OP2177ARMZ-R7 [ADI]

Precision Low Noise, Low Input Bias Current Dual Operational Amplifier;
OP2177ARMZ-R7
型号: OP2177ARMZ-R7
厂家: ADI    ADI
描述:

Precision Low Noise, Low Input Bias Current Dual Operational Amplifier

放大器 PC 光电二极管
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Precision Low Noise, Low Input  
Bias Current Operational Amplifiers  
OP1177/OP2177/OP4177  
FEATURES  
PIN CONFIGURATIONS  
Low offset voltage: 60 μV maximum  
Very low offset voltage drift: 0.7 μV/°C maximum  
Low input bias current: 2 nA maximum  
Low noise: 8 nV/√Hz typical  
CMRR, PSRR, and AVO > 120 dB minimum  
Low supply current: 400 μA per amplifier  
Dual supply operation: 2.ꢀ V to 1ꢀ V  
Unity-gain stable  
NC  
–IN  
+IN  
V–  
NC  
V+  
1
2
3
4
8
7
6
5
OP1177  
1
8
NC  
–IN  
+IN  
V–  
NC  
V+  
OUT  
NC  
OUT  
NC  
OP1177  
4
5
NC = NO CONNECT  
NC = NO CONNECT  
Figure 1. 8-Lead MSOP (RM Suffix)  
Figure 2. 8-Lead SOIC_N (R Suffix)  
OUT A  
–IN A  
+IN A  
V–  
V+  
1
2
3
4
8
7
6
5
No phase reversal  
Inputs internally protected beyond supply voltage  
OUT B  
–IN B  
+IN B  
OP2177  
1
8
OUT A  
–IN A  
+IN A  
V–  
V+  
OUT B  
–IN B  
+IN B  
OP2177  
4
5
APPLICATIONS  
Figure 3. 8-Lead MSOP (RM Suffix)  
Figure 4. 8-Lead SOIC_N (R Suffix)  
Wireless base station control circuits  
Optical network control circuits  
Instrumentation  
Sensors and controls  
Thermocouples  
Resistor thermal detectors (RTDs)  
Strain bridges  
Shunt current measurements  
Precision filters  
OUT A  
1
2
OUT D  
–IN D  
14  
13  
–IN A  
+IN A  
V+  
+IN D  
V–  
3
4
12  
11  
OP4177  
OUT A  
OUT D  
–IN D  
+IN D  
V–  
1
7
14  
–IN A  
+IN A  
V+  
+IN B  
–IN B  
+IN C  
–IN C  
OUT C  
+IN B  
–IN B  
5
6
7
10  
9
OP4177  
+IN C  
–IN C  
OUT C  
8
OUT B  
8
OUT B  
Figure 5. 14-Lead SOIC_N (R Suffix)  
Figure 6. 14-Lead TSSOP (RU Suffix)  
GENERAL DESCRIPTION  
performance in the SOIC package. MSOP and TSSOP are  
available in tape and reel only.  
The OPx177 family consists of very high precision, single, dual,  
and quad amplifiers featuring extremely low offset voltage and  
drift, low input bias current, low noise, and low power consump-  
tion. Outputs are stable with capacitive loads of over 1000 pF  
with no external compensation. Supply current is less than 500 μA  
per amplifier at 30 V. Internal 500 Ω series resistors protect the  
inputs, allowing input signal levels several volts beyond either  
supply without phase reversal.  
The OPx177 family offers the widest specified temperature  
range of any high precision amplifier in surface-mount packaging.  
All versions are fully specified for operation from −40°C to  
+125°C for the most demanding operating environments.  
Applications for these amplifiers include precision diode  
power measurement, voltage and current level setting, and  
level detection in optical and wireless transmission systems.  
Additional applications include line-powered and portable  
instrumentation and controls—thermocouple, RTD, strain-  
bridge, and other sensor signal conditioning—and precision filters.  
Unlike previous high voltage amplifiers with very low offset  
voltages, the OP1177 (single) and OP2177 (dual) amplifiers  
are available in tiny 8-lead surface-mount MSOP and 8-lead  
narrow SOIC packages. The OP4177 (quad) is available in  
TSSOP and 14-lead narrow SOIC packages. Moreover, specified  
performance in the MSOP and the TSSOP is identical to  
Rev. G  
Information furnished by Analog Devices is believed to be accurate and reliable. However, no  
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other  
rights of third parties that may result from its use. Specifications subject to change without notice. No  
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.  
Trademarks and registeredtrademarks arethe property of their respective owners.  
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.  
Tel: 781.329.4700  
www.analog.com  
Fax: 781.461.3113 ©2001–2009 Analog Devices, Inc. All rights reserved.  
 
 
OP1177/OP2177/OP4177  
TABLE OF CONTENTS  
Features .............................................................................................. 1  
Overload Recovery Time .......................................................... 15  
THD + Noise............................................................................... 16  
Capacitive Load Drive ............................................................... 16  
Stray Input Capacitance Compensation.................................. 17  
Reducing Electromagnetic Interference.................................. 17  
Proper Board Layout.................................................................. 18  
Difference Amplifiers ................................................................ 18  
A High Accuracy Thermocouple Amplifier........................... 19  
Low Power Linearized RTD...................................................... 19  
Single Operational Amplifier Bridge....................................... 20  
Realization of Active Filters .......................................................... 21  
Band-Pass KRC or Sallen-Key Filter........................................ 21  
Channel Separation.................................................................... 21  
References on Noise Dynamics and Flicker Noise ............... 21  
Outline Dimensions....................................................................... 22  
Ordering Guide .......................................................................... 24  
Applications....................................................................................... 1  
Pin Configurations ........................................................................... 1  
General Description......................................................................... 1  
Revision History ............................................................................... 2  
Specifications..................................................................................... 3  
Electrical Characteristics............................................................. 4  
Absolute Maximum Ratings............................................................ 5  
Thermal Resistance ...................................................................... 5  
ESD Caution.................................................................................. 5  
Typical Performance Characteristics ............................................. 6  
Functional Description.................................................................. 14  
Total Noise-Including Source Resistors................................... 14  
Gain Linearity ............................................................................. 14  
Input Overvoltage Protection ................................................... 15  
Output Phase Reversal............................................................... 15  
Settling Time............................................................................... 15  
REVISION HISTORY  
Changes to Figure 67 and Figure 68............................................. 21  
Removed SPICE Model Section ................................................... 21  
Updated Outline Dimensions....................................................... 22  
Changes to Ordering Guide.......................................................... 24  
11/09—Rev. F to Rev. G  
Changes to Figure 64...................................................................... 19  
Changes to Ordering Guide .......................................................... 24  
Updated Outline Dimensions....................................................... 22  
4/04—Rev. B to Rev. C  
5/09—Rev. E to Rev. F  
Changes to Ordering Guide.............................................................4  
Changes to TPC 6..............................................................................5  
Changes to TPC 26............................................................................7  
Updated Outline Dimensions....................................................... 17  
Changes to Figure 64...................................................................... 19  
Changes to Ordering Guide .......................................................... 24  
10/07—Rev. D to Rev. E  
Changes to General Description .................................................... 1  
Changes to Table 4............................................................................ 5  
Updated Outline Dimensions....................................................... 22  
4/02—Rev. A to Rev. B  
Added OP4177.........................................................................Global  
Edits to Specifications.......................................................................2  
Edits to Electrical Characteristics Headings..................................4  
Edits to Ordering Guide ...................................................................4  
7/06—Rev. C to Rev. D  
Changes to Table 4............................................................................ 5  
Changes to Figure 51...................................................................... 14  
Changes to Figure 52...................................................................... 15  
Changes to Figure 54...................................................................... 16  
Changes to Figure 58 to Figure 61................................................ 17  
Changes to Figure 62 and Figure 63............................................. 18  
Changes to Figure 64...................................................................... 19  
Changes to Figure 65 and Figure 66............................................. 20  
11/01—Rev. 0 to Rev. A  
Edit to Features ..................................................................................1  
Edits to TPC 6 ...................................................................................5  
7/01—Revision 0: Initial Version  
Rev. G | Page 2 of 24  
 
OP1177/OP2177/OP4177  
SPECIFICATIONS  
ELECTRICAL CHARACTERISTICS  
VS = 5.0 V, VCM = 0 V, TA = 25°C, unless otherwise noted.  
Table 1.  
Parameter  
Symbol  
Conditions  
Min  
Typ1  
Max  
Unit  
INPUT CHARACTERISTICS  
Offset Voltage  
OP1177  
VOS  
VOS  
VOS  
VOS  
IB  
15  
15  
25  
25  
+0.5  
+0.2  
60  
75  
100  
120  
+2  
μV  
μV  
μV  
μV  
nA  
nA  
V
dB  
dB  
V/mV  
OP2177/OP4177  
OP1177/OP2177  
OP4177  
Input Bias Current  
Input Offset Current  
Input Voltage Range  
Common-Mode Rejection Ratio  
−40°C < TA < +125°C  
−40°C < TA < +125°C  
−40°C < TA < +125°C  
−40°C < TA < +125°C  
−2  
−1  
−3.5  
120  
118  
1000  
IOS  
+1  
+3.5  
CMRR  
AVO  
VCM = −3.5 V to +3.5 V  
−40°C < TA < +125°C  
RL = 2 kΩ, VO = −3.5 V to +3.5 V  
126  
125  
2000  
Large Signal Voltage Gain  
Offset Voltage Drift  
OP1177/OP2177  
ΔVOS/ΔT  
ΔVOS/ΔT  
−40°C < TA < +125°C  
−40°C < TA < +125°C  
0.2  
0.3  
0.7  
0.9  
μV/°C  
μV/°C  
OP4177  
OUTPUT CHARACTERISTICS  
Output Voltage High  
Output Voltage Low  
Output Current  
VOH  
VOL  
IOUT  
IL = 1 mA, −40°C < TA < +125°C  
IL = 1 mA, −40°C < TA < +125°C  
VDROPOUT < 1.2 V  
+4  
+4.1  
−4.1  
10  
V
V
mA  
−4  
POWER SUPPLY  
Power Supply Rejection Ratio  
OP1177  
PSRR  
PSRR  
ISY  
VS = 2.5 V to 15 V  
−40°C < TA < +125°C  
VS = 2.5 V to 15 V  
−40°C < TA < +125°C  
VO = 0 V  
120  
115  
118  
114  
130  
125  
121  
120  
400  
500  
dB  
dB  
dB  
dB  
μA  
μA  
OP2177/OP4177  
Supply Current per Amplifier  
500  
600  
−40°C < TA < +125°C  
DYNAMIC PERFORMANCE  
Slew Rate  
Gain Bandwidth Product  
NOISE PERFORMANCE  
Voltage Noise  
Voltage Noise Density  
Current Noise Density  
MULTIPLE AMPLIFIERS CHANNEL SEPARATION  
SR  
GBP  
RL = 2 kΩ  
0.7  
1.3  
V/μs  
MHz  
en p-p  
en  
in  
0.1 Hz to 10 Hz  
f = 1 kHz  
f = 1 kHz  
DC  
0.4  
7.9  
0.2  
μV p-p  
nV/√Hz  
pA/√Hz  
μV/V  
8.5  
CS  
0.01  
−120  
f = 100 kHz  
dB  
1 Typical values cover all parts within one standard deviation of the average value. Average values given in many competitor data sheets as typical give unrealistically  
low estimates for parameters that can have both positive and negative values.  
Rev. G | Page 3 of 24  
 
OP1177/OP2177/OP4177  
ELECTRICAL CHARACTERISTICS  
VS = 15 V, VCM = 0 V, TA = 25°C, unless otherwise noted.  
Table 2.  
Parameter  
Symbol  
Conditions  
Min  
Typ1  
Max  
Unit  
INPUT CHARACTERISTICS  
Offset Voltage  
OP1177  
VOS  
VOS  
VOS  
VOS  
IB  
15  
15  
25  
25  
+0.5  
+0.2  
60  
75  
100  
120  
+2  
μV  
μV  
μV  
μV  
nA  
nA  
V
OP2177/OP4177  
OP1177/OP2177  
OP4177  
Input Bias Current  
Input Offset Current  
Input Voltage Range  
Common-Mode Rejection Ratio  
−40°C < TA < +125°C  
−40°C < TA < +125°C  
−40°C < TA < +125°C  
−40°C < TA < +125°C  
−2  
−1  
−13.5  
IOS  
+1  
+13.5  
CMRR  
AVO  
VCM = −13.5 V to +13.5 V,  
−40°C < TA < +125°C  
RL = 2 kΩ, VO = –13.5 V to +13.5 V  
120  
1000  
125  
3000  
dB  
V/mV  
Large Signal Voltage Gain  
Offset Voltage Drift  
OP1177/OP2177  
ΔVOS/ΔT  
ΔVOS/ΔT  
−40°C < TA < +125°C  
−40°C < TA < +125°C  
0.2  
0.3  
0.7  
0.9  
μV/°C  
μV/°C  
OP4177  
OUTPUT CHARACTERISTICS  
Output Voltage High  
Output Voltage Low  
Output Current  
Short-Circuit Current  
POWER SUPPLY  
VOH  
VOL  
IOUT  
ISC  
IL = 1 mA, −40°C < TA < +125°C  
IL = 1 mA, −40°C < TA < +125°C  
VDROPOUT < 1.2 V  
+14  
+14.1  
−14.1  
10  
V
V
mA  
mA  
−14  
25  
Power Supply Rejection Ratio  
OP1177  
PSRR  
PSRR  
ISY  
VS = 2.5 V to 15 V  
−40°C < TA < +125°C  
VS = 2.5 V to 15 V  
−40°C < TA < +125°C  
VO = 0 V  
120  
115  
118  
114  
130  
125  
121  
120  
400  
500  
dB  
dB  
dB  
dB  
μA  
μA  
OP2177/OP4177  
Supply Current per Amplifier  
500  
600  
−40°C < TA < +125°C  
DYNAMIC PERFORMANCE  
Slew Rate  
Gain Bandwidth Product  
NOISE PERFORMANCE  
Voltage Noise  
Voltage Noise Density  
Current Noise Density  
MULTIPLE AMPLIFIERS CHANNEL SEPARATION  
SR  
GBP  
RL = 2 kΩ  
0.7  
1.3  
V/μs  
MHz  
en p-p  
en  
in  
0.1 Hz to 10 Hz  
f = 1 kHz  
f = 1 kHz  
DC  
0.4  
7.9  
0.2  
μV p-p  
nV/√Hz  
pA/√Hz  
μV/V  
8.5  
CS  
0.01  
−120  
f = 100 kHz  
dB  
1 Typical values cover all parts within one standard deviation of the average value. Average values given in many competitor data sheets as typical give unrealistically  
low estimates for parameters that can have both positive and negative values.  
Rev. G | Page 4 of 24  
 
OP1177/OP2177/OP4177  
ABSOLUTE MAXIMUM RATINGS  
Table 3.  
THERMAL RESISTANCE  
θJA is specified for the worst-case conditions, that is, a device  
soldered in a circuit board for surface-mount packages.  
Parameter  
Rating  
Supply Voltage  
36 V  
Input Voltage  
VS− to VS+  
Supply Voltage  
Table 4. Thermal Resistance  
Package Type  
8-Lead MSOP (RM-8)1  
8-Lead SOIC_N (R-8)  
14-Lead SOIC_N (R-14)  
14-Lead TSSOP (RU-14)  
Differential Input Voltage  
Storage Temperature Range  
R, RM, and RU Packages  
Operating Temperature Range  
OP1177/OP2177/OP4177  
Junction Temperature Range  
R, RM, and RU Packages  
Lead Temperature, Soldering (10 sec)  
θJA  
θJC  
44  
43  
36  
43  
Unit  
°C/W  
°C/W  
°C/W  
°C/W  
190  
158  
120  
240  
−65°C to +150°C  
−40°C to +125°C  
−65°C to +150°C  
300°C  
1 MSOP is available in tape and reel only.  
Stresses above those listed under Absolute Maximum Ratings  
may cause permanent damage to the device. This is a stress  
rating only; functional operation of the device at these or any  
other conditions above those indicated in the operational  
section of this specification is not implied. Exposure to absolute  
maximum rating conditions for extended periods may affect  
device reliability.  
ESD CAUTION  
Rev. G | Page 5 of 24  
 
 
 
OP1177/OP2177/OP4177  
TYPICAL PERFORMANCE CHARACTERISTICS  
1.8  
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
50  
V
= ±15V  
V
= ±15V  
SY  
T = 25°C  
A
SY  
45  
40  
35  
30  
25  
20  
15  
10  
5
SOURCE  
SINK  
0.2  
0
0
–40  
–30  
–20  
–10  
0
10  
20  
30  
40  
0.001  
0.01  
0.1  
1
10  
INPUT OFFSETVOLTAGE (µV)  
LOAD CURRENT (mA)  
Figure 7. Input Offset Voltage Distribution  
Figure 10. Output Voltage to Supply Rail vs. Load Current  
90  
3
2
V
= ±15V  
SY  
V
= ±15V  
SY  
80  
70  
60  
50  
40  
30  
20  
10  
0
1
0
–1  
–2  
–3  
0
50  
100  
–50  
150  
0.05  
0.15  
0.25  
0.35  
0.45  
0.55  
0.65  
TEMPERATURE (°C)  
INPUT OFFSET VOLTAGE DRIFT (µV/°C)  
Figure 8. Input Offset Voltage Drift Distribution  
Figure 11. Input Bias Current vs. Temperature  
140  
120  
100  
80  
60  
50  
40  
30  
20  
10  
0
270  
225  
180  
135  
90  
V
= ±15V  
V
C
R
= ±15V  
= 0  
SY  
SY  
L
L
=
GAIN  
60  
PHASE  
45  
40  
0
20  
–10  
–20  
–45  
–90  
0
0
0.1  
0.2  
0.3  
0.4  
0.5  
0.6  
0.7  
100k  
1M  
10M  
INPUT BIAS CURRENT (nA)  
FREQUENCY (Hz)  
Figure 9. Input Bias Current Distribution  
Figure 12. Open-Loop Gain and Phase Shift vs. Frequency  
Rev. G | Page 6 of 24  
 
OP1177/OP2177/OP4177  
120  
100  
80  
V
= ±15V  
= 1,000pF  
= 2k  
= 100mV  
= 1  
SY  
V
V
C
R
= ±15V  
= 4mV p-p  
= 0  
SY  
IN  
C
R
V
L
L
L
L
IN  
=
A
V
60  
A
A
= 100  
= 10  
V
40  
V
20  
0
A
= 1  
V
–20  
–40  
–60  
–80  
GND  
1k  
10k  
100k  
1M  
10M  
100M  
TIME (100µs/DIV)  
FREQUENCY (Hz)  
Figure 16. Small Signal Transient Response  
Figure 13. Closed-Loop Gain vs. Frequency  
50  
45  
40  
35  
30  
25  
20  
15  
10  
500  
V
V
= ±15V  
= 50mV p-p  
V
R
= ±15V  
= 2k  
= 100mV p-p  
SY  
IN  
SY  
450  
400  
350  
300  
250  
200  
150  
100  
L
V
IN  
A
= 1  
V
A
= 10  
V
+OS  
A
= 100  
V
–OS  
5
0
50  
0
1
10k  
10  
100  
CAPACITANCE (pF)  
1k  
1k  
10k  
FREQUENCY (Hz)  
100k  
1M  
100  
Figure 14. Output Impedance vs. Frequency  
Figure 17. Small Signal Overshoot vs. Load Capacitance  
V
C
R
= ±15V  
= 300pF  
= 2kΩ  
= 4V  
= 1  
V
= ±15V  
= 10k  
= –100  
SY  
SY  
R
A
V
L
L
V
L
OUTPUT  
V
= 200mV  
IN  
IN  
0V  
A
V
–15V  
+200mV  
0V  
GND  
INPUT  
TIME (100µs/DIV)  
TIME (10µs/DIV)  
Figure 18. Positive Overvoltage Recovery  
Figure 15. Large Signal Transient Response  
Rev. G | Page 7 of 24  
 
OP1177/OP2177/OP4177  
V
= ±15V  
SY  
OUTPUT  
15V  
0V  
V
R
A
= ±15V  
= 10kΩ  
= –100  
SY  
L
V
V
= 200mV  
IN  
0V  
–200mV  
INPUT  
TIME (4µs/DIV)  
TIME (1s/DIV)  
Figure 19. Negative Overvoltage Recovery  
Figure 22. 0.1 Hz to 10 Hz Input Voltage Noise  
18  
16  
14  
12  
10  
8
140  
120  
100  
80  
V
= ±15V  
V
= ±15V  
SY  
SY  
60  
40  
6
20  
4
0
2
10  
100  
1k  
10k  
100k  
1M  
10M  
0
50  
100  
150  
200  
250  
FREQUENCY (Hz)  
FREQUENCY (Hz)  
Figure 20. CMRR vs. Frequency  
Figure 23. Voltage Noise Density vs. Frequency  
35  
30  
25  
20  
15  
10  
5
140  
120  
100  
80  
V
= ±15V  
SY  
V
= ±15V  
SY  
+I  
SC  
–I  
SC  
–PSRR  
+PSRR  
60  
40  
20  
0
0
–50  
10  
100  
1k  
10k  
100k  
1M  
10M  
0
50  
TEMPERATURE (°C)  
100  
150  
FREQUENCY (Hz)  
Figure 21. PSRR vs. Frequency  
Figure 24. Short-Circuit Current vs. Temperature  
Rev. G | Page 8 of 24  
 
OP1177/OP2177/OP4177  
14.40  
14.35  
14.30  
14.25  
14.20  
14.15  
133  
132  
131  
130  
V
= ±15V  
SY  
V
= ±15V  
SY  
+V  
OH  
129  
128  
127  
–V  
OL  
126  
14.10  
14.05  
14.00  
125  
124  
123  
–50  
0
50  
TEMPERATURE (°C)  
100  
150  
140  
150  
–50  
0
50  
100  
150  
150  
40  
TEMPERATURE (°C)  
Figure 25. Output Voltage Swing vs. Temperature  
Figure 28. CMRR vs. Temperature  
0.5  
0.4  
133  
132  
131  
130  
V
= ±15V  
V
= ±15V  
SY  
SY  
0.3  
0.2  
0.1  
129  
128  
127  
0
–0.1  
–0.2  
–0.3  
–0.4  
–0.5  
126  
125  
124  
123  
20  
40  
60  
80  
100  
120  
0
–50  
0
50  
100  
TIME FROM POWER SUPPLY TURN-ON (Sec)  
TEMPERATURE (°C)  
Figure 26. Warm-Up Drift  
Figure 29. PSRR vs. Temperature  
18  
50  
V
= ±15V  
V
= ±5V  
SY  
SY  
45  
40  
35  
30  
25  
16  
14  
12  
10  
8
6
20  
15  
4
10  
5
2
0
0
–50  
0
50  
100  
–40  
–30  
–20  
–10  
0
10  
20  
30  
TEMPERATURE (°C)  
INPUT OFFSET VOLTAGE (µV)  
Figure 27. Input Offset Voltage vs. Temperature  
Figure 30. Input Offset Voltage Distribution  
Rev. G | Page 9 of 24  
OP1177/OP2177/OP4177  
1.4  
500  
450  
400  
350  
300  
250  
200  
150  
100  
V
T
= ±5V  
V
V
= ±5V  
= 50mV p-p  
SY  
= 25°C  
SY  
IN  
A
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
SINK  
SOURCE  
A
= 1  
A
= 100  
V
V
A
= 10  
V
50  
0
100  
1M  
1k  
10k  
FREQUENCY (Hz)  
100k  
0.01  
0.1  
LOAD CURRENT (mA)  
1
0.001  
10  
Figure 31. Output Voltage to Supply Rail vs. Load Current  
Figure 34. Output Impedance vs. Frequency  
60  
50  
270  
225  
180  
135  
90  
V
C
R
V
A
= ±5V  
= 300pF  
= 2kΩ  
= 1V  
SY  
V
C
R
= ±5V  
= 0  
SY  
L
L
L
=
L
IN  
40  
= 1  
V
30  
GAIN  
20  
PHASE  
10  
45  
GND  
0
0
–10  
–45  
–90  
–20  
100k  
1M  
10M  
TIME (100µs/DIV)  
FREQUENCY (Hz)  
Figure 32. Open-Loop Gain and Phase Shift vs. Frequency  
Figure 35. Large Signal Transient Response  
120  
100  
80  
V
C
R
V
= ±5V  
= 1,000pF  
= 2kΩ  
= 100mV  
= 1  
SY  
V
V
C
R
= ±5V  
= 4mV p-p  
= 0  
SY  
IN  
L
L
L
L
IN  
=
A
V
60  
A
A
= 100  
= 10  
V
40  
V
20  
0
A
= 1  
V
–20  
–40  
–60  
–80  
GND  
1k  
10k  
100k  
1M  
10M  
100M  
TIME (10µs/DIV)  
FREQUENCY (Hz)  
Figure 36. Small Signal Transient Response  
Figure 33. Closed-Loop Gain vs. Frequency  
Rev. G | Page 10 of 24  
OP1177/OP2177/OP4177  
50  
45  
40  
35  
30  
25  
20  
15  
10  
V
A
R
= ±5V  
= 1  
= 10k  
S
V
R
V
= ±5V  
= 2k  
= 100mV  
SY  
V
L
INPUT  
L
IN  
GND  
+OS  
OUTPUT  
–OS  
5
0
1
10k  
10  
100  
CAPACITANCE (pF)  
1k  
TIME (200µs/DIV)  
Figure 40. No Phase Reversal  
Figure 37. Small Signal Overshoot vs. Load Capacitance  
140  
120  
100  
80  
V
R
A
= ±5V  
= 10kΩ  
= –100  
SY  
V
= ±5V  
SY  
L
V
OUTPUT  
V
= 200mV  
IN  
0V  
–15V  
60  
+200mV  
0V  
40  
INPUT  
20  
0
10  
100  
1k  
10k  
100k  
1M  
10M  
TIME (4µs/DIV)  
FREQUENCY (Hz)  
Figure 41. CMRR vs. Frequency  
Figure 38. Positive Overvoltage Recovery  
200  
180  
160  
140  
120  
100  
80  
V
R
A
= ±5V  
= 10k  
= –100  
V
SY  
= ±5V  
SY  
L
V
V
= 200mV  
OUTPUT  
INPUT  
IN  
5V  
0V  
–PSRR  
0V  
60  
+PSRR  
40  
–200mV  
20  
0
10  
100  
1k  
10k  
100k  
1M  
10M  
TIME (4µs/DIV)  
FREQUENCY (Hz)  
Figure 42. PSRR vs. Frequency  
Figure 39. Negative Overvoltage Recovery  
Rev. G | Page 11 of 24  
OP1177/OP2177/OP4177  
4.40  
4.35  
4.30  
4.25  
4.20  
4.15  
V
= ±5V  
SY  
V
= ±5V  
SY  
+V  
OH  
–V  
OL  
4.10  
4.05  
4.00  
–50  
0
50  
TEMPERATURE (°C)  
100  
150  
150  
150  
TIME (1s/DIV)  
Figure 43. 0.1 Hz to 10 Hz Input Voltage Noise  
Figure 46. Output Voltage Swing vs. Temperature  
18  
16  
14  
12  
10  
8
25  
V
= ±5V  
V
= ±5V  
SY  
SY  
20  
15  
10  
6
5
0
4
2
–50  
0
50  
100  
0
50  
100  
150  
200  
250  
FREQUENCY (Hz)  
TEMPERATURE (°C)  
Figure 44. Voltage Noise Density vs. Frequency  
Figure 47. Input Offset Voltage vs. Temperature  
35  
30  
25  
20  
15  
10  
5
600  
V
= ±5V  
SY  
500  
400  
300  
V
= ±15V  
+I  
SY  
SC  
–I  
SC  
V
= ±5V  
SY  
200  
100  
0
0
–50  
0
50  
TEMPERATURE (°C)  
100  
150  
–50  
0
50  
TEMPERATURE (°C)  
100  
Figure 45. Short-Circuit Current vs. Temperature  
Figure 48. Supply Current vs. Temperature  
Rev. G | Page 12 of 24  
OP1177/OP2177/OP4177  
450  
0
T
= 25°C  
A
400  
350  
300  
250  
–20  
–40  
–60  
–80  
200  
150  
–100  
–120  
–140  
–160  
100  
50  
0
0
5
10  
15  
20  
25  
30  
35  
10  
100  
1k  
10k  
100k  
1M  
FREQUENCY (Hz)  
SUPPLY VOLTAGE (V)  
Figure 50. Channel Separation vs. Frequency  
Figure 49. Supply Current vs. Supply Voltage  
Rev. G | Page 13 of 24  
OP1177/OP2177/OP4177  
FUNCTIONAL DESCRIPTION  
The OPx177 series is the fourth generation of Analog Devices,  
Inc., industry-standard OP07 amplifier family. OPx177 is a high  
precision, low noise operational amplifier with a combination of  
extremely low offset voltage and very low input bias currents.  
Unlike JFET amplifiers, the low bias and offset currents are  
relatively insensitive to ambient temperatures, even up to 125°C.  
For RS < 3.9 kꢁ, en dominates and  
n,TOTAL en  
e
For 3.9 kꢁ < RS < 412 kꢁ, voltage noise of the amplifier, the  
current noise of the amplifier translated through the source  
resistor, and the thermal noise from the source resistor all  
contribute to the total noise.  
Analog Devices proprietary process technology and linear design  
expertise has produced a high voltage amplifier with superior  
performance to the OP07, OP77, and OP177 in a tiny MSOP  
8­lead package. Despite its small size, the OPx177 offers numerous  
improvements, including low wideband noise, very wide input  
and output voltage range, lower input bias current, and complete  
freedom from phase inversion.  
For RS > 412 kꢁ, the current noise dominates and  
en,TOTAL inRS  
The total equivalent rms noise over a specific bandwidth is  
expressed as  
e n  
=
(
e n , TOTAL  
)
BW  
OPx177 has a specified operating temperature range as wide as  
any similar device in a plastic surface-mount package. This is  
increasingly important as PCB and overall system sizes continue  
to shrink, causing internal system temperatures to rise. Power  
consumption is reduced by a factor of four from the OP177, and  
bandwidth and slew rate increase by a factor of two. The low  
power dissipation and very stable performance vs. temperature  
also act to reduce warmup drift errors to insignificant levels.  
where BW is the bandwidth in hertz.  
The preceding analysis is valid for frequencies larger than 50 Hz.  
When considering lower frequencies, flicker noise (also known  
as 1/f noise) must be taken into account.  
For a reference on noise calculations, refer to the Band-Pass  
KRC or Sallen-Key Filter section.  
Open-loop gain linearity under heavy loads is superior to compet-  
itive parts, such as the OPA277, improving dc accuracy and  
reducing distortion in circuits with high closed-loop gains.  
Inputs are internally protected from overvoltage conditions  
referenced to either supply rail.  
GAIN LINEARITY  
Gain linearity reduces errors in closed-loop configurations. The  
straighter the gain curve, the lower the maximum error over the  
input signal range. This is especially true for circuits with high  
closed-loop gains.  
Like any high performance amplifier, maximum performance is  
achieved by following appropriate circuit and PCB guidelines.  
The following sections provide practical advice on getting the  
most out of the OPx177 under a variety of application conditions.  
The OP1177 has excellent gain linearity even with heavy loads,  
as shown in Figure 51. Compare its performance to the OPA277,  
shown in Figure 52. Both devices are measured under identical  
conditions, with RL = 2 kꢁ. The OP2177 (dual) has virtually no  
distortion at lower voltages. Compared to the OPA277 at several  
supply voltages and various loads, OP1177 performance far  
exceeds that of its counterpart.  
TOTAL NOISE-INCLUDING SOURCE RESISTORS  
The low input current noise and input bias current of the OPx177  
make it useful for circuits with substantial input source resistance.  
Input offset voltage increases by less than 1 ꢀV maximum per  
500 ꢁ of source resistance.  
V
= ±15V  
SY  
R
= 2k  
L
The total noise density of the OPx177 is  
inRS  
2 + 4kTRS  
)
2
en,TOTAL = en +  
(
OP1177  
where:  
en is the input voltage noise density.  
in is the input current noise density.  
RS is the source resistance at the noninverting terminal.  
k is Boltzmann’s constant (1.38 × 10−23 J/K).  
T is the ambient temperature in Kelvin (T = 273 + temperature  
in degrees Celsius).  
(5V/DIV)  
Figure 51. Gain Linearity  
Rev. G | Page 14 of 24  
 
 
 
 
OP1177/OP2177/OP4177  
V
= ±15V  
V
SY  
=
10V  
SY  
R
= 2kΩ  
A
V
= 1  
L
V
IN  
V
OUT  
OPA277  
TIME (400µs/DIV)  
(5V/DIV)  
Figure 53. No Phase Reversal  
Figure 52. Gain Linearity  
SETTLING TIME  
INPUT OVERVOLTAGE PROTECTION  
Settling time is defined as the time it takes an amplifier output  
to reach and remain within a percentage of its final value after  
application of an input pulse. It is especially important in measure-  
ment and control circuits in which amplifiers buffer ADC inputs  
or DAC outputs.  
When input voltages exceed the positive or negative supply  
voltage, most amplifiers require external resistors to protect  
them from damage.  
The OPx177 has internal protective circuitry that allows voltages as  
high as 2.5 V beyond the supplies to be applied at the input of  
either terminal without any harmful effects.  
To minimize settling time in amplifier circuits, use proper  
bypassing of power supplies and an appropriate choice of circuit  
components. Resistors should be metal film types, because they  
have less stray capacitance and inductance than their wire-wound  
counterparts. Capacitors should be polystyrene or polycarbonate  
types to minimize dielectric absorption.  
Use an additional resistor in series with the inputs if the voltage  
exceeds the supplies by more than 2.5 V. The value of the resistor  
can be determined from the formula  
(
VIN VS  
RS + 500 Ω  
)
5 mA  
The leads from the power supply should be kept as short as  
possible to minimize capacitance and inductance. The OPx177  
has a settling time of about 45 ꢀs to 0.01% (1 mV) with a 10 V  
step applied to the input in a noninverting unity gain.  
With the OPx177 low input offset current of <1 nA maximum,  
placing a 5 kꢁ resistor in series with both inputs adds less than  
5 ꢀV to input offset voltage and has a negligible impact on the  
overall noise performance of the circuit.  
OVERLOAD RECOVERY TIME  
Overload recovery is defined as the time it takes the output  
voltage of an amplifier to recover from a saturated condition to  
its linear response region. A common example is one in which  
the output voltage demanded by the transfer function of the  
circuit lies beyond the maximum output voltage capability of  
the amplifier. A 10 V input applied to an amplifier in a closed-  
loop gain of 2 demands an output voltage of 20 V. This is beyond  
the output voltage range of the OPx177 when operating at 15 V  
supplies and forces the output into saturation.  
5 kꢁ protects the inputs to more than 27 V beyond either supply.  
Refer to the THD + Noise section for additional information on  
noise vs. source resistance.  
OUTPUT PHASE REVERSAL  
Phase reversal is defined as a change of polarity in the amplifier  
transfer function. Many operational amplifiers exhibit phase  
reversal when the voltage applied to the input is greater than the  
maximum common-mode voltage. In some instances, this can  
cause permanent damage to the amplifier. In feedback loops, it  
can result in system lockups or equipment damage. The OPx177  
is immune to phase reversal problems even at input voltages  
beyond the supplies.  
Recovery time is important in many applications, particularly  
where the operational amplifier must amplify small signals in  
the presence of large transient voltages.  
Rev. G | Page 15 of 24  
 
 
 
 
OP1177/OP2177/OP4177  
R2  
100k  
Figure 56 is a scope shot of the output of the OPx177 in response  
to a 400 mV pulse. The load capacitance is 2 nF. The circuit is  
configured in positive unity gain, the worst-case condition for  
stability.  
V+  
R1  
1kΩ  
7
2
3
V
OUT  
6
+
200mV  
OP1177  
10kΩ  
As shown in Figure 58, placing an R-C network parallel to the  
load capacitance (CL) allows the amplifier to drive higher values  
of CL without causing oscillation or excessive overshoot.  
4
V–  
Figure 54. Test Circuit for Overload Recovery Time  
There is no ringing, and overshoot is reduced from 27% to 5%  
using the snubber network.  
Figure 18 shows the positive overload recovery time of the  
OP1177. The output recovers in less than 4 ꢀs after being  
overdriven by more than 100%.  
Optimum values for RS and CS are tabulated in Table 5 for several  
capacitive loads, up to 200 nF. Values for other capacitive loads can  
be determined experimentally.  
The negative overload recovery of the OP1177 is 1.4 ꢀs, as seen  
in Figure 19.  
Table 5. Optimum Values for Capacitive Loads  
THD + NOISE  
CL  
RS  
CS  
The OPx177 has very low total harmonic distortion. This indicates  
excellent gain linearity and makes the OPx177 a great choice for  
high closed-loop gain precision circuits.  
10 nF  
50 nF  
200 nF  
20 Ω  
30 Ω  
200 Ω  
0.33 ꢀF  
6.8 nF  
0.47 ꢀF  
Figure 55 shows that the OPx177 has approximately 0.00025%  
distortion in unity gain, the worst-case configuration for distortion.  
V
R
C
= ±5V  
= 10k  
= 2nF  
SY  
0.1  
L
L
V
= ±15V  
SY  
R
= 10k  
L
BW = 22kHz  
0.01  
0.001  
0
GND  
TIME (10µs/DIV)  
0.0001  
100  
1k  
20  
6k  
Figure 56. Capacitive Load Drive Without Snubber  
FREQUENCY (Hz)  
Figure 55. THD + N vs. Frequency  
CAPACITIVE LOAD DRIVE  
V
= ±5V  
= 10kΩ  
= 200Ω  
= 2nF  
SY  
R
R
C
C
L
S
L
S
OPx177 is inherently stable at all gains and capable of driving  
large capacitive loads without oscillation. With no external  
compensation, the OPx177 safely drives capacitive loads up to  
1000 pF in any configuration. As with virtually any amplifier,  
driving larger capacitive loads in unity gain requires additional  
circuitry to assure stability.  
= 0.47µF  
GND  
In this case, a snubber network is used to prevent oscillation  
and reduce the amount of overshoot. A significant advantage of  
this method is that it does not reduce the output swing because  
the Resistor RS is not inside the feedback loop.  
TIME (10µs/DIV)  
Figure 57. Capacitive Load Drive with Snubber  
Rev. G | Page 16 of 24  
 
 
 
 
 
 
OP1177/OP2177/OP4177  
C
f
V+  
7
2
3
R1  
R2  
V+  
6
V
OUT  
OP1177  
R
+
S
400mV  
C
L
4
+
C
S
7
2
3
V1  
V–  
6
V
OUT  
C
t
OP1177  
Figure 58. Snubber Network Configuration  
4
Caution: The snubber technique cannot recover the loss of  
bandwidth induced by large capacitive loads.  
V–  
Figure 60. Compensation Using Feedback Capacitor  
STRAY INPUT CAPACITANCE COMPENSATION  
REDUCING ELECTROMAGNETIC INTERFERENCE  
The effective input capacitance in an operational amplifier  
circuit (Ct) consists of three components. These are the internal  
differential capacitance between the input terminals, the internal  
common-mode capacitance of each input to ground, and the  
external capacitance including parasitic capacitance. In the  
circuit in Figure 59, the closed-loop gain increases as the signal  
frequency increases.  
A number of methods can be utilized to reduce the effects of  
EMI on amplifier circuits.  
In one method, stray signals on either input are coupled to the  
opposite input of the amplifier. The result is that the signal is  
rejected according to the CMRR of the amplifier.  
This is usually achieved by inserting a capacitor between the inputs  
of the amplifier, as shown in Figure 61. However, this method can  
also cause instability, depending on the value of capacitance.  
The transfer function of the circuit is  
R2  
R1  
1+  
(
1+ sCt R1  
)
R1  
R2  
V+  
indicating a zero at  
+
7
2
3
R2 + R1  
s =  
1
V1  
=
6
V
OUT  
OP1177  
R2R1Ct  
2π  
(
R1/R2  
)
Ct  
C
4
Depending on the value of R1 and R2, the cutoff frequency of  
the closed-loop gain can be well below the crossover frequency.  
In this case, the phase margin (ΦM) can be severely degraded,  
resulting in excessive ringing or even oscillation.  
V–  
Figure 61. EMI Reduction  
Placing a resistor in series with the capacitor (see Figure 62)  
increases the dc loop gain and reduces the output error. Positioning  
the breakpoint (introduced by R-C) below the secondary pole of  
the operational amplifier improves the phase margin and,  
therefore, stability.  
A simple way to overcome this problem is to insert a capacitor  
in the feedback path, as shown in Figure 60.  
The resulting pole can be positioned to adjust the phase margin.  
Setting Cf = (R1/R2) Ct achieves a phase margin of 90°.  
R can be chosen independently of C for a specific phase margin  
according to the formula  
R1  
R2  
R2  
jf2  
R2  
R1  
V+  
R =  
1 +  
+
a
(
)
7
2
3
V1  
6
V
where:  
OUT  
C
t
OP1177  
a is the open-loop gain of the amplifier.  
4
f2 is the frequency at which the phase of a = ΦM − 180°.  
V–  
R2  
Figure 59. Stray Input Capacitance  
V+  
R1  
7
2
+
R
6
V
OUT  
OP1177  
V1  
C
3
4
V–  
Figure 62. Compensation Using Input R-C Network  
Rev. G | Page 17 of 24  
 
 
 
 
 
 
OP1177/OP2177/OP4177  
In the single instrumentation amplifier (see Figure 63), where  
PROPER BOARD LAYOUT  
R4  
R3  
R2  
R1  
The OPx177 is a high precision device. To ensure optimum  
performance at the PCB level, care must be taken in the design  
of the board layout.  
=
R2  
VO =  
(
V2 V1  
)
R1  
To avoid leakage currents, the surface of the board should be  
kept clean and free of moisture. Coating the surface creates a  
barrier to moisture accumulation and helps reduce parasitic  
resistance on the board.  
a mismatch between the ratio R2/R1 and R4/R3 causes the  
common-mode rejection ratio to be reduced.  
To better understand this effect, consider that, by definition,  
Keeping supply traces short and properly bypassing the power  
supplies minimizes power supply disturbances due to output  
current variation, such as when driving an ac signal into a heavy  
load. Bypass capacitors should be connected as closely as possible  
to the device supply pins. Stray capacitances are a concern at the  
outputs and the inputs of the amplifier. It is recommended that  
signal traces be kept at least 5 mm from supply lines to  
minimize coupling.  
ADM  
CMRR =  
ACM  
where ADM is the differential gain and ACM is the common-  
mode gain.  
VO  
VDIFF  
VO  
VCM  
ADM  
=
and ACM =  
1
2
A variation in temperature across the PCB can cause a mismatch in  
the Seebeck voltages at solder joints and other points where dissi-  
milar metals are in contact, resulting in thermal voltage errors. To  
minimize these thermocouple effects, orient resistors so heat  
sources warm both ends equally. Input signal paths should contain  
matching numbers and types of components, where possible to  
match the number and type of thermocouple junctions. For  
example, dummy components such as zero value resistors can  
be used to match real resistors in the opposite input path.  
Matching components should be located in close proximity and  
should be oriented in the same manner. Ensure leads are of equal  
length so that thermal conduction is in equilibrium. Keep heat  
sources on the PCB as far away from amplifier input circuitry as  
is practical.  
VDIFF = V1 V2 andVCM  
=
(
V1 +V2  
)
For this circuit to act as a difference amplifier, its output must  
be proportional to the differential input signal.  
From Figure 63,  
R2  
R1  
R3  
1+  
1+  
R2  
R1  
V = −  
V +  
V2  
1
O
R4  
Arranging terms and combining the previous equations yields  
R4R1+ R3R2 + 2R4R2  
CMRR =  
(1)  
2R4R12R2R3  
The use of a ground plane is highly recommended. A ground  
plane reduces EMI noise and also helps to maintain a constant  
temperature across the circuit board.  
The sensitivity of CMRR with respect to the R1 is obtained by  
taking the derivative of CMRR, in Equation 1, with respect to R1.  
δCMRR  
δR1  
δ
R1R4  
2R2R4 + R2R3  
DIFFERENCE AMPLIFIERS  
=
=
+
δR1 2R1R4 2R2R3 2R1R4 2R2R3  
Difference amplifiers are used in high accuracy circuits to improve  
the common-mode rejection ratio (CMRR).  
δCMRR  
δR1  
1
(
2R2R3)  
R2  
100k  
2 −  
R1R4  
V+  
Assuming that  
7
R1  
2
3
V1  
V2  
6
V
R1 R2 R3 R4 R  
OUT  
OP1177  
4
and  
V–  
R(1 − δ) < R1, R2, R3, R4 < R(1 + δ)  
R3 = R1  
R4 = R1  
R4 R2  
R3 R1  
the worst-case CMRR error arises when  
=
Figure 63. Difference Amplifier  
R1 = R4 = R(1 + δ) and R2 = R3 = R(1 − δ)  
Rev. G | Page 18 of 24  
 
 
 
OP1177/OP2177/OP4177  
V
CC  
Plugging these values into Equation 1 yields  
1
R9  
200k  
C1  
2.2µF  
CMRRMIN  
ADR293  
2δ  
V+  
R3  
47kΩ  
R7  
80.6kΩ  
0.1µF  
where δ is the tolerance of the resistors.  
10µF  
D1  
R6  
50Ω  
Lower tolerance value resistors result in higher common-mode  
rejection (up to the CMRR of the operational amplifier).  
D1  
TR  
R2  
10µF  
R8  
1kΩ  
4.02kΩ  
7
Cu  
2
3
(–)  
6
V
Using 5% tolerance resistors, the highest CMRR that can be  
guaranteed is 20 dB. Alternatively, using 0.1% tolerance resistors  
results in a common-mode rejection ratio of at least 54 dB  
(assuming that the operational amplifier CMRR × 54 dB).  
OUT  
OP1177  
T
V
TC  
J
R5  
100Ω  
TR  
Cu  
(+)  
10µF  
4
10µF  
R1  
50Ω  
R4  
50Ω  
ISOTHERMAL  
BLOCK  
0.1µF  
With the CMRR of OPx177 at 120 dB minimum, the resistor  
match is the limiting factor in most circuits. A trimming resistor  
can be used to further improve resistor matching and CMRR of  
the difference amplifier circuit.  
V–  
Figure 64. Type K Thermocouple Amplifier Circuit  
LOW POWER LINEARIZED RTD  
A common application for a single element varying bridge is an  
RTD thermometer amplifier, as shown in Figure 65. The excita-  
tion is delivered to the bridge by a 2.5 V reference applied at the  
top of the bridge.  
A HIGH ACCURACY THERMOCOUPLE AMPLIFIER  
A thermocouple consists of two dissimilar metal wires placed in  
contact. The dissimilar metals produce a voltage  
VTC = α(TJ TR)  
RTDs may have thermal resistance as high as 0.5°C to 0.8°C  
per mW. To minimize errors due to resistor drift, the current  
through each leg of the bridge must be kept low. In this circuit,  
the amplifier supply current flows through the bridge. However,  
at the OPx177 maximum supply current of 600 ꢀA, the RTD  
dissipates less than 0.1 mW of power, even at the highest resis-  
tance. Errors due to power dissipation in the bridge are kept  
under 0.1°C.  
where:  
TJ is the temperature at the measurement of the hot junction.  
TR is the temperature at the cold junction.  
α is the Seebeck coefficient specific to the dissimilar metals used  
in the thermocouple.  
V
TC is the thermocouple voltage and becomes larger with  
increasing temperature.  
Maximum measurement accuracy requires cold junction compen-  
sation of the thermocouple. To perform the cold junction compen-  
sation, apply a copper wire short across the terminating junctions  
(inside the isothermal block) simulating a 0°C point. Adjust the  
output voltage to zero using the R5 trimming resistor, and remove  
the copper wire.  
Calibration of the bridge is made at the minimum value of  
temperature to be measured by adjusting RP until the output is zero.  
To calibrate the output span, set the full-scale and linearity  
potentiometers to midpoint and apply a 500°C temperature to  
the sensor or substitute the equivalent 500°C RTD resistance.  
Adjust the full-scale potentiometer for a 5 V output. Finally,  
apply 250°C or the equivalent RTD resistance and adjust the  
linearity potentiometer for 2.5 V output. The circuit achieves  
better than 0.5°C accuracy after adjustment.  
The OPx177 is an ideal amplifier for thermocouple circuits  
because it has a very low offset voltage, excellent PSRR and  
CMRR, and low noise at low frequencies.  
It can be used to create a thermocouple circuit with great  
linearity. Resistor R1, Resistor R2, and Diode D1, shown in  
Figure 64, are mounted in an isothermal block.  
Rev. G | Page 19 of 24  
 
 
 
OP1177/OP2177/OP4177  
+15V  
where δ = ΔR/R is the fractional deviation of the RTD resistance  
with respect to the bridge resistance due to the change in temper-  
ature at the RTD.  
500Ω  
200Ω  
0.1µF  
ADR421  
4.37kΩ  
For δ << 1, the preceding expression becomes  
4.12kΩ  
6
V
R2  
R
δ
4.12kΩ  
100Ω  
OUT  
1/2  
OP2177  
7
V ≅  
V
=
O
REF  
R1 R1  
R
5
1+  
+
R2  
100Ω  
20Ω  
R2  
R
R1  
R2  
R1  
R2  
⎞⎛  
⎠⎝  
1+  
+
VREF δ  
⎟⎜  
5kΩ  
49.9kΩ  
100Ω  
RTD  
V+  
8
With VREF constant, the output voltage is linearly proportional  
to δ with a gain factor of  
2
3
R2  
R
R1  
R2  
R1  
R2  
⎠ ⎝  
⎞ ⎛  
1/2  
OP2177  
1
VREF  
1+  
+
V
⎟ ⎜  
OUT  
4
15V  
V–  
R
F
Figure 65. Low Power Linearized RTD Circuit  
0.1µF  
ADR421  
V+  
R
R
R
SINGLE OPERATIONAL AMPLIFIER BRIDGE  
7
2
3
V
The low input offset voltage drift of the OP1177 makes it very  
effective for bridge amplifier circuits used in RTD signal condi-  
tioning. It is often more economical to use a single bridge  
operational amplifier as opposed to an instrumentation amplifier.  
OUT  
6
R(1+δ)  
OP1177  
4
V–  
R
F
In the circuit shown in Figure 66, the output voltage at the  
operational amplifier is  
Figure 66. Single Bridge Amplifier  
R2  
R
δ
R1  
R2  
VO =  
VREF  
R1  
R
+ 1+  
(1+ δ)  
Rev. G | Page 20 of 24  
 
 
 
OP1177/OP2177/OP4177  
REALIZATION OF ACTIVE FILTERS  
BAND-PASS KRC OR SALLEN-KEY FILTER  
CHANNEL SEPARATION  
The low offset voltage and the high CMRR of the OPx177 make  
it an excellent choice for precision filters, such as the band-pass  
KRC filter shown in Figure 67. This filter type offers the capability  
to tune the gain and the cutoff frequency independently.  
Multiple amplifiers on a single die are often required to reject  
any signals originating from the inputs or outputs of adjacent  
channels. OP2177 input and bias circuitry is designed to prevent  
feedthrough of signals from one amplifier channel to the other.  
As a result, the OP2177 has an impressive channel separation of  
greater than −120 dB for frequencies up to 100 kHz and greater  
than −115 dB for signals up to 1 MHz.  
Because the common-mode voltage into the amplifier varies with  
the input signal in the KRC filter circuit, a high CMRR is required  
to minimize distortion. Also, the low offset voltage of the OPx177  
allows a wider dynamic range when the circuit gain is chosen to  
be high.  
C3  
680pF  
R2  
10k  
The circuit of Figure 67 consists of two stages. The first stage is  
a simple high-pass filter where the corner frequency (fC) is  
V+  
2
3
1
8
1/2  
OP2177  
1
6
5
(2)  
V
R3  
33kΩ  
R4  
33kΩ  
OUT  
2π C1C2R1R2  
1/2  
OP2177  
7
C2  
10nF  
C1  
10nF  
C4  
330pF  
and  
4
+
V1  
R1  
20kΩ  
V–  
R1  
(3)  
Q = K  
R2  
Figure 67. Two-Stage, Band-Pass KRC Filter  
where K is the dc gain.  
Choosing equal capacitor values minimizes the sensitivity and  
simplifies Equation 2 to  
10kΩ  
V+  
1
8
100Ω  
6
5
2
3
1/2  
OP2177  
2πC R1R2  
1/2  
OP2177  
7
1
4
The value of Q determines the peaking of the gain vs. frequency  
(ringing in transient response). Commonly chosen values for Q  
are generally near unity.  
+
V1  
50mV  
V–  
Figure 68. Channel Separation Test Circuit  
1
Setting Q =  
yields minimum gain peaking and minimum  
REFERENCES ON NOISE DYNAMICS  
AND FLICKER NOISE  
2
ringing. Determine values for R1 and R2 by using Equation 3.  
S. Franco, Design with Operational Amplifiers and Analog  
Integrated Circuits. McGraw-Hill, 1998.  
1
For  
R1/R2 = 2 in the circuit example. Select R1 = 5 kꢁ  
,
Q =  
2
Analog Devices, Inc., The Best of Analog Dialogue, 1967 to  
1991. Analog Devices, Inc., 1991.  
and R2 = 10 kꢁ for simplicity.  
The second stage is a low-pass filter where the corner frequency  
can be determined in a similar fashion. For R3 = R4 = R  
1
1
2
C3  
C4  
fC  
=
and Q =  
C3  
C4  
2πR  
Rev. G | Page 21 of 24  
 
 
 
 
OP1177/OP2177/OP4177  
OUTLINE DIMENSIONS  
5.00 (0.1968)  
4.80 (0.1890)  
8
1
5
4
6.20 (0.2441)  
5.80 (0.2284)  
4.00 (0.1574)  
3.80 (0.1497)  
0.50 (0.0196)  
0.25 (0.0099)  
1.27 (0.0500)  
BSC  
45°  
1.75 (0.0688)  
1.35 (0.0532)  
0.25 (0.0098)  
0.10 (0.0040)  
8°  
0°  
0.51 (0.0201)  
0.31 (0.0122)  
COPLANARITY  
0.10  
1.27 (0.0500)  
0.40 (0.0157)  
0.25 (0.0098)  
0.17 (0.0067)  
SEATING  
PLANE  
COMPLIANT TO JEDEC STANDARDS MS-012-AA  
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS  
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR  
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.  
Figure 69. 8-Lead Standard Small Outline Package [SOIC_N]  
Narrow Body  
(R-8)  
Dimensions shown in millimeters and (inches)  
8.75 (0.3445)  
8.55 (0.3366)  
8
7
14  
1
6.20 (0.2441)  
5.80 (0.2283)  
4.00 (0.1575)  
3.80 (0.1496)  
1.27 (0.0500)  
0.50 (0.0197)  
0.25 (0.0098)  
45°  
BSC  
1.75 (0.0689)  
1.35 (0.0531)  
0.25 (0.0098)  
0.10 (0.0039)  
8°  
0°  
COPLANARITY  
0.10  
SEATING  
PLANE  
1.27 (0.0500)  
0.40 (0.0157)  
0.51 (0.0201)  
0.31 (0.0122)  
0.25 (0.0098)  
0.17 (0.0067)  
COMPLIANT TO JEDEC STANDARDS MS-012-AB  
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS  
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR  
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.  
Figure 70. 14-Lead Standard Small Outline Package [SOIC_N]  
Narrow Body  
(R-14)  
Dimensions shown in millimeters and (inches)  
Rev. G | Page 22 of 24  
 
OP1177/OP2177/OP4177  
3.20  
3.00  
2.80  
8
1
5
4
5.15  
4.90  
4.65  
3.20  
3.00  
2.80  
PIN 1  
IDENTIFIER  
0.65 BSC  
0.95  
0.85  
0.75  
15° MAX  
1.10 MAX  
0.80  
0.55  
0.40  
0.15  
0.05  
0.23  
0.09  
6°  
0°  
0.40  
0.25  
COPLANARITY  
0.10  
COMPLIANT TO JEDEC STANDARDS MO-187-AA  
Figure 71. 8-Lead Mini Small Outline Package [MSOP]  
(RM-8)  
Dimensions shown in millimeters  
5.10  
5.00  
4.90  
14  
8
4.50  
4.40  
4.30  
6.40  
BSC  
1
7
PIN 1  
0.65 BSC  
1.05  
1.00  
0.80  
1.20  
MAX  
0.20  
0.09  
0.75  
0.60  
0.45  
8°  
0°  
0.15  
0.05  
COPLANARITY  
0.10  
SEATING  
PLANE  
0.30  
0.19  
COMPLIANT TO JEDEC STANDARDS MO-153-AB-1  
Figure 72. 14-Lead Thin Shrink Small Outline Package [TSSOP]  
(RU-14)  
Dimensions shown in millimeters  
Rev. G | Page 23 of 24  
OP1177/OP2177/OP4177  
ORDERING GUIDE  
Model  
OP1177AR  
OP1177ARZ1  
OP1177ARZ-REEL1  
OP1177ARZ-REEL71  
OP1177ARM-REEL  
OP1177ARMZ1  
OP1177ARMZ-REEL1  
OP1177ARMZ-R71  
OP2177AR  
Temperature Range  
Package Description  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead MSOP  
8-Lead MSOP  
8-Lead MSOP  
8-Lead MSOP  
Package Option  
R-8  
R-8  
R-8  
R-8  
RM-8  
RM-8  
RM-8  
RM-8  
R-8  
Branding  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
AZA  
AZA#  
AZA#  
AZA#  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead SOIC_N  
8-Lead MSOP  
8-Lead MSOP  
8-Lead MSOP  
8-Lead MSOP  
OP2177AR-REEL  
OP2177AR-REEL7  
OP2177ARZ1  
R-8  
R-8  
R-8  
R-8  
OP2177ARZ-REEL1  
OP2177ARZ-REEL71  
OP2177ARM-REEL  
OP2177ARMZ1  
OP2177ARMZ-REEL1  
OP2177ARMZ-R71  
OP4177AR  
OP4177AR-REEL  
OP4177AR-REEL7  
OP4177ARZ1  
OP4177ARZ-REEL1  
OP4177ARZ-REEL71  
OP4177ARU  
R-8  
RM-8  
RM-8  
RM-8  
RM-8  
R-14  
R-14  
R-14  
R-14  
R-14  
R-14  
RU-14  
RU-14  
RU-14  
RU-14  
B2A  
B2A#  
B2A#  
B2A#  
14-Lead SOIC_N  
14-Lead SOIC_N  
14-Lead SOIC_N  
14-Lead SOIC_N  
14-Lead SOIC_N  
14-Lead SOIC_N  
14-Lead TSSOP  
14-Lead TSSOP  
14-Lead TSSOP  
14-Lead TSSOP  
OP4177ARU-REEL  
OP4177ARUZ1  
OP4177ARUZ-REEL1  
1 Z = RoHS Compliant Part; # denotes Pb-free product may be top or bottom marked.  
©2001–2009 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D02627-0-11/09(G)  
Rev. G | Page 24 of 24  
 

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