©1990 Burr-Brown Corporation PDS-1081E Printed in U.S.A. August, 1997
OPA177
FEATURES
●LOW OFFSET VOLTAGE: 25µV max
●LOW DRIFT: 0.3µV/°C
●HIGH OPEN-LOOP GAIN: 130dB min
●LOW QUIESCENT CURRENT: 1.5mA typ
●REPLACES INDUSTRY-STANDARD OP
AMPS: OP-07, OP-77, OP-177, AD707,
ETC.
APPLICATIONS
●PRECISION INSTRUMENTATION
●DATA ACQUISITION
●TEST EQUIPMENT
●BRIDGE AMPLIFIER
●THERMOCOUPLE AMPLIFIER
Precision
OPERATIONAL AMPLIFIER
14kΩ
500Ω
Trim
8
V+
7
Trim
1
+In
3
–In
2
V–
4
25Ω
30Ω
V
6
O
20µA
500Ω
DESCRIPTION
The OPA177 precision bipolar op amp feature very
low offset voltage and drift. Laser-trimmed offset,
drift and input bias current virtually eliminate the need
for costly external trimming. The high performance
and low cost make them ideally suited to a wide range
of precision instrumentation.
The low quiescent current of the OPA177 dramati-
cally reduce warm-up drift and errors due to thermo-
electric effects in input interconnections. It provides
an effective alternative to chopper-stabilized amplifi-
ers. The low noise of the OPA177 maintains accuracy.
OPA177 performance gradeouts are available. Pack-
aging options include 8-pin plastic DIP
and SO-8 surface-mount packages.
®
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OPA177
OPA177
2
®
OPA177
OPA177 SPECIFICATIONS
At VS = ±15V, TA = +25°C, unless otherwise noted.
OPA177F OPA177G
PARAMETER CONDITION MIN TYP MAX MIN TYP MAX UNITS
OFFSET VOLTAGE
Input Offset Voltage 10 25 20 60 µV
Long-Term Input Offset(1) 0.3 0.4 µV/Mo
Voltage Stability
Offset Adjustment Range RP = 20kΩ±3✻mV
Power Supply Rejection Ratio VS = ±3V to ±18V 115 125 110 120 dB
INPUT BIAS CURRENT
Input Offset Current 0.3 1.5 ✻2.8 nA
Input Bias Current 0.5 ±2✻±2.8 nA
NOISE
Input Noise Voltage 1Hz to 100Hz(2) 85 150 ✻✻nVrms
Input Noise Current 1Hz to 100Hz 4.5 ✻pArms
INPUT IMPEDANCE
Input Resistance Differential Mode(3) 26 45 18.5 ✻MΩ
Common-Mode 200 ✻GΩ
INPUT VOLTAGE RANGE
Common-Mode Input Range(4) ±13 ±14 ✻✻ V
Common-Mode Rejection VCM = ±13V 130 140 115 ✻dB
OPEN-LOOP GAIN RL ≥ 2kΩ
Large Signal Voltage Gain VO = ±10V(5) 5110 12,000 2000 6000 V/mV
OUTPUT
Output Voltage Swing RL ≥ 10kΩ±13.5 ±14 ✻✻ V
R
L ≥ 2kΩ±12.5 ±13 ✻✻ V
R
L ≥ 1kΩ±12 ±12.5 ✻✻ V
Open-Loop Output Resistance 60 ✻Ω
FREQUENCY RESPONSE
Slew Rate RL ≥ 2kΩ0.1 0.3 ✻✻ V/µs
Closed-Loop Bandwidth G = +1 0.4 0.6 ✻✻ MHz
POWER SUPPLY
Power Consumption VS = ±15V, No Load 40 60 ✻✻ mW
VS = ±3V, No Load 3.5 4.5 ✻✻ mW
Supply Current VS = ±15V, No Load 1.3 2 ✻✻ mA
At VS = ±15V, –40°C ≤ TA ≤ +85°C, unless otherwise noted.
OFFSET VOLTAGE
Input Offset Voltage 15 40 20 100 µV
Average Input Offset 0.1 0.3 0.7 1.2 µV/°C
Voltage Drift
Power Supply Rejection Ratio VS = ±3V to ±18V 110 120 106 115 dB
INPUT BIAS CURRENT
Input Offset Current 0.5 2.2 ✻4.5 nA
Average Input Offset Current 1.5 40 ✻85 pA/°C
Drift(6)
Input Bias Current 0.5 ±4✻±6nA
Average Input Bias Current 8 40 15 60 pA/°C
Drift(6)
INPUT VOLTAGE RANGE
Common-Mode Input Range ±13 ±13.5 ✻✻ V
Common-Mode Rejection VCM = ±13V 120 140 110 ✻dB
OPEN-LOOP GAIN
Large Signal Voltage Gain RL≥2kΩ, VO=±10V 2000 6000 1000 4000 V/mV
OUTPUT
Output Voltage Swing RL ≥ 2kΩ±12 ±13 ✻✻ V
POWER SUPPLY
Power Consumption VS=±15V, No Load 60 75 ✻✻ mW
Supply Current VS=±15V, No Load 2 25 ✻✻ mA
✻ Same as specification for product to left.
NOTES: (1) Long-Term Input Offset Voltage Stability refers to the averaged trend line of VOS vs time over extended periods after the first 30 days of operation. Excluding
the initial hour of operation, changes in VOS during the first 30 operating days are typically less than 2µV. (2) Sample tested. (3) Guaranteed by design. (4) Guaranteed
by CMRR test condition. (5) To insure high open-loop gain throughout the ±10V output range, AOL is tested at –10V ≤ VO ≤ 0V, 0V ≤ VO ≤ +10V, and –10V ≤ VO ≤ +10V.
(6) Guaranteed by end-point limits.
3
®
OPA177
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.
PIN CONFIGURATION
Top View DIP/SOIC
ABSOLUTE MAXIMUM RATINGS
ELECTROSTATIC
DISCHARGE SENSITIVITY
Any integrated circuit can be damaged by ESD. Burr-Brown
recommends that all integrated circuits be handled with
appropriate precautions. ESD can cause damage ranging
from subtle performance degradation to complete device
failure. Precision integrated circuits may be more suscep-
tible to damage because very small parametric changes
could cause the device not to meet published specifications.
Burr-Brown’s standard ESD test method consists of five
1000V positive and negative discharges (100pF in series
with 1.5kΩ) applied to each pin.
Failure to observe proper handling procedures could result
in small changes to the OPA177’s input bias current.
1
2
3
4
8
7
6
5
Offset Trim
–In
+In
V–
Offset Trim
V+
V
No Internal Connection
O
Power Supply Voltage ....................................................................... ±22V
Differential Input Voltage ................................................................... ±30V
Input Voltage ....................................................................................... ±VS
Output Short Circuit ................................................................. Continuous
Operating Temperature:
Plastic DIP (P), SO-8 (S).............................................. –40°C to +85°C
θ
JA (PDIP) ................................................................................. 100°C/W
θ
JA (SOIC)................................................................................. 160°C/W
Storage Temperature:
Plastic DIP (P), SO-8 (S)............................................ –65°C to +125°C
Junction Temperature.................................................................... +150°C
Lead Temperature (soldering, 10s) P packages ........................... +300°C
(soldering, 3s) S package............................... +260°C
PACKAGE
DRAWING TEMPERATURE
PRODUCT PACKAGE NUMBER(1) RANGE
OPA177FP 8-Pin Plastic DIP 006 –40°C to +85°C
OPA177GP 8-Pin Plastic DIP 006 –40°C to +85°C
OPA177GS SO-8 Surface-Mount 182 –40°C to +85°C
NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix C of Burr-Brown IC Data Book.
PACKAGE/ORDERING INFORMATION
4
®
OPA177
TYPICAL PERFORMANCE CURVES
At TA = +25°C, VS = ±15V, unless otherwise noted.
10 30 50 700204060
30
25
20
15
10
5
0
Absolute Change in Input
Offset Voltage (µV)
Time (s)
OFFSET VOLTAGE CHANGE
DUE TO THERMAL SHOCK
80
Device Immersed in 70°C Inert Liquid
Plastic DIP
CLOSED-LOOP RESPONSE vs FREQUENCY
100
80
60
40
20
0
–20 10 100 1k 10k 100k 1M 10M
Closed-Loop Gain (dB)
Frequency (Hz)
3
2
1
0
–1
–2
–3
Offset Voltage Change (µV)
0 30 60 90 120
Time from Power Supply Turn-On (s)
WARM-UP OFFSET VOLTAGE DRIFT
15 45 75 105
17.5
15
12.5
10
7.5
5
2.5
0
V
OUT
(V)
0 6 12 18 24 30 36
I
OUT
(mA)
MAXIMUM V
OUT
vs I
OUT
(Positive Swing)
V
S
= ±18V
V
S
= ±15V
V
S
= ±12V
V
S
= ±15V
–17.5
–15
–12.5
–10
–7.5
–5
–2.5
0
V
OUT
(V)
0 –2 –4 –6 –8 –10 –12
–I
OUT
(mA)
MAXIMUM V
OUT
vs I
OUT
(Negative Swing)
V
S
= ±18V
V
S
= ±15V
V
S
= ±12V
V
S
= ±15V
1
0.1
0.01
0.001
THD + N (%)
1k 10k 100k
Frequency (Hz)
TOTAL HARMONIC DISTORTION AND NOISE
vs FREQUENCY
A = 20dB, 3Vrms, 10kΩ load
30kHz low pass filtered
Inverting
Noninverting
5
®
OPA177
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, VS = ±15V, unless otherwise noted.
150
140
130
120
110
100
90
80
CMRR (dB)
1 10 100 1k 10k 100k
Frequency (Hz)
CMRR vs FREQUENCY
OPEN-LOOP GAIN/PHASE vs FREQUENCY
160
140
120
100
80
60
40
20
0
Open-Loop Gain (dB)
0.01 1 10 100 1k 10k 100k 1M0.1
Frequency (Hz)
0
45
90
135
180
Phase Shift (Degrees)
Phase
Gain
2
1
0
–1
–2–40 –15 10 35 60 85
Temperature (°C)
INPUT BIAS AND INPUT OFFSET CURRENT
vs TEMPERATURE
Input Bias and Input Offset Current (nA)
I
B
I
OS
150
130
110
90
70
50
Power Supply Rejection (dB)
1 10 100 1k 10k0.1 Frequency (Hz)
POWER SUPPLY REJECTION
vs FREQUENCY
1k
100
10
1
Input Noise Voltage (nV/√Hz)
1
Frequency (Hz)
INPUT NOISE VOLTAGE DENSITY vs FREQUENCY
10 100 1k 10k
R = 0
S
R = R = 200k
Thermal noise of
source resistors
included.
S1 S2 Ω
10
1
0.1
0.01
RMS Noise (µV)
100 1k 10k 100k
Bandwidth (Hz)
TOTAL NOISE vs BANDWIDTH
(0.1Hz to Frequency Indicated)
6
®
OPA177
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, VS = ±15V, unless otherwise noted.
40
35
30
25
20
15
Output Short-Circuit Current (mA)
01234
Time from Output Being Shorted (min)
OUTPUT SHORT-CIRCUIT CURRENT vs TIME
SC
I –
SC
I +
20
15
10
5
0
Maximum Output (V)
100 10k
Load Resistance to Ground ( )
MAXIMUM OUTPUT VOLTAGE vs LOAD RESISTANCE
1k
Ω
Negative
Output
Positive
Output
32
28
24
20
16
12
8
4
0
Peak-to-Peak Amplitude (V)
1k 10k 100k 1M
Frequency (Hz)
MAXIMUM OUTPUT SWING vs FREQUENCY
G = +1
R = 2k
L
Ω
100
10
1
Power Consumption (mW)
0 10203040
Total Supply Voltage (V)
POWER CONSUMPTION vs POWER SUPPLY
7
®
OPA177
APPLICATIONS INFORMATION
The OPA177 is unity-gain stable, making it easy to use and
free from oscillations in the widest range of circuitry. Ap-
plications with noisy or high impedance power supply lines
may require decoupling capacitors close to the device pins.
In most cases 0.1µF ceramic capacitors are adequate.
The OPA177 has very low offset voltage and drift. To
achieve highest performance, circuit layout and mechanical
conditions must be optimized. Offset voltage and drift can
be degraded by small thermoelectric potentials at the op amp
inputs. Connections of dissimilar metals will generate ther-
mal potential which can mask the ultimate performance of
the OPA177. These thermal potentials can be made to cancel
by assuring that they are equal in both input terminals.
1. Keep connections made to the two input terminals close
together.
2. Locate heat sources as far as possible from the critical
input circuitry.
3. Shield the op amp and input circuitry from air currents
such as cooling fans.
OFFSET VOLTAGE ADJUSTMENT
The OPA177 has been laser-trimmed for low offset voltage
and drift so most circuits will not require external adjust-
ment. Figure 1 shows the optional connection of an external
potentiometer to adjust offset voltage. This adjustment should
not be used to compensate for offsets created elsewhere in a
system since this can introduce excessive temperature drift.
INPUT PROTECTION
The inputs of the OPA177 are protected with 500Ω series
input resistors and diode clamps as shown in the simplified
circuit diagram. The inputs can withstand ±30V differential
inputs without damage. The protection diodes will, of course,
conduct current when the inputs are overdriven. This may
disturb the slewing behavior of unity-gain follower applica-
tions, but will not damage the op amp.
NOISE PERFORMANCE
The noise performance of the OPA177 is optimized for
circuit impedances in the range of 2kΩ to 50kΩ. Total noise
in an application is a combination of the op amp’s input
voltage noise and input bias current noise reacting with
circuit impedances. For applications with higher source
impedance, the OPA627 FET-input op amp will generally
provide lower noise. For very low impedance applications,
the OPA27 will provide lower noise.
INPUT BIAS CURRENT CANCELLATION
The input stage base current of the OPA177 is internally
compensated with an equal and opposite cancellation cur-
rent. The resulting input bias current is the difference
between the input stage base current and the cancellation
current. This residual input bias current can be positive or
negative.
When the bias current is cancelled in this manner, the input
bias current and input offset current are approximately the
same magnitude. As a result, it is not necessary to balance
the DC resistance seen at the two input terminals (Figure 2).
A resistor added to balance the input resistances may actu-
ally increase offset and noise.
FIGURE 1. Optional Offset Nulling Circuit.
OPA177 V
2
3
18
Trim Range is approximately ±3.0mV
V+
20kΩ
OUT
V
IN
Op Amp
(a)
R
B
OPA177
(b)
No bias current
cancellation resistor needed
Conventional op amp with
external bias current
cancellation resistor.
OPA177 with no external
bias current cancellation
resistor.
= R
2
|| R
1
R
2
R
1
R
2
R
1
FIGURE 2. Input Bias Current Cancellation.
