Zero Drift, Digitally Programmable
Instrumentation Amplifier
AD8231-EP
ENHANCED PRODUCT FEATURES
Supports defense and aerospace applications (AQEC
standard)
Military temperature range (−55°C to +125°C)
Controlled manufacturing baseline
One assembly/test site
One fabrication site
Enhanced product change notification
Qualification data available on request
–INA
+INA
NC
CS
13
A0
14
15
16
NC
A1
FUNCTIONAL BLOCK DIAGRAM
1
12
LOGIC
2
11
IN-AMP
3
10
4
9
+VS
–VS
OUTA
REF
AD8231-EP OP
09707-001
8
OUTB
7
–INB
6
+INB
5
AMP
SDN
Digitally/pin-programmable gain
G = 1, 2, 4, 8, 16, 32, 64, or 128
Specified from −55°C to +125°C
50 nV/°C maximum input offset drift
10 ppm/°C maximum gain drift
Excellent dc performance
80 dB minimum CMR, G = 1
15 μV maximum input offset voltage
500 pA maximum bias current
0.7 μV p-p noise (0.1 Hz to 10 Hz)
Good ac performance
2.7 MHz bandwidth, G = 1
1.1 V/μs slew rate
Rail-to-rail output
Shutdown/multiplex
Extra op amp
Single-supply range: 3 V to 6 V
Dual-supply range: ±1.5 V to ±3 V
A2
FEATURES
Figure 1.
Table 1. Instrumentation and Difference Amplifiers by
Category
High
Performance
AD8221
AD82201
AD8222
AD82241
1
Low
Cost
AD623 1
AD85531
High
Voltage
AD628
AD629
Mil
Grade
AD620
AD621
AD524
AD526
AD624
Low
Power
AD6271
Digital
Gain
AD82311
AD8250
AD8251
AD85551
AD85561
AD85571
Rail-to-rail output.
GENERAL DESCRIPTION
The AD8231-EP is a low drift, rail-to-rail, instrumentation
amplifier with software-programmable gains of 1, 2, 4, 8, 16, 32, 64,
or 128. The gains are programmed via digital logic or pin
strapping.
The AD8231-EP also includes an uncommitted op amp that can
be used for additional gain, differential signal driving, or filtering.
Like the in-amp, the op amp has an auto-zero architecture, railto-rail input, and rail-to-rail output.
The AD8231-EP is ideal for applications that require precision
performance over a wide temperature range, such as industrial
temperature sensing and data logging. Because the gain setting
resistors are internal, maximum gain drift is only 10 ppm/°C for
gains of 1 to 32. Because of the auto-zero input stage, maximum
input offset is 15 μV and maximum input offset drift is just
50 nV/°C. CMRR is 80 dB for G = 1, increasing to 110 dB at
higher gains.
The AD8231-EP includes a shutdown feature that reduces current
to a maximum of 1 μA. In shutdown, both amplifiers also have
a high output impedance, which allows easy multiplexing of
multiple amplifiers without additional switches.
The AD8231-EP is specified over the military temperature
range of −55°C to +125°C. It is available in a 4 mm × 4 mm 16lead LFCSP.
Additional application and technical information can be found
in the AD8231 data sheet.
Rev. 0
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 registered trademarks are the 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
©2011 Analog Devices, Inc. All rights reserved.
AD8231-EP
TABLE OF CONTENTS
Features .............................................................................................. 1 ESD Caution...................................................................................7 Enhanced Product Features ............................................................ 1 Pin Configuration and Function Descriptions..............................8 Functional Block Diagram .............................................................. 1 Typical Performance Characteristics ..............................................8 General Description ......................................................................... 1 Instrumentation Amplifier Performance Curves......................9 Revision History ............................................................................... 2 Operational Amplifier Performance Curves .......................... 15 Specifications..................................................................................... 3 Performance Curves Valid for Both Amplifiers ..................... 17 Absolute Maximum Ratings............................................................ 7 Outline Dimensions ....................................................................... 18 Thermal Resistance ...................................................................... 7 Ordering Guide .......................................................................... 18 Maximum Power Dissipation ..................................................... 7 REVISION HISTORY
5/11—Revision 0: Initial Version
Rev. 0 | Page 2 of 20
AD8231-EP
SPECIFICATIONS
VS = 5 V, VREF = 2.5 V, G = 1, RL = 10 kΩ, TA = 25°C, unless otherwise noted.
Table 2.
Parameter
INSTRUMENTATION AMPLIFIER
Offset Voltage
Input Offset, VOSI
Average Temperature Drift
Output Offset, VOSO
Average Temperature Drift
Input Currents
Input Bias Current
Test Conditions/Comments
Min
Typ
Max
Unit
4
0.01
15
0.05
15
0.05
30
0.5
μV
μV/°C
μV
μV/°C
250
500
5
100
0.5
pA
nA
pA
nA
0.05
0.8
%
%
10
20
30
ppm/°C
ppm/°C
ppm/°C
ppm
ppm
VOS RTI = VOSI + VOSO/G
TA = −55°C to +125°C
TA = −55°C to +125°C
TA = −55°C to +125°C
Input Offset Current
Gains
Gain Error
G=1
G = 2 to 128
Gain Drift
G = 1 to 32
G = 64
G = 128
Linearity
CMRR
G=1
G=2
G=4
G=8
G = 16
G = 32
G = 64
G = 128
Noise
Input Voltage Noise, eni
Output Voltage Noise, eno
Current Noise
Other Input Characteristics
Common-Mode Input Impedance
Power Supply Rejection Ratio
Input Operating Voltage Range
Reference Input
Input Impedance
Voltage Range
20
TA = −55°C to +125°C
1, 2, 4, 8, 16, 32, 64, or 128
TA = −55°C to +125°C
3
4
10
3
5
0.2 V to 4.8 V, 10 kΩ load
0.2 V to 4.8 V, 2 kΩ load
80
86
92
98
104
110
110
110
en = √(eni2 + (eno/G)2), VIN+, VIN− = 2.5 V
f = 1 kHz
f = 1 kHz, TA = −55°C
f = 1 kHz, TA = 125°C
f = 0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz, TA = −55°C
f = 1 kHz, TA = 125°C
f = 0.1 Hz to 10 Hz
f = 10 Hz
100
0.05
dB
dB
dB
dB
dB
dB
dB
dB
32
27
39
0.7
58
50
70
1.1
20
nV/√Hz
nV/√Hz
nV/√Hz
μV p-p
nV/√Hz
nV/√Hz
nV/√Hz
μV p-p
fA/√Hz
10||5
115
4.95
GΩ||pF
dB
V
+5.2
kΩ
V
28
−0.2
Rev. 0 | Page 3 of 20
AD8231-EP
Parameter
Dynamic Performance
Bandwidth
G=1
G=2
Gain Bandwidth Product
G = 4 to 128
Slew Rate
Output Characteristics
Output Voltage High
Output Voltage Low
Short-Circuit Current
Digital Interface
Input Voltage Low
Input Voltage High
Setup Time to CS High
Hold Time after CS High
OPERATIONAL AMPLIFIER
Input Characteristics
Offset Voltage, VOS
Temperature Drift
Input Bias Current
Test Conditions/Comments
RL = 100 kΩ to ground
RL = 10 kΩ to ground
RL = 100 kΩ to 5 V
RL = 10 kΩ to 5 V
TA = −55°C to +125°C
TA = −55°C to +125°C
TA = −55°C to +125°C
TA = −55°C to +125°C
Min
4.9
4.8
Typ
MHz
MHz
7
1.1
MHz
V/μs
4.94
4.88
60
80
70
V
V
mV
mV
mA
1.0
V
V
ns
ns
15
0.06
500
5
100
0.5
4.95
120
120
110
20
0.4
μV
μV/°C
pA
nA
pA
nA
V
V/mV
dB
dB
nV/√Hz
μV p-p
1
0.5
MHz
V/μs
4.96
4.92
60
80
70
V
V
mV
mV
mA
5
0.01
250
Input Offset Current
20
TA = −55°C to +125°C
Output Voltage Low
0.05
100
100
100
f = 0.1 Hz to 10 Hz
RL = 100 kΩ to ground
RL = 10 kΩ to ground
RL = 100 kΩ to 5 V
RL = 10 kΩ to 5 V
Short-Circuit Current
BOTH AMPLIFIERS
Power Supply
Quiescent Current
Quiescent Current (Shutdown)
4.9
4.8
4
0.01
Rev. 0 | Page 4 of 20
100
200
4.0
50
20
TA = −55°C to +125°C
Unit
2.7
2.5
TA = −55°C to +125°C
Input Voltage Range
Open-Loop Gain
Common-Mode Rejection Ratio
Power Supply Rejection Ratio
Voltage Noise Density
Voltage Noise
Dynamic Performance
Gain Bandwidth Product
Slew Rate
Output Characteristics
Output Voltage High
Max
100
200
5
1
mA
μA
AD8231-EP
VS = 3.0 V, VREF = 1.5 V, TA = 25°C, G = 1, RL = 10 kΩ, unless otherwise noted.
Table 3.
Parameter
INSTRUMENTATION AMPLIFIER
Offset Voltage
Input Offset, VOSI
Average Temperature Drift
Output Offset, VOSO
Average Temperature Drift
Input Currents
Input Bias Current
Conditions
Min
Typ
Max
Unit
4
0.01
15
0.05
15
0.05
30
0.5
μV
μV/°C
μV
μV/°C
250
500
5
100
0.5
pA
nA
pA
nA
0.05
0.8
%
%
10
20
30
ppm/°C
ppm/°C
ppm/°C
VOS RTI = VOSI + VOSO/G
TA = −55°C to +125°C
Input Offset Current
Gains
Gain Error
G=1
G = 2 to 128
Gain Drift
G = 1 to 32
G = 64
G = 128
CMRR
G=1
G=2
G=4
G=8
G = 16
G = 32
G = 64
G = 128
Noise
Input Voltage Noise, eni
Output Voltage Noise, eno
Current Noise
Other Input Characteristics
Common-Mode Input Impedance
Power Supply Rejection Ratio
Input Operating Voltage Range
Reference Input
Input Impedance
Voltage Range
20
TA = −55°C to +125°C
1, 2, 4, 8, 16, 32, 64, or 128
TA = −55°C to +125°C
3
4
10
80
86
92
98
104
110
110
110
en = √(eni2 + (eno/G)2)
VIN+, VIN− = 2.5 V, TA = 25°C
f = 1 kHz
f = 1 kHz, TA = −55°C
f = 1 kHz, TA = 125°C
f = 0.1 Hz to 10 Hz
f = 1 kHz
f = 1 kHz, TA = −55°C
f = 1 kHz, TA = 125°C
f = 0.1 Hz to 10 Hz
f = 10 Hz
100
0.05
dB
dB
dB
dB
dB
dB
dB
dB
40
35
48
0.8
72
62
83
1.4
20
nV/√Hz
nV/√Hz
nV/√Hz
μV p-p
nV/√Hz
nV/√Hz
nV/√Hz
μV p-p
fA/√Hz
10||5
115
2.95
GΩ||pF
dB
V
+3.2
kΩ||pF
V
28
−0.2
Rev. 0 | Page 5 of 20
AD8231-EP
Parameter
Dynamic Performance
Bandwidth
G=1
G=2
Gain Bandwidth Product
G = 4 to 128
Slew Rate
Output Characteristics
Output Voltage High
Output Voltage Low
Short-Circuit Current
Digital Interface
Input Voltage Low
Input Voltage High
Setup Time to CS High
Hold Time after CS High
OPERATIONAL AMPLIFIERS
Input Characteristics
Offset Voltage, VOS
Temperature Drift
Input Bias Current
Conditions
RL = 100 kΩ to ground
RL = 10 kΩ to ground
RL = 100 kΩ to 3 V
RL = 10 kΩ to 3 V
TA = −55°C to +125°C
TA = −55°C to +125°C
TA = −55°C to +125°C
TA = −55°C to +125°C
Min
2.9
2.8
Typ
MHz
MHz
7
1.1
MHz
V/μs
2.94
2.88
60
80
40
V
V
mV
mV
mA
V
V
ns
ns
15
0.06
500
5
100
0.5
2.95
120
120
110
27
0.6
μV
μV/°C
pA
nA
pA
nA
V
V/mV
dB
dB
nV/√Hz
μV p-p
1
0.5
MHz
V/μs
2.96
2.82
60
80
40
V
V
mV
mV
mA
TA = −55°C to +125°C
20
TA = −55°C to +125°C
Output Voltage Low
0.05
100
100
100
f = 0.1 Hz to 10 Hz
RL = 100 kΩ to ground
RL = 10 kΩ to ground
RL = 100 kΩ to 3 V
RL = 10 kΩ to 3 V
Short-Circuit Current
BOTH AMPLIFIERS
Power Supply
Quiescent Current
Quiescent Current (Shutdown)
2.9
2.8
3.5
0.01
Rev. 0 | Page 6 of 20
100
200
0.7
5
0.01
250
TA = −55°C to +125°C
Unit
2.7
2.5
2.3
60
20
Input Offset Current
Input Voltage Range
Open-Loop Gain
Common-Mode Rejection Ratio
Power Supply Rejection Ratio
Voltage Noise Density
Voltage Noise
Dynamic Performance
Gain Bandwidth Product
Slew Rate
Output Characteristics
Output Voltage High
Max
100
200
4.5
1
mA
μA
AD8231-EP
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 4.
Parameter
Supply Voltage
Output Short-Circuit Current
Input Voltage (Common-Mode)
Differential Input Voltage
Storage Temperature Range
Operational Temperature Range
Package Glass Transition Temperature
ESD (Human Body Model)
ESD (Charged Device Model)
ESD (Machine Model)
Rating
6V
Indefinite1
−VS − 0.3 V to +VS + 0.3 V
−VS − 0.3 V to +VS + 0.3 V
–65°C to +150°C
–55°C to +125°C
130°C
1.5 kV
1.5 kV
0.2 kV
1
For junction temperatures between 105°C and 130°C, short-circuit operation
beyond 1000 hours can impact part reliability.
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.
Table 5.
Thermal Pad
Soldered to Board
Not Soldered to Board
θJA
54
96
Unit
°C/W
°C/W
The θJA values in Table 5 assume a 4-layer JEDEC standard
board. If the thermal pad is soldered to the board, it is
also assumed it is connected to a plane. θJC at the exposed pad
is 6.3°C/W.
MAXIMUM POWER DISSIPATION
The maximum safe power dissipation for the AD8231-EP is
limited by the associated rise in junction temperature (TJ) on
the die. At approximately 130°C, which is the glass transition
temperature, the plastic changes its properties. Even
temporarily exceeding this temperature limit may change the
stresses that the package exerts on the die, permanently shifting
the parametric performance of the amplifiers. Exceeding a
temperature of 130°C for an extended period can result in a loss
of functionality.
ESD CAUTION
Rev. 0 | Page 7 of 20
AD8231-EP
12 +VS
11 –VS
10 OUTA (IN-AMP OUT)
9 REF
14 A0
NOTES
1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN.
2. THE EXPOSED PAD CAN BE CONNECTED TO THE
NEGATIVE SUPPLY (–VS) OR LEFT FLOATING.
09707-002
OUTB (OP AMP OUT) 8
–INB 7
TOP VIEW
(Not to Scale)
SDN 5
NC 4
AD8231-EP
+INB 6
+INA (IN-AMP +IN) 3
13 CS
PIN 1
INDICATOR
NC 1
–INA (IN-AMP –IN) 2
15 A1
16 A2
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Figure 2. Pin Configuration
Table 6. Pin Function Descriptions
Pin Number
1
2
3
4
5
6
7
8
9
Mnemonic
NC
−INA (IN-AMP −IN)
+INA (IN-AMP +IN)
NC
SDN
+INB
−INB
OUTB (OP AMP OUT)
REF
10
11
12
13
14
15
16
OUTA (IN-AMP OUT)
−VS
+VS
CS
A0
A1
A2
EPAD
Description
No Connect. Do not connect to this pin.
Instrumentation Amplifier Negative Input.
Instrumentation Amplifier Positive Input.
No Connect. Do not connect to this pin.
Shutdown.
Operational Amplifier Positive Input.
Operational Amplifier Negative Input.
Operational Amplifier Output.
Instrumentation Amplifier Reference Pin. It should be driven with a low impedance. Output is
referred to this pin.
Instrumentation Amplifier Output.
Negative Power Supply. Connect to ground in single-supply applications.
Positive Power Supply.
Chip Select. Enables digital logic interface.
Gain Setting Bit (LSB).
Gain Setting Bit.
Gain Setting Bit (MSB).
Exposed Pad. Can be connected to the negative supply (−VS) or left floating.
Rev. 0 | Page 8 of 20
AD8231-EP
TYPICAL PERFORMANCE CHARACTERISTICS
INSTRUMENTATION AMPLIFIER PERFORMANCE CURVES
1000
1400
N: 5956
MEAN: 0.977167
SD: 11.8177
N: 5956
MEAN: –48.0779
1200 SD: 21.0433
800
1000
600
HITS
HITS
800
400
600
400
200
–60
–40
–20
0
20
40
60
80
100
CMRR (µV/V)
0
–500 –400 –300 –200 –100
Figure 3. Instrumentation Amplifier CMR Distribution, G = 1
200
300
400
500
1400
N: 5956
MEAN: 2.06788
700 SD: 1.07546
1200
INPUT OFFSET (nV)
600
500
HITS
100
Figure 6. Instrumentation Amplifier Gain Distribution, G = 1
800
400
300
200
1000
800
600
400
200
100
–10
–5
0
5
10
15
VOSI (µV)
0
–55 –45 –35 –25 –15 –5
09707-101
0
–15
0
GAIN ERROR (µV/V)
5
15
25
35
45
55
65
75
TEMPERATURE (°C)
09707-207
–80
09707-100
0
–100
09707-103
200
Figure 7. Instrumentation Amplifier Input Offset Voltage Drift,
−55°C to +125°C
Figure 4. Instrumentation Amplifier Input Offset Voltage Distribution
20
800
N: 5956
MEAN: 10.3901
700 SD: 3.9553
15
OUTPUT OFFSET (µV)
600
HITS
500
400
300
10
5
0
200
–20
–10
0
VOSO (µV)
10
20
30
–10
–55 –45 –35 –25 –15 –5
09707-102
0
–30
Figure 5. Instrumentation Amplifier Output Offset Voltage Distribution
5
15
25
TEMPERATURE (°C)
35
45
55
65
75
09707-208
–5
100
Figure 8. Instrumentation Amplifier Output Offset Drift, −55°C to +125°C
Rev. 0 | Page 9 of 20
AD8231-EP
6
VREF = MIDSUPPLY
VCM = MIDSUPPLY
0V, 4.96V
1000
500
3V
0
5
4
5V SINGLE SUPPLY
0V, 2.96V
2
3V SINGLE SUPPLY
1
20
35
50
65
80
95
110 125
TEMPERATURE (°C)
0
09707-209
5
Figure 9. Instrumentation Amplifier Bias Current vs. Temperature
0
2
3
4
5
6
Figure 12. Instrumentation Amplifier Input Common-Mode Range vs.
Output Voltage, VREF = 0 V
6
INPUT COMMON-MODE VOLTAGE (V)
1.5
1.0
0.5
0
–0.5
–1.0
+VS = +2.5V
–VS = –2.5V
VREF = 0V
–2.0
–2.5
–2.0
–1.5
–1.0
–0.5
0
0.5
1.0
1.5
2.0
2.5
VCM (V)
4 0.02V, 4.22V
5V SINGLE SUPPLY
1.5V, 2.96V
3
2 0.02V, 2.22V
4.98V, 3.22V
2.98V, 2.22V
4.98V, 1.78V
3V SINGLE SUPPLY
1
2.98V, 0.78V
0.02V, 0.78V
1.5V, 0.04V
0
0
09707-006
–1.5
1.5V, 4.96V
5
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
OUTPUT VOLTAGE (V)
09707-004
BIAS CURRENT (nA)
1
OUTPUT VOLTAGE (V)
2.0
Figure 13. Instrumentation Amplifier Input Common-Mode Range vs.
Output Voltage, VREF = 1.5 V
Figure 10. Instrumentation Amplifier Bias Current vs.
Common-Mode Voltage, 5 V
6
1.0
INPUT COMMON-MODE VOLTAGE (V)
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
+VS = +1.5V
–VS = –1.5V
VREF = 0V
–0.8
–1.0
–1.5
–1.2
–0.9
–0.6
–0.3
0
0.3
0.6
0.9
1.2
VCM (V)
Figure 11. Instrumentation Amplifier Bias Current vs.
Common-Mode Voltage, 3 V
1.5
2.5V, 4.96V
5
5V SINGLE SUPPLY
4
4.98V, 3.72V
0.02V, 3.72V
3
2.5V, 2.96V
2.98V, 2.72V
2
0.02V, 1.72V
3V SINGLE
SUPPLY
0.02V, 1.28V
2.5V, 0.04V
4.98V,1.28V
1
2.98V, 0.28V
0
0
09707-007
BIAS CURRENT (nA)
2.92V, 1.5V
0V, 0.04V
5V
–500
–55 –40 –25 –10
4.92V, 2.5V
3
0.5
1.0
1.5
2.0
2.5
3.0
3.5
OUTPUT VOLTAGE (V)
4.0
4.5
5.0
09707-005
BIAS CURRENT (pA)
1500
09707-003
INPUT COMMON-MODE VOLTAGE (V)
2000
Figure 14. Instrumentation Amplifier Input Common-Mode Range vs.
Output Voltage, VREF = 2.5 V
Rev. 0 | Page 10 of 20
AD8231-EP
50
40
15
G = 64
G = 32
30
5
G=8
CMRR (µV/V)
G=4
10
G=2
G=1
0
G=1
10
G = 16
20
–10
G=8
G = 128
0
–5
–10
–15
–20
–20
–30
–25
1k
10k
100k
1M
10M
FREQUENCY (Hz)
–30
–55 –40 –25 –10
09707-009
–40
100
5
20
35
50
65
80
95
Figure 18. Instrumentation Amplifier CMRR vs. Temperature
Figure 15. Instrumentation Amplifier Gain vs. Frequency
140
1000
800
G=1
120
G=8
600
POSITIVE PSRR (dB)
GAIN ERROR (µV/V)
900
200
0
G=1
–200
–400
110 125
TEMPERATURE (°C)
09707-218
GAIN (dB)
20
G = 128
G = 128
100
G = 128
80
60
40
–600
20
5
20
35
50
65
80
95
110 125
TEMPERATURE (°C)
0
09707-216
–1000
–55 –40 –25 –10
1
10
100
Figure 16. Instrumentation Amplifier Gain Drift vs. Temperature
10k
100k
Figure 19. Instrumentation Amplifier Positive PSRR vs. Frequency
140
140
G = 128
G=1
120
120
NEGATIVE PSRR (dB)
G=8
G=8
100
G=1
80
100
80
G = 128
60
40
60
40
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 17. Instrumentation Amplifier CMRR vs. Frequency
0
1
10
100
1k
100k
100k
FREQUENCY (Hz)
Figure 20. Instrumentation Amplifier Negative PSRR vs. Frequency
Rev. 0 | Page 11 of 20
09707-147
20
09707-010
CMRR (dB)
1k
FREQUENCY (Hz)
09707-146
–800
AD8231-EP
G = +128, 0.4µV/DIV
09707-012
G = +1, 1µV/DIV
1s/DIV
10
1
0.1
0.01
1
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 21. Instrumentation Amplifier 0.1 Hz to 10 Hz Noise
100
09707-107
CURRENT NOISE (pA/ Hz)
100
Figure 24. Instrumentation Amplifier Current Noise Spectral Density
G = +1
G = +8
G = +128
90
80
NOISE (nV/ Hz)
70
60
50
40
30
10
1
10
100
1k
FREQUENCY (Hz)
Figure 22. Instrumentation Amplifier Voltage Noise Spectral Density vs.
Frequency, 5 V, 1 Hz to 1000 Hz
1000
Figure 25. Instrumentation Amplifier Small Signal Pulse Response, G = 1,
RL = 2 kΩ, CL = 500 pF
G = +1
G = +8
G = +128
900
5µs/DIV
09707-011
20mV/DIV
0
09707-013
20
300pF
NO
LOAD
500pF
800pF
800
NOISE (nV/ Hz)
700
600
500
400
300
100
1
10
100
1k
FREQUENCY (Hz)
10k
100k
4µs/DIV
09707-008
20mV/DIV
0
09707-014
200
Figure 23. Instrumentation Amplifier Voltage Noise Spectral Density vs.
Frequency, 5 V, 1 Hz to 1 MHz
Figure 26. Instrumentation Amplifier Small Signal Pulse Response for Various
Capacitive Loads, G = 1
Rev. 0 | Page 12 of 20
AD8231-EP
G = +8
G = +32
G = +128
2V/DIV
10µs/DIV
0.001%/DIV
Figure 27. Instrumentation Amplifier Small Signal Pulse Response, G = 4, 16,
and 128, RL = 2 kΩ, CL = 500 pF
100µs/DIV
09707-018
20mV/DIV
09707-015
17.6µs TO 0.01%
21.4µs TO 0.001%
Figure 30. Instrumentation Amplifier Large Signal Pulse Response,
G = 128, VS = 5 V
25
20
SETTLING TIME (µs)
2V/DIV
3.95µs TO 0.01%
4µs TO 0.001%
0.001%
15
0.01%
10
0
1
10
100
1k
09707-019
10µs/DIV
1k
09707-020
0.001%/DIV
09707-016
5
GAIN (V/V)
Figure 28. Instrumentation Amplifier Large Signal Pulse Response,
G = 1, VS = 5 V
Figure 31. Instrumentation Amplifier Settling Time vs.
Gain for a 4 V p-p Step, VS = 5 V
25
0.001%
20
SETTLING TIME (µs)
2V/DIV
3.75µs TO 0.01%
3.8µs TO 0.001%
15
0.01%
10
0.001%/DIV
10µs/DIV
09707-017
5
0
1
10
100
GAIN (V/V)
Figure 29. Instrumentation Amplifier Large Signal Pulse Response,
G = 8, VS = 5 V
Figure 32. Instrumentation Amplifier Settling Time vs.
Gain for a 2 V p-p Step, VS = 3 V
Rev. 0 | Page 13 of 20
AD8231-EP
–0.2
–0.4
–0.6
–0.8
–1.0
+1.0
+0.8
+0.6
+0.4
+0.2
–VS
0.1
+25°C
–55°C
1
10
100
OUTPUT CURRENT (mA)
–0.2
–0.4
–0.6
–0.8
–1.0
+1.0
+0.8
+0.6
+0.4
+0.2
–VS
0.1
+25°C
–55°C
1
10
100
OUTPUT CURRENT (mA)
Figure 34. Instrumentation Amplifier Output Voltage Swing vs.
Output Current, VS = 5 V
Figure 33. Instrumentation Amplifier Output Voltage Swing vs.
Output Current, VS = 3 V
Rev. 0 | Page 14 of 20
09707-234
OUTPUT VOLTAGE SWING REFERRED TO
SUPPLY VOLTAGES (V)
+VS
09707-233
OUTPUT VOLTAGE SWING REFERRED TO
SUPPLY VOLTAGES (V)
+VS
AD8231-EP
–100
60
–110
40
–120
76° PHASE
MARGIN
20
–130
0
–140
800pF
1nF
1.5nF
20mV/DIV
1k
10k
100k
1M
–150
10M
FREQUENCY (Hz)
Figure 38. Operational Amplifier Small Signal Response for
Various Capacitive Loads, VS = 3 V
60
–110
40
–120
72° PHASE
MARGIN
20
–130
0
–140
RL = 10kΩ
CL = 200pF
–20
10
100
1k
10k
100k
1M
–150
10M
FREQUENCY (Hz)
Figure 36. Operational Amplifier Open-Loop Gain and Phase vs.
Frequency, VS = 3 V
800pF
1nF
OUTPUT VOLTAGE (0.5V/DIV)
–100
OPEN-LOOP PHASE SHIFT (Degrees)
80
1nF║2kΩ
1.5nF║2kΩ
TIME (5µs/DIV)
Figure 39. Operational Amplifier Large Signal Transient Response, VS = 5 V
NO
LOAD
2nF
OUTPUT VOLTAGE (0.5V/DIV)
NO
LOAD
1.5nF
20mV/DIV
NO
LOAD
09707-022
–90
5µs/DIV
1nF║2kΩ
1.5nF║2kΩ
09707-023
OPEN-LOOP GAIN (dB)
Figure 35. Operational Amplifier Open-Loop Gain and Phase vs.
Frequency, VS = 5 V
100
5µs/DIV
TIME (5µs/DIV)
Figure 37. Operational Amplifier Small Signal Response for
Various Capacitive Loads, VS = 5 V
09707-026
RL = 10kΩ
CL = 200pF
–20
10
100
300pF
09707-024
80
NO
LOAD
09707-025
–90
OPEN-LOOP PHASE SHIFT (Degrees)
100
09707-021
OPEN-LOOP GAIN (dB)
OPERATIONAL AMPLIFIER PERFORMANCE CURVES
Figure 40. Operational Amplifier Large Signal Transient Response, VS = 3 V
Rev. 0 | Page 15 of 20
AD8231-EP
+VS
800
700
600
500
400
300
200
0
10
100
1k
10k
100k
FREQUENCY (Hz)
BIAS CURRENT (nA)
2.5
2.0
1.5
1.0
0.5
+0.6
+0.4
+0.2
5
20
35
50
65
80
95
110 125
TEMPERATURE (°C)
10
100
–0.2
–0.4
–0.6
–0.8
–1.0
+1.0
+0.8
+0.6
+0.4
+0.2
+25°C
–55°C
1
10
100
Figure 45. Operational Amplifier Output Voltage Swing vs.
Output Current, VS = 5 V
400
140
300
120
+PSRR
200
100
PSRR (dB)
100
VS = ±2.5V
–100
VS = ±1.5V
80
–PSRR
60
40
–200
20
–2
–1
0
1
2
3
VCM (V)
09707-109
–300
–400
–3
1
OUTPUT CURRENT (mA)
Figure 42. Operational Amplifier Bias Current vs. Temperature
0
+25°C
–55°C
–VS
0.1
09707-242
0
BIAS CURRENT (pA)
+0.8
+VS
VS = ±2.5V
VS = ±1.5V
–0.5
–55 –40 –25 –10
–1.0
+1.0
Figure 44. Operational Amplifier Output Voltage Swing vs.
Output Current, VS = 3 V
OUTPUT VOLTAGE SWING REFERRED TO
SUPPLY VOLTAGES (V)
3.0
–0.8
OUTPUT CURRENT (mA)
Figure 41. Operational Amplifier Voltage Spectral Noise Density vs. Frequency
3.5
–0.6
09707-245
1
–0.4
–VS
0.1
09707-141
100
–0.2
0
1
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 46. Operational Amplifier Power Supply Rejection Ratio
Figure 43. Operational Amplifier Bias Current vs. Common Mode
Rev. 0 | Page 16 of 20
09707-148
SPECTRAL NOISE DENSITY (nV/ Hz)
900
09707-244
OUTPUT VOLTAGE SWING REFERRED TO
SUPPLY VOLTAGES (V)
1000
AD8231-EP
160
6
140
CHANNEL SEPARATION (dB)
7
5
4
+25°C
3
–55°C
2
1
G = 128
120
G=1
100
80
60
40
3.1
3.5
3.9
4.3
4.7
5.1
SUPPLY VOLTAGE (V)
5.5
5.9
0
10
SOURCE CHANNEL: OP AMP AT G = 1
100
1k
10k
FREQUENCY (Hz)
Figure 48. Channel Separation vs. Frequency
Figure 47. Supply Current vs. Supply Voltage
Rev. 0 | Page 17 of 20
100k
09707-149
0
2.7
G=8
20
09707-247
SUPPLY CURRENT (mA)
PERFORMANCE CURVES VALID FOR BOTH AMPLIFIERS
AD8231-EP
OUTLINE DIMENSIONS
4.00
BSC SQ
3.75
BSC SQ
0.75
0.60
0.50
0.80 MAX
0.65 TYP
12° MAX
1.00
0.85
0.80
0.65 BSC
TOP
VIEW
SEATING
PLANE
16
13
12
9
PIN 1
INDICATOR
1
2.25
2.10 SQ
1.95
8
5
4
0.25 MIN
1.95 BSC
0.05 MAX
0.02 NOM
0.35
0.30
0.25
(BOTTOM VIEW)
0.20 REF
COPLANARITY
0.08
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
COMPLIANT TO JEDEC STANDARDS MO-220-VGGC
072808-A
PIN 1
INDICATOR
0.60 MAX
0.60 MAX
Figure 49. 16-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
4 mm × 4 mm Body, Very Thin Quad
(CP-16-4)
Dimensions shown in millimeters
ORDERING GUIDE
Model 1
AD8231TCPZ-EP-R7
1
Temperature Range
−55°C to +125°C
Package Description
16-Lead LFCSP_VQ, 7” Tape and Reel
Z = RoHS Compliant Part.
Rev. 0 | Page 18 of 20
Package Option
CP-16-4
AD8231-EP
NOTES
Rev. 0 | Page 19 of 20
AD8231-EP
NOTES
©2011 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D09707-0-5/11(0)
Rev. 0 | Page 20 of 20