Dual/Quad Single-Supply
Operational Amplifiers
OP292/OP492
Data Sheet
PIN CONFIGURATIONS
Single-supply operation: 4.5 V to 33 V
Input common-mode includes ground
Output swings to ground
High slew rate: 3 V/μs
High gain bandwidth: 4 MHz
Low input offset voltage
High open-loop gain
No phase inversion
OUTA
1
–INA 2
OP292
+INA 3
TOP VIEW
–V 4 (Not to Scale)
8
+V
7
OUTB
6
–INB
5
+INB
00310-00
FEATURES
Figure 1. 8-Lead Narrow-Body SOIC (S-Suffix)
14 OUTD
OUTA 1
APPLICATIONS
–INA 2
+INA 3
Disk drives
Mobile phones
Servo controls
Modems and fax machines
Pagers
Power supply monitors and controls
Battery-operated instrumentation
13 –IND
OP492
12 +IND
TOP VIEW
11 –V
(Not to Scale)
10 +INC
+INB 5
–INB 6
9
–INC
OUTB 7
8
OUTC
00310-002
+V 4
Figure 2. 14-Lead Narrow-Body SOIC (S-Suffix)
GENERAL DESCRIPTION
The OP292/OP492 are low cost, general-purpose dual and quad
operational amplifiers designed for single-supply applications
and are ideal for 5 V systems.
Fabricated on Analog Devices, Inc., CBCMOS process, the
OP292/OP492 series has a PNP input stage that allows the input
voltage range to include ground. A BiCMOS output stage enables
the output to swing to ground while sinking current.
The OP292/OP492 series is unity-gain stable and features an
outstanding combination of speed and performance for singleor dual-supply operation. The OP292/OP492 provide a high
slew rate, high bandwidth, with open-loop gain exceeding
40,000 and offset voltage under 0.8 mV (OP292) and 1 mV
(OP492). With these combinations of features and low supply
current, the OP292/OP492 series is an excellent choice for
battery-operated applications.
The OP292/OP492 series performance is specified for single- or
dual-supply voltage operation over the extended industrial
temperature range (−40°C to +125°C).
Rev. D
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OP292/OP492
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Typical Applications ....................................................................... 14
Applications ....................................................................................... 1
Direct Access Arrangement for Telephone Line Interface ... 14
Pin Configurations ........................................................................... 1
Single-Supply Instrumentation Amplifier .............................. 14
General Description ......................................................................... 1
DAC Output Amplifier .............................................................. 14
Revision History ............................................................................... 2
50 Hz/60 Hz Single-Supply Notch Filter ................................. 15
Specifications..................................................................................... 3
Four-Pole Bessel Low-Pass Filter ............................................. 15
Electrical Characteristics ............................................................. 3
Low Cost, Linearized Thermistor Amplifier.............................. 15
Absolute Maximum Ratings............................................................ 6
Thermal Resistance ...................................................................... 6
Single-Supply Ultrasonic Clamping/Limiting Receiver
Amplifier ..................................................................................... 16
ESD Caution .................................................................................. 6
Precision Single-Supply Voltage Comparator ........................ 16
Typical Performance Characteristics ............................................. 7
Programmable Precision Window Comparator .................... 16
Applications Information .............................................................. 13
Outline Dimensions ....................................................................... 17
Phase Reversal ............................................................................. 13
Ordering Guide .......................................................................... 17
Power Supply Considerations ................................................... 13
REVISION HISTORY
8/15—Rev. C to Rev. D
Change to General Description Section ........................................ 1
Changes to Ordering Guide .......................................................... 17
5/09—Rev. B to Rev. C
Deleted 8-Lead PDIP and 14-Lead PDIP ........................ Universal
Changes to Features Section and General Description Section . 1
Changed VS = 5 V to VS = ±15 V .................................................... 4
Changes to Table 3 and Table 4 ....................................................... 6
Changes to Figure 21 Caption and Figure 24 Caption .............. 10
Changes to Figure 29 ...................................................................... 11
Changes to Figure 35 ...................................................................... 13
Deleted OP292 SPICE Macro-Model Section ............................ 14
Changes to Figure 38 ...................................................................... 14
Changes to Figure 39 and Figure 41............................................. 15
Deleted OP492 SPICE Macro-Model Section ............................ 16
Changes to Figure 44...................................................................... 16
Updated Outline Dimensions ....................................................... 17
Changes to Ordering Guide .......................................................... 17
10/02—Rev. A to Rev. B
Edits to Outline Dimensions......................................................... 18
1/02—Rev. 0 to Rev. A
Deleted Wafer Test Limits ................................................................4
Deleted Dice Characteristics ............................................................4
Edits to Ordering Guide ................................................................ 20
Rev. D | Page 2 of 20
Data Sheet
OP292/OP492
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
VS = 5 V, VCM = 0 V, VO = 2 V, TA = 25°C, unless otherwise noted.
Table 1.
Parameter
INPUT CHARACTERISTICS
Offset Voltage
OP292
Symbol
Conditions
Min
VOS
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
OP492
VOS
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
Input Bias Current
IB
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
Input Offset Current
IOS
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
Input Voltage Range
Common-Mode Rejection Ratio
CMRR
Large Signal Voltage Gain
AVO
Offset Voltage Drift
Long-Term VOS Drift 1
Bias Current Drift
ΔVOS/ΔT
ΔVOS/ΔT
ΔIB/ΔT
Offset Current Drift
ΔIOS/ΔT
OUTPUT CHARACTERISTICS
Output Voltage Swing
High
Low
Short-Circuit Current Limit
POWER SUPPLY
Power Supply Rejection Ratio
Supply Current Per Amp
VOUT
VOUT
VCM = 0 V to 4.0 V
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
RL = 10 kΩ, VO = 0.1 V to 4 V
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
RL = 100 kΩ to GND
−40°C ≤ TA ≤ +125°C
RL = 2 kΩ to GND
−40°C ≤ TA ≤ +125°C
RL = 100 kΩ to V+
−40°C ≤ TA ≤ +125°C
RL = 2 kΩ to V+
−40°C ≤ TA ≤ +125°C
ISC
PSRR
ISY
0
75
70
65
25
10
5
4.0
3.8
3.7
5
VS = 4.5 V to 30 V, VO = 2 V
−40°C ≤ TA ≤ +125°C
VO = 2 V
Rev. D | Page 3 of 20
75
70
Typ
Max
Unit
0.1
0.3
0.5
0.1
0.3
0.5
450
0.75
3.0
7
100
0.4
0.8
1.2
2.5
1
1.5
2.5
700
2.5
5.0
50
700
1.2
4.0
mV
mV
mV
mV
mV
mV
nA
µA
µA
nA
nA
µA
V
dB
dB
dB
V/mV
V/mV
V/mV
µV/°C
µV/Month
pA/°C
pA/°C
pA/°C
pA/°C
95
93
90
200
100
50
2
1
6
400
1.5
2
4.3
4.1
3.9
8
12
280
300
8
95
90
0.8
10
20
20
450
550
1.2
V
V
V
mV
mV
mV
mV
mA
dB
dB
mA
OP292/OP492
Data Sheet
Parameter
Symbol
Conditions
Min
DYNAMIC PERFORMANCE
Slew Rate
SR
RL = 10 kΩ
−40°C ≤ TA ≤ +125°C
1
Gain Bandwidth Product
Phase Margin
Channel Separation
NOISE PERFORMANCE
Voltage Noise
Voltage Noise Density
Current Noise Density
1
GBP
φm
CS
en p-p
en
in
fO = 1 kHz
0.1 Hz to 10 Hz
f = 1 kHz
Typ
Unit
3
2
4
75
100
V/µs
V/µs
MHz
Degrees
dB
25
15
0.7
µV p-p
nV/√Hz
pA/√Hz
Long-term offset voltage drift is guaranteed by 1,000 hours life test performed on three independent wafer lots at 125°C with LTPD of 1.3.
Rev. D | Page 4 of 20
Max
Data Sheet
OP292/OP492
VS =±15 V, VCM = 0 V, VO = 2 V, TA = 25°C, unless otherwise noted.
Table 2.
Parameter
INPUT CHARACTERISTICS
Offset Voltage
OP292
Symbol
Conditions
Min
VOS
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
OP492
VOS
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
Input Bias Current
IB
Input Offset Current
IOS
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
Input Voltage Range 1
Common-Mode Rejection Ratio
CMRR
Large Signal Voltage Gain
AVO
Offset Voltage Drift
Bias Current Drift
OUTPUT CHARACTERISTICS
Output Voltage Swing
ΔVOS/ΔT
ΔIB/ΔT
Short-Circuit Current Limit
POWER SUPPLY
Power Supply Rejection Ratio
ISC
Supply Current Per Amp
DYNAMIC PERFORMANCE
Slew Rate
ISY
Gain Bandwidth Product
Phase Margin
Channel Separation
NOISE PERFORMANCE
Voltage Noise
Voltage Noise Density
Current Noise Density
GBP
φm
CS
1
VO
PSRR
SR
en p-p
en
in
VCM = ±11 V
−40°C ≤ TA ≤ +125°C
RL = 10 kΩ, VO =±10 V
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +125°C
−40°C ≤ TA ≤ +125°C
−11
78
75
25
10
5
Typ
Max
Unit
1.0
1.2
1.5
1.4
1.7
2
375
0.5
7
20
0.4
2.0
2.5
3
2.5
2.8
3
700
1
50
100
1.2
+11
mV
mV
mV
mV
mV
mV
nA
µA
nA
nA
µA
V
dB
dB
V/mV
V/mV
V/mV
µV/°C
pA/°C
100
95
120
75
60
4
3
10
RL = 2 kΩ to GND
−40°C ≤ TA ≤ +125°C
RL = 100 kΩ to GND
−40°C ≤ TA ≤ +125°C
Short circuit to GND
±11
±10
±13.8
±13.5
8
±12.2
±11
±14.3
±14.0
10.5
V
V
V
mV
mA
VS = ±2.25 V to ±15 V
−40°C ≤ TA ≤ +125°C
VO = 0 V
75
70
86
83
1
dB
dB
mA
RL =10 kΩ
−40°C ≤ TA ≤ +125°C
2.5
2
fO = 1 kHz
0.1 Hz to 10 Hz
f = 1 kHz
Input voltage range is guaranteed by CMRR tests.
Rev. D | Page 5 of 20
1.4
4
3
4
75
100
V/µs
V/µs
MHz
Degrees
dB
25
15
0.7
µV p-p
nV/√Hz
pA/√Hz
OP292/OP492
Data Sheet
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 3.
Parameter
Supply Voltage
Input Voltage Range1
Differential Input Voltage1
Output Short-Circuit Duration
Storage Temperature Range
Operating Temperature Range
Junction Temperature Range
Lead Temperature Range (Soldering, 60 sec)
1
Rating
33 V
−15 V to +14 V
V1
Unlimited
−65°C to +150°C
−40°C to +125°C
−65°C to +125°C
300°C
For supply voltages less than 36 V, the absolute maximum input voltage is
equal to the supply voltage.
θJA is specified for the worst-case conditions, that is, a device
soldered in the circuit board for the surface-mount packages.
Table 4. Thermal Resistance
Package Type
8-Lead SOIC
14-Lead SOIC
ESD CAUTION
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
Rev. D | Page 6 of 20
θJA
158
120
θJC
43
36
Unit
°C/W
°C/W
Data Sheet
OP292/OP492
TYPICAL PERFORMANCE CHARACTERISTICS
160
200
VS = 5V
VCM = 0V
TA = 25°C
720 OP AMPS
175
150
120
100
80
60
50
40
25
20
0
–500 –400 –300 –200 –100
0
100 200 300
INPUT OFFSET VOLTAGE, VOS (µV)
00310-003
75
400
0
–0.5 –0.4 –0.3 –0.2 –0.1
0
0.1 0.2 0.3 0.4
INPUT OFFSET VOLTAGE, VOS (mV)
500
Figure 3. OP292 Input Offset Voltage Distribution @ 5 V
0.5
0.6
00310-006
100
2.0
00310-007
UNITS
125
UNITS
VS = 5V
VCM = 0V
TA = 25°C
600 OP AMPS
140
Figure 6. OP492 Input Offset Voltage Distribution @ 5 V
240
320
VS = ±15V
VCM = 0V
TA = 25°C
720 OP AMPS
280
240
VS = ±15V
VCM = 0V
TA = 25°C
600 OP AMPS
200
160
UNITS
UNITS
200
160
120
120
80
80
40
00310-004
40
0
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
INPUT OFFSET VOLTAGE, VOS (mV)
1.8
0
0
2.0
0.8
1.0
1.2
1.4
1.6
1.8
160
VS = 5V
VCM = 0V
–40°C ≤ TA ≤ +125°C
600 OP AMPS
VS = 5V
VCM = 0V
–40°C ≤ TA ≤ +125°C
600 OP AMPS
140
120
100
80
80
60
60
40
40
20
20
0
0
0.4
0.8
1.2
1.6
2.0
2.4
TCVOS (µV/°C)
2.8
3.2
3.6
0
4.0
0
Figure 5. OP292 Temperature Drift (TCVOS) Distribution @ 5 V
0.5
1.0
1.5
2.5
3.0
2.0
TCVOS (µV/°C)
3.5
4.0
4.5
5.0
Figure 8. OP492 Temperature Drift (TCVOS) Distribution @ 5 V
Rev. D | Page 7 of 20
00310-008
UNITS
100
00310-005
UNITS
0.6
Figure 7. OP492 Input Offset Voltage Distribution @ ±15 V
160
120
0.4
INPUT OFFSET VOLTAGE, VOS (mV)
Figure 4. OP292 Input Offset Voltage Distribution @ ±15 V
140
0.2
OP292/OP492
Data Sheet
200
240
VS = 5V
VCM = 0V
–40°C ≤ TA ≤ +125°C
600 OP AMPS
210
180
150
150
120
100
90
75
60
50
30
25
0
0
1
2
3
4
5
TCVOS (µV/°C)
6
7
8
0
0
Figure 9. OP292 Temperature Drift (TCVOS) Distribution @ ±15 V
1
2
3
4
5
TCVOS (µV/°C)
6
7
8
00310-012
UNITS
125
00310-009
UNITS
VS = ±15V
VCM = 0V
–40°C ≤ TA ≤ +125°C
600 OP AMPS
175
Figure 12. OP492 Temperature Drift (TCVOS) Distribution @ ±15 V
900
600
VS = 5V
VO = 4V
800
VS = 5V
VO = 4V
500
RL = 10kΩ
OPEN-LOOP GAIN (V/mV)
OPEN-LOOP GAIN (V/mV)
700
400
300
RL = 10kΩ
200
500
400
300
RL = 2kΩ
200
RL = 2kΩ
100
600
–25
0
25
50
75
100
125
TEMPERATURE (°C)
0
–50
00310-010
0
–50
0
25
50
TEMPERATURE (°C)
75
100
125
Figure 13. OP492 Open-Loop Gain vs. Temperature @ 5 V
Figure 10. OP292 Open-Loop Gain vs. Temperature @ 5 V
400
250
VS = ±15V
VO = ±10V
VS = ±15V
VO = ±10V
350
OPEN-LOOP GAIN (V/mV)
200
150
RL = 10kΩ
100
RL = 2kΩ
300
RL = 10kΩ
250
200
150
RL = 2kΩ
100
50
0
–50
–25
0
25
50
75
100
125
TEMPERATURE (°C)
0
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
125
Figure 14. OP492 Open-Loop Gain vs. Temperature @ ±15 V
Figure 11. OP292 Open-Loop Gain vs. Temperature @ ±15 V
Rev. D | Page 8 of 20
00310-014
50
00310-011
OPEN-LOOP GAIN (V/mV)
–25
00310-013
100
Data Sheet
OP292/OP492
1.2
VS = ±15V
1.0
VS = +5V
0.8
0.6
0.4
0.2
–50
0
–25
25
50
TEMPERATURE (°C)
75
100
125
VS = ±15V
1.0
0.8
VS = +5V
0.6
0.4
0.2
–50
Figure 15. OP292 Supply Current per Amplifier vs. Temperature
–25
0
50
25
TEMPERATURE (°C)
75
100
125
Figure 18. OP492 Supply Current per Amplifier vs. Temperature
6
6
VS = ±15V
VO = ±10V
VS = ±15V
VO = ±10V
+SR
+SR
5
4
SLEW RATE (V/µs)
5
SLEW RATE (V/µs)
1.2
00310-018
SUPPLY CURRENT PER AMPLIFIER (mA)
1.4
00310-015
SUPPLY CURRENT PER AMPLIFIER (mA)
1.4
–SR
+SR
3
2
4
–SR
3
+SR
2
–SR
–SR
1
1
–25
0
25
50
TEMPERATURE (°C)
75
100
125
0
–50
00310-016
0
–50
Figure 16. OP292 Slew Rate vs. Temperature
25
50
TEMPERATURE (°C)
0
75
100
125
Figure 19. OP492 Slew Rate vs. Temperature
90
90
TA = 25°C
V+ = 5V
V– = 0V
RL = 10kΩ
80
70
TA = 25°C
VS = 10kΩ
RL = 10kΩ
80
70
60
60
PHASE
20
90
10
45
0
0
–10
1k
10k
100k
FREQUENCY (Hz)
1M
–45
10M
40
PHASE
MARGIN
= 92°
30
PHASE
20
+90
10
+45
0
0
Figure 17. OP292/OP492 Open-Loop Gain and Phase vs. Frequency @ 5 V
+135
–10
1k
10k
100k
FREQUENCY (Hz)
1M
–45
10M
PHASE (DEGREES)
30
135
PHASE (Degrees)
PHASE
MARGIN
= 83°
00310-020
40
GAIN
50
GAIN (dB)
GAIN
50
00310-017
GAIN (dB)
–25
00310-019
VS = 5V
VO = 0.1V, 4V
VS = 5V
VO = 0.1V, 4V
Figure 20. OP292/OP492 Open-Loop Gain and Phase vs. Frequency @ ±15 V
Rev. D | Page 9 of 20
OP292/OP492
Data Sheet
50
50
TA = 25°C
V+ = 5V
V– = 0V
30
20
10
30
20
10
0
0
100k
10M
1M
FREQUENCY (Hz)
–10
Figure 21. OP292/OP492 Closed-Loop Gain vs. Frequency @ 5 V
1k
100k
1M
10M
FREQUENCY (Hz)
Figure 24. OP292/OP492 Closed-Loop Gain vs. Frequency @ ±15 V
120
120
80
60
40
20
10k
100k
1M
FREQUENCY (Hz)
80
60
40
20
0
100
00310-022
1k
1k
10k
1M
100k
FREQUENCY (Hz)
Figure 22. OP292/OP492 CMR vs. Frequency @ 5 V
Figure 25. OP292/OP492 CMR vs. Frequency @ ±15 V
120
120
80
60
40
20
10k
100k
FREQUENCY (Hz)
1M
80
+PSSR
60
–PSSR
40
20
0
100
00310-023
1k
TA = 25°C
VS = ±15V
100
1k
10k
100k
FREQUENCY (Hz)
Figure 23. OP292/OP492 PSR vs. Frequency @ 5 V
Figure 26. OP292/OP492 PSR vs. Frequency @ ±15 V
Rev. D | Page 10 of 20
1M
00310-026
POWER SUPPLY REJECTION (dB)
TA = 25°C
VS = 5V
100
0
100
TA = 25°C
VS = ±15V
100
00310-025
100
COMMON-MODE REJECTION (dB)
TA = 25°C
V+ = 5V
V– = 0V
0
100
POWER SUPPLY REJECTION (dB)
10k
00310-024
10k
1k
00310-021
–10
COMMON-MODE REJECTION (dB)
TA = 25°C
VS = ±15V
40
CLOSED-LOOP GAIN (dB)
CLOSED-LOOP GAIN (dB)
40
Data Sheet
OP292/OP492
15.0
OUTPUT SWING (V)
4.4
14.0
–OUTPUT SWING (V)
RL = 100kΩ
10.0
RL = 10kΩ
4.2
RL = 2kΩ
3.8
–50
0
–25
25
50
TEMPERATURE (°C)
75
100
125
00310-027
OUTPUT VOLTAGE SWING (V)
4.6
4.0
RL = 100kΩ
VS = ±15V
VS = 5V
Figure 27. OP292/OP492 VOUT Swing vs. Temperature @ 5 V
RL = 10kΩ
13.0
RL = 2kΩ
12.0
11.0
RL = 2kΩ
–14.0
RL = 10kΩ
RL = 100kΩ
–14.5
–15.0
–50
–25
50
25
TEMPERATURE (°C)
0
75
100
125
00310-030
4.8
Figure 30. OP292/OP492 VOUT Swing vs. Temperature @ ±15 V
10
600
VS = ±15V
VCM = 0V
VS = 5V
VCM = 0V
INPUT BIAS CURRENT (nA)
INPUT BIAS CURRENT (µA)
500
OP492
1
OP292
400
OP492
300
OP292
200
–25
0
50
25
TEMPERATURE (°C)
75
100
125
0
–50
00310-028
0.1
–50
Figure 28. OP292/OP492 Input Bias Current vs. Temperature @ 5 V
–25
0
50
25
TEMPERATURE (°C)
100
75
125
00310-031
100
Figure 31. OP292/OP492 Input Bias Current vs. Temperature @ ±15 V
–40
0.50
0.48
0.46
–RAIL
0.44
+15V
0.42
IB CURRENT (nA)
VS = +5V, ±15V
RL = 2kΩ
VO = 3V p-p
–80
–90
–100
0.40
0.38
0.36
A
V
0.34
IN
0.32
0.30
–15V
0.28
0.26
0.24
–110
+RAIL
0.22
–120
0
10
100
1k
10k
FREQUENCY (Hz)
100k
Figure 29. OP292/OP492 Channel Separation
0.18
0
1
2
3
4
5
6
7 8
VIN (V)
9
10 11 12 13 14 15
Figure 32. OP292/OP492 IB Current vs. Common-Mode Voltage
Rev. D | Page 11 of 20
00310-032
0.20
00310-029
CHANNEL SEPARATION (dB)
–60
CH A 800dV FS
0Hz
MKR: 1000Hz
Data Sheet
100dV/DIV
MKR: 16.9µV/Hz
25kHz
BW: 150Hz
00310-033
OP292/OP492
Figure 33. Voltage Noise Density
Rev. D | Page 12 of 20
Data Sheet
OP292/OP492
APPLICATIONS INFORMATION
PHASE REVERSAL
1V/DIV
An input voltage that is as much as 5 V below the negative rail
will not result in phase reversal.
10V p-p
OP492
2kΩ
4ms/DIV
Figure 35. No Negative Rail Phase Reversal, Even with Input Signal
at 5 V Below Ground
The OP292/OP492 are designed to operate equally well at single
+5 V or ±15 V supplies. The lowest supply voltage recommended
is 4.5 V.
100
90
It is a good design practice to bypass the supply pins with a
0.1 µF ceramic capacitor. It helps improve filtering of high
frequency noise.
0V
OP492
2kΩ
10
0%
5µs
Figure 34. Output Phase Reverse If Input Exceeds
the Positive Supply (V+) by More Than 0.9 V
00310-034
11.8V p-p
0V
POWER SUPPLY CONSIDERATIONS
1V
5V
5V
00310-035
The OP492 has built-in protection against phase reversal when
the input voltage goes to either supply rail. In fact, it is safe for
the input to exceed either supply rail by up to 0.6 V with no risk
of phase reversal. However, the input should not go beyond the
positive supply rail by more than 0.9 V; otherwise, the output
will reverse phase. If this condition occurs, the problem can be
fixed by adding a 5 kΩ current limiting resistor in series with
the input pin. With this addition, the input can go to more than
5 V beyond the positive rail without phase reversal.
For dual-supply operation, the negative supply (V−) must be
applied at the same time, or before V+. If V+ is applied before V−,
or in the case of a loss of the V− supply, while either input is
connected to ground or another low impedance source, excessive
input current may result. Potentially damaging levels of input
current can destroy the amplifier. If this condition can exist,
simply add a l kΩ or larger resistor in series with the input to
eliminate the problem.
Rev. D | Page 13 of 20
OP292/OP492
Data Sheet
TYPICAL APPLICATIONS
Figure 36 shows a 5 V single-supply transmit/receive telephone line
interface for a modem circuit. It allows full duplex transmission
of modem signals on a transformer-coupled 600 V line in a
differential manner. The transmit section gain can be set for the
specific modem device output. Similarly, the receive amplifier
gain can be appropriately selected based on the modem device
input requirements. The circuit operates on a single 5 V supply.
The standard value resistors allow the use of a SIP-packaged
resistor array; coupled with a quad op amp in a single package,
this offers a compact, low part count solution.
TX GAIN ADJUST
50kΩ
1:1
20kΩ 0.1µF
300kΩ
1/4
OP492
300kΩ
20kΩ
T1
6.2V
TRANSMIT
TXA
20kΩ
6.2V
MODEM
10µF
20kΩ
5V
20kΩ
1/4
OP492
RX GAIN ADJUST
20kΩ
50kΩ
0.1µF
RECEIVE
RXA
00310-036
0.1µF
1/2
OP292
20kΩ
VREF
7
VOUT
4
1
5kΩ
5kΩ
20kΩ
VOUT = 5 +
RG
40kΩ
RG
+ VREF
Figure 37. Single-Supply Instrumentation Amplifier
In this configuration, the output can swing to near 0 V; however,
be careful because the common-mode voltage range of the input
cannot operate to 0 V. This is because of the limitation of the
circuit configuration where the first amplifier must be able to
swing below ground to attain a 0 V common-mode voltage,
which it cannot do. Depending on the gain of the instrumentation
amplifier, the input common-mode extends to within about 0.3 V
of zero. The worst-case common-mode limit for a given gain
can be easily calculated.
The OP292/OP492 are ideal for buffering the output of singlesupply digital-to-analog converters (DACs). Figure 38 shows a
typical amplifier used to buffer the output of a CMOS DAC
that is connected for single-supply operation. To do that, the
normally current output 12-bit CMOS DAC (R-2R ladder
type) is connected backward to produce a voltage output. This
operating configuration necessitates a low voltage reference. In
this case, a 1.235 V low power reference is used. The relatively
high output impedance (10 kΩ) is buffered by the OP292, and
at the same time, gained up to a much more usable level. The
potentiometer provides an accurate gain trim for a 4.095 V fullscale, allowing 1 mV increment per LSB of control resolution.
5V DC
5kΩ
20kΩ
8
1/2
OP292
DAC OUTPUT AMPLIFIER
1/4
OP492
100pF 5kΩ
5
VIN
20kΩ
Figure 36. Universal Direct Access Arrangement for Telephone Line Interface
The DAC8043 device comes in an 8-lead PDIP package, providing
a cost-effective, compact solution to a 12-bit analog channel.
5V
SINGLE-SUPPLY INSTRUMENTATION AMPLIFIER
A low cost, single-supply instrumentation amplifier can be built
as shown in Figure 37. The circuit uses two op amps to form a
high input impedance differential amplifier. Gain can be set by
selecting resistor RG, which can be calculated using the transfer
function equation. Normally, VREF is set to 0 V. Then the output
voltage is a function of the gain times the differential input voltage.
However, the output can be offset by setting VREF from 0 V to
4 V, as long as the input common-mode voltage of the amplifier
is not exceeded.
1/2
OP292
5V
5V
7.5kΩ
NC
1.235V
AD589
2 RFB
Clk 7
CLK
3 IOUT
Sri 6
SRI
4 GND
LD
VOUT
1mV/LSB
0V – 4.095V
FS
DAC8043
VDD
1 VREF
DD 8
20kΩ
8.45kΩ
5
500kΩ
LD SRI CLK
DIGITAL
CONTROL
Figure 38. 12-Bit Single-Supply DAC with Serial Bus Control
Rev. D | Page 14 of 20
00310-038
TO
TELEPHONE
LINE
5V
00310-037
DIRECT ACCESS ARRANGEMENT FOR TELEPHONE
LINE INTERFACE
Data Sheet
OP292/OP492
Figure 39 shows a notch filter that achieves nearly 30 dB of
60 Hz rejection while powered by only a single 12 V supply.
The circuit also works well on 5 V systems. The filter uses a
twin-T configuration, whose frequency selectivity depends
heavily on the relative matching of the capacitors and resistors in
the twin-T section. Mylar is a good choice for the capacitors of
the twin-T, and the relative matching of the capacitors and resistors
determines the pass-band symmetry of the filter. Using 1%
resistors and 5% capacitors produces satisfactory results.
The amount of rejection and the Q of the filter is solely determined
by one resistor and is shown in the table with Figure 39. The
bottom amplifier is used to split the supply to bias the amplifier
to midlevel. The circuit can be modified to reject 50 Hz by simply
changing the resistors in the twin-T section (R1 through R4)
from 2.67 kΩ to 3.16 kΩ and by changing R5 to ½ of 3.16 kΩ. For
best results, the common value resistors can be from a resistor
array for optimum matching characteristics.
R2
2.67kΩ
R1
2.67kΩ
1/4
OP492
C1
1µF
C2
1µF
12V
1/4
OP492
VIN
R6
100kΩ
R3
2.67kΩ
C3
2µF
(1µF × 2)
12V
R8
100kΩ
R9
100kΩ
R7
1kΩ
RQ
FILTER Q RQ (kΩ ) REJECTION (dB) VOLTAGE GAIN
1.0
40
1.33
1.00
2.0
35
1.50
1.25
3.0
30
1.60
2.50
8.0
25
1.80
5.00
18
20
1.90
10.00
38
15
1.95
0.01µF
VIN
3
5
1
1/2
OP292
1/2
OP292
7
VOUT
1.1kΩ 14.3kΩ
4
100µF 1.78kΩ 16.2kΩ
5kΩ
0.022µF
2200pF
3300pF
Figure 40. Four-Pole Bessel Low-Pass Filter Using Sallen-Key Topology
LOW COST, LINEARIZED THERMISTOR AMPLIFIER
An inexpensive thermometer amplifier circuit can be implemented
using low cost thermistors. One such implementation is shown
in Figure 41. The circuit measures temperature over the range
of 0°C to 70°C to an accuracy of ±0.3°C as the linearization
circuit works well within a narrow temperature range. However, it
can measure higher temperatures but at a slightly reduced accuracy.
To achieve the aforementioned accuracy, the nonlinearity of the
thermistor must be corrected. This is done by connecting the
thermistor in parallel with the 10 kΩ in the feedback loop of the
first stage amplifier. A constant operating current of 281 µA is
supplied by the resistor R1 with the 5 V reference from the
REF195 such that the self-heating error of the thermistor is
kept below 0.1°C.
To calibrate, a precision decade box can be used in place of the
thermistor. For 0°C trim, the decade box is set to 32.650 kΩ,
and P1 is adjusted until the output of the circuit reads 0 V. To
trim the circuit at the full-scale temperature of 70°C, the decade
box is then set to 1.752 kΩ, and P2 is adjusted until the circuit
reads −0.70 V.
+ C4
1µF
0.75
5kΩ
6
8
This linearization network creates an offset voltage that is corrected
by summing a compensating current with Potentiometer P1. The
temperature dependent signal is amplified by the second stage,
producing a transfer coefficient of −10 mV/°C at the output.
8kΩ
6V
1/4
OP492
2
In many cases, the thermistor is placed some distance from the
signal conditioning circuit. Under this condition, a 0.1 µF capacitor
placed across R2 will help to suppress noise pickup.
VOUT
R4
2.67kΩ
R5
1.335kΩ
(2.67k ÷ 2)
5V
5V
00310-040
50 Hz/60 Hz SINGLE-SUPPLY NOTCH FILTER
RT1
10kΩ NTC
15V
00310-039
NOTES
1. FOR 50Hz APPLICATION CHANGE R12 TO R4 TO 3.16kΩ
AND R5 TO 1.58kΩ (3.16kΩ ÷ 2)
1.0µF
R12
17.8kΩ
REF195
R12
17.8kΩ
1µF
Figure 39. Single-Supply 50 Hz/60 Hz Notch Filter
1/2
OP292
R3
10kΩ
R6
7.87kΩ
P2
200Ω
70°C TRIM
5V
The linear phase filter in Figure 40 is designed to roll off at a
voice-band cutoff frequency of 3.6 kHz. The four poles are
formed by two cascading stages of 2-pole Sallen-Key filters.
P1
10kΩ
0°C TRIM
1R
T
2R1
1/2
OP292
R5
806kΩ
VOUT
–10mV/°C
= ALPHA THERMISTOR 13A1002-C3.
= 0.1% IMPERIAL ASTRONICS M015.
NOTES
1. ALL RESISTORS ARE 1%, 25ppm/°C EXCEPT R5 = 1%, 100ppm/°C.
Figure 41. Low Cost Linearized Thermistor Amplifier
Rev. D | Page 15 of 20
00310-041
R4
41.2kΩ
FOUR-POLE BESSEL LOW-PASS FILTER
OP292/OP492
Data Sheet
SINGLE-SUPPLY ULTRASONIC
CLAMPING/LIMITING RECEIVER AMPLIFIER
PRECISION SINGLE-SUPPLY VOLTAGE
COMPARATOR
Figure 42 shows an ultrasonic receiver amplifier using the
nonlinear impedance of low cost diodes to effectively control
the gain for wide dynamic range. This circuit amplifies a 40 kHz
ultrasonic signal through a pair of low cost clamping amplifiers
before feeding a band-pass filter to extract a clean 40 kHz signal
for processing.
The OP292/OP492 have excellent overload recovery characteristics,
making them suitable for precision comparator applications.
Figure 43 shows the saturation recovery characteristics of the
OP492. The amplifier exhibits very little propagation delay. The
amplifier compares a signal to precisely
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