Circuit
100kΩ
500kΩ 10kΩ
en
DUT
2
Voltage Noise (nV/√Hz)
o
500kΩ
1
0.8
0.6
0.4
In = √(e n )2 – (130nV)2
o
1M Ω x 100
Warning: This industry-standard equation
is inaccurate and these figures should
be used for comparison purposes only!
0.2
8
6
4
2
0
0.1
100
1k
1
10k
10
OPEN-LOOP FREQUENCY RESPONSE
1k
BIAS AND OFFSET CURRENT vs TEMPERATURE
20
140
Absolute Bias Current (nA)
120
Voltage Gain (dB)
100
Frequency (Hz)
Frequency (Hz)
100
OPA37
80
OPA27
60
40
20
Bias
15
15
Offset
10
10
5
5
20
0
0
10
100
1k
10k
100k
1M
10M
–75
100M
–25
0
+25
+50
+75
0
+125
+100
Frequency (Hz)
Ambient Temperature (°C)
OPA27 CLOSED-LOOP VOLTAGE GAIN AND
PHASE SHIFT vs FREQUENCY (G = 100)
OPA37 CLOSED-LOOP VOLTAGE GAIN AND
PHASE SHIFT vs FREQUENCY (G = 100)
50
50
0
∅
–90
20
Gain
10
–135
0
–180
–10
–225
–20
Voltage Gain (dB)
–45
30
0
40
Phase Shift (degrees)
40
Voltage Gain (dB)
–50
Absolute Offset Current (nA)
10
–45
30
Ø
–90
20
G=5
10
Gain
–135
0
–180
–10
–225
–20
10
100
1k
10k
100k
1M
10M
100M
10
Frequency (Hz)
1k
10k
100k
Frequency (Hz)
®
OPA27, 37
100
6
1M
10M
100M
Phase Shift (degrees)
Current Noise (pA/√Hz)
INPUT CURRENT NOISE SPECTRAL DENSITY
10
8
6
4
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, ±VCC = ±15VDC, unless otherwise noted.
POWER SUPPLY REJECTION vs FREQUENCY
140
120
120
Power Supply Rejection (dB)
Common-Mode Rejection (dB)
COMMON-MODE REJECTION vs FREQUENCY
140
100
80
OPA37
60
OPA27
40
20
0
OPA27
100
–VCC
80
+VCC
60
40
20
0
1
10
100
1k
10k
100k
1M
10M
1
10
100
Frequency (Hz)
1k
10k
100k
1M
10M
Frequency (Hz)
OPEN-LOOP VOLTAGE GAIN vs TEMPERATURE
OPEN-LOOP VOLTAGE GAIN vs SUPPLY VOLTAGE
130
135
Voltage Gain (dB)
125
R L = 600 Ω
120
130
RL = 2kΩ
125
120
115
115
±5
±10
±15
±20
–75
±25
–50
–25
0
+25
+50
+75
+100
Supply Voltage (VCC )
Ambient Temperature (°C)
SUPPLY CURRENT vs SUPPLY VOLTAGE
COMMON-MODE INPUT VOLTAGE RANGE
vs SUPPLY VOLTAGE
6
+15
5
+10
Common-Mode Range (V)
Supply Current (mA)
Voltage Gain (dB)
R L = 2k Ω
+125°C
4
+25°C
3
–55°C
2
1
0
+125
T A = –55°C
T A = +25°C
+5
TA = +125°C
0
TA = –55°C
TA = +25°C
–5
TA = +125°C
–10
–15
0
±5
±10
±15
±20
0
Supply Voltage (VCC )
±5
±10
±15
±20
Supply Voltage (VCC )
®
7
OPA27, 37
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, ±VCC = ±15VDC, unless otherwise noted.
OPA37 SMALL SIGNAL TRANSIENT RESPONSE
+60
+40
+40
Output Voltage (mV)
Output Voltage (mV)
OPA27 SMALL SIGNAL TRANSIENT RESPONSE
+60
+20
0
–20
A VCL = +1
C L = 15pF
–40
+20
0
–20
A V = +5
C L = 25pF
–40
–60
–60
0
0.5
1
1.5
2
0
2.5
0.2
0.4
OPA27 LARGE SIGNAL TRANSIENT RESPONSE
0.8
1.0
1.2
OPA37 LARGE SIGNAL TRANSIENT RESPONSE
+6
+15
+4
+10
Output Voltage (V)
Output Voltage (V)
0.6
Time (µs)
Time (µs)
+2
0
–2
A VCL = +1
–4
+5
0
–5
A V = +5
–10
–6
–15
0
2
4
6
8
10
0
12
Time (µs)
1
2
3
4
5
6
Time (µs)
APPLICATIONS INFORMATION
OFFSET VOLTAGE ADJUSTMENT
THERMOELECTRIC POTENTIALS
The OPA27/37 is laser-trimmed to microvolt-level input
offset voltage and for very low input offset voltage drift.
The OPA27/37 offset voltage is laser-trimmed and will require no further trim for most applications. Offset voltage
drift will not be degraded when the input offset is nulled with
a 10kΩ trim potentiometer. Other potentiometer values from
1kΩ to 1MΩ can be used but VOS drift will be degraded by
an additional 0.1 to 0.2µV/°C. Nulling large system offsets
by use of the offset trim adjust will degrade drift performance
by approximately 3.3µV/°C per millivolt of offset. Large
system offsets can be nulled without drift degradation by
input summing.
Careful layout and circuit design techniques are necessary to
prevent offset and drift errors from external thermoelectric
potentials. Dissimilar metal junctions can generate small
EMFs if care is not taken to eliminate either their sources
(lead-to-PC, wiring, etc.) or their temperature difference. See
Figure 11.
Short, direct mounting of the OPA27/37 with close spacing
of the input pins is highly recommended. Poor layout can
result in circuit drifts and offsets which are an order of
magnitude greater than the operational amplifier alone.
The conventional offset voltage trim circuit is shown in
Figure 3. For trimming very small offsets, the higher resolution circuit shown in Figure 4 is recommended.
The OPA27/37 can replace 741-type operational amplifiers
by removing or modifying the trim circuit.
®
OPA27, 37
8
COMPENSATION
Although internally compensated for unity-gain stability, the
OPA27 may require a small capacitor in parallel with a
feedback resistor (RF) which is greater than 2kΩ. This
capacitor will compensate the pole generated by RF and CIN
and eliminate peaking or oscillation.
NOISE: BIPOLAR VERSUS FET
Low-noise circuit design requires careful analysis of all noise
sources. External noise sources can dominate in many cases,
so consider the effect of source resistance on overall operational amplifier noise performance. At low source impedances, the lower voltage noise of a bipolar operational
amplifier is superior, but at higher impedances the high
current noise of a bipolar amplifier becomes a serious liability. Above about 15kΩ the Burr-Brown OPA111 low-noise
FET operational amplifier is recommended for lower total
noise than the OPA27 (see Figure 5).
INPUT PROTECTION
Back-to-back diodes are used for input protection on the
OPA27/37. Exceeding a few hundred millivolts differential
input signal will cause current to flow and without external
current limiting resistors the input will be destroyed.
+VCC
(1)
Accidental static discharge as well as high current can
damage the amplifier’s input circuit. Although the unit may
still be functional, important parameters such as input offset
voltage, drift, and noise may be permanently damaged as will
any precision operational amplifier subjected to this abuse.
NOTE: (1) 10kΩ to 1MΩ
Trim Potentiometer
(10kΩ Recommended).
7
8
2
1
Transient conditions can cause feedthrough due to the
amplifier’s finite slew rate. When using the OP-27 as a unitygain buffer (follower) a feedback resistor of 1kΩ is recommended (see Figure 6).
6
OPA27/37
3
4
±4mV Typical Trim Range
–VCC
RF
≈ 1kΩ
FIGURE 3. Offset Voltage Trim.
+VCC
–
(1)
NOTE: (1) 1kΩ Trim Potentiometer.
4.7kΩ
7
Input
OPA27
+
Output
1.9V/µs
4.7kΩ
8
2
1
OPA27/37
FIGURE 6. Pulsed Operation.
6
3
4
G ≈ 40dB at 1kHz.
Metal film resistors.
Film capacitors.
RL and CL per cartridge
manufacturer’s
recommendations.
100Ω
±280µV Typical Trim Range
–VCC
FIGURE 4. High Resolution Offset Voltage Trim.
Voltage Noise Spectral Density, EO
Typical at 1kHz (nV/√Hz)
1k
0.01µF
2
3
OPA111 + Resistor
Moving
Magnet
Cartridge
RS
OPA111 + Resistor
OPA37
6
1µF
Output
20kΩ
RL
CL
Resistor Noise Only
FIGURE 7. Low-Noise RIAA Preamplifier.
10
Resistor Noise Only
1
100
0.03µF
97.6kΩ
OPA27 + Resistor
EO
100
7.87kΩ
1kΩ
OPA27 + Resistor
1k
10k
100k
1M
1kΩ
10M
Input
2
Source Resistance, RS (Ω)
3
EO = √en2 + (inRS)2 + 4kTRS
OPA27
6
Output
FO = 1kHz
FIGURE 8. Unity-Gain Inverting Amplifier.
FIGURE 5. Voltage Noise Spectral Density Versus Source
Resistance.
®
9
OPA27, 37
G ≈ 50dB at 1kHz.
Metal film resistors.
Film capacitors.
RL and CL per head
manufacturer’s
recommendations.
1kΩ
1kΩ
2
Input
250Ω
3
100Ω
6
OPA37
4.99kΩ
316kΩ
2
Output
3
500pF
RL
0.01µF
OPA37
6
1µF
20kΩ
CL
Magnetic Tape Head
FIGURE 10. NAB Tape Head Preamplifier.
FIGURE 9. High Slew Rate Unity-Gain Inverting Amplifier.
Total Gain = 10 6
10kΩ
10Ω
G =1k
DUT
Offset
10Hz LowPass Filter
Chart
Recorder
10mV/mm
5mm/s
A. 741 noise with circuit well-shielded from air
currents and RFI. (Note scale change.)
5µV
B. OP-07AH with circuit well-shielded from air
currents and RFI.
0.5µV
C. OPA27AJ with circuit well-shielded from air
currents and RFI. (Represents ultimate
OPA27 performance potential.)
0.5µV
D. OPA27 with circuit unshielded and exposed
to normal lab bench-top air currents.
(External thermoelectric potentials far
exceed OPA27 noise.)
0.5µV
E. OPA27 with heat sink and shield which
protects input leads from air currents.
Conditions same as (D).
0.5µV
FIGURE 11. Low Frequency Noise Comparison.
®
OPA27, 37
10
Output
3
–In
Gain = 100
6
OPA37
2
For gain = 1000 use INA106 differential amplifier.
Bandwidth ≈ 500kHz
Burr-Brown INA105
Differential Amplifier
RF
5kΩ
RG
101Ω
2
25kΩ
5
Input Stage Gain = 1 + 2RF /RG
RF
5kΩ
3
2
25kΩ
6
Output
25kΩ
6
OPA37
3
+In
25kΩ
1
FIGURE 12. Low Noise Instrumentation Amplifier.
1kΩ
0.1µF
200Ω
2
500pF
3
0.1µF
6
OPA37
100Ω
Output
100kΩ
2
2kΩ
1MΩ
3
EDO 6166
Transducer
Frequency Response
≈ 1kHz to 50kHz
Dexter 1M
Thermopile
Detector
FIGURE 13. Hydrophone Preamplifier.
OPA27
6
Output
NOTE: Use metal film resistors
and plastic film capacitor. Circuit
must be well shielded to achieve
low noise.
Responsivity ≈ 2.5 x 104V/W
Output Noise ≈ 30µVrms, 0.1Hz to 10Hz
20pF
FIGURE 14. Long-Wavelength Infrared Detector Amplifier.
TTL INPUT
GAIN
“1”
“0”
+1
–1
9.76kΩ
500Ω
10kΩ
Input
D1
D2
2
4.99kΩ
S1
S2
3
6
OPA27
Output
8
1
4.75kΩ
TTL
In
Balance
Trim
4.75kΩ
1kΩ
DG188
Offset
Trim
+VCC
FIGURE 15. High Performance Synchronous Demodulator.
®
11
OPA27, 37
Gain = –1010V/V
Full Power Bandwidth ≈ 180kHz
Gain Bandwidth ≈ 500MHz
Equivalent Noise Resistance ≈ 50Ω
Input
20Ω
2kΩ
Signal-to-Noise Ratio ∝ √N
since amplifier noise is
uncorrelated.
2
3
20Ω
6
2kΩ
6
2kΩ
OPA37
2kΩ
2
3
20Ω
OPA37
2kΩ
2kΩ
2
2
2kΩ
6
3
20Ω
OPA37
2
20Ω
6
2kΩ
6
2kΩ
OPA37
2kΩ
2
3
OPA37
N = 10 Each OPA37EZ
FIGURE 16. Ultra-Low Noise “N” Stage Parallel Amplifier.
®
OPA27, 37
OPA37
Output
2kΩ
3
6
3
12
5V
5V
+10V
Output
Output
+10V
0V
0V
–10V
–10V
5µs
RS = 50Ω
5µs
1kΩ
RS = 50Ω
1kΩ
2
2
Input
3
6
OPA27
3
250Ω
Output
OPA37
6
Output
500pF
Input
FIGURE 18. High Slew Rate Unity-Gain Buffer.
FIGURE 17. Unity-Gain Buffer.
+15V
200Ω
10µF/20V
20kΩ
100Ω
10kΩ
+
VIRTEC V1000
50Ω
Planar Tunnel
Input 0.01µF
Diode
RFC
1
2
3
200Ω
OPA37
6
2
Video
Output
100µF/20V
Tantalum
2
3
OPA27
+
10kΩ
500pF
Siemens LHI 948
FIGURE 19. RF Detector and Video Amplifier.
6
Output
10kΩ
3
FIGURE 20. Balanced Pyroelectric Infrared Detector.
4.8V
+
1kΩ
Airpax
Magnetic
Pickup
2
3
OPA27
6
0
Output
–
fOUT ∝ RPM X N
Where N = Number of Gear Teeth
FIGURE 21. Magnetic Tachometer.
®
13
OPA27, 37
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