3 nV/√Hz, Low Power
Instrumentation Amplifier
AD8421-EP
Enhanced Product
PIN CONNECTION DIAGRAM
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
GENERAL DESCRIPTION
The AD8421-EP is a low cost, low power, extremely low noise,
ultralow bias current, high speed instrumentation amplifier that
is ideally suited for a broad spectrum of signal conditioning and
data acquisition applications. This product features extremely
high CMRR, allowing it to extract low level signals in the presence
of high frequency common-mode noise over a wide
temperature range.
The 10 MHz bandwidth, 35 V/μs slew rate, and 0.6 μs settling
time to 0.001% (G = 10) allow the AD8421-EP to amplify high
speed signals and excel in applications that require high channel
count, multiplexed systems. Even at higher gains, the current
feedback architecture maintains high performance; for example,
at G = 100, the bandwidth is 2 MHz and the settling time is
0.8 μs. The AD8421-EP has excellent distortion performance,
making it suitable for use in demanding applications such as
vibration analysis.
Rev. 0
1
8
+VS
RG
2
7
VOUT
RG
3
6
REF
+IN
4
5
–VS
Figure 1.
10µ
G = 100
BEST AVAILABLE
7mA LOW NOISE IN-AMP
1µ
100n
10n
BEST AVAILABLE
1mA LOW POWER IN-AMP
AD8421
RS NOISE ONLY
1n
100
1k
10k
100k
SOURCE RESISTANCE, RS (Ω)
1M
11139-078
ENHANCED PRODUCT FEATURES
AD8421-EP
–IN
TOP VIEW
(Not to Scale)
TOTAL NOISE DENSITY AT 1kHz (V/√Hz)
Specified from −55°C to 125°C
0.9 μV/°C maximum input offset voltage drift
5 ppm/°C maximum gain drift (G = 1)
Low power
2.3 mA maximum supply current
Low noise
3.2 nV/√Hz maximum input voltage noise at 1 kHz
200 fA/√Hz current noise at 1 kHz
Excellent ac specifications
2 MHz bandwidth (G = 100)
0.6 μs settling time to 0.001% (G = 10)
80 dB minimum CMRR at 20 kHz (G = 1)
High precision dc performance
84 dB CMRR minimum (G = 1)
2 nA maximum input bias current
Inputs protected to 40 V from opposite supply
Gain set with a single resistor (G = 1 to 10,000)
11139-001
FEATURES
Figure 2. Noise Density vs. Source Resistance
The AD8421-EP delivers 3 nV/√Hz input voltage noise and
200 fA/√Hz current noise with only 2 mA quiescent current,
making it an ideal choice for measuring low level signals. For
applications with high source impedance, the AD8421-EP employs
innovative process technology and design techniques to provide
noise performance that is limited only by the sensor.
The AD8421-EP uses unique protection methods to ensure robust
inputs while still maintaining very low noise. This protection
allows input voltages up to 40 V from the opposite supply rail
without damage to the part.
A single resistor sets the gain from 1 to 10,000. The reference
pin can be used to apply a precise offset to the output voltage.
The AD8421-EP is specified over the military temperature range of
−55°C to +125°C. It is available in an 8-lead MSOP package.
Additional application and technical information can be found
in the AD8421 data sheet.
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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.
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One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
©2013 Analog Devices, Inc. All rights reserved.
Technical Support
www.analog.com
AD8421-EP
Enhanced Product
TABLE OF CONTENTS
Features .............................................................................................. 1
ESD Caution...................................................................................6
General Description ......................................................................... 1
Pin Configuration and Function Descriptions..............................7
Revision History ............................................................................... 2
Typical Performance Characteristics ..............................................8
Specifications..................................................................................... 3
Outline Dimensions ....................................................................... 18
Absolute Maximum Ratings ............................................................ 6
Ordering Guide .......................................................................... 18
Thermal Resistance ...................................................................... 6
REVISION HISTORY
5/13—Revision 0: Initial Version
Rev. 0 | Page 2 of 20
Enhanced Product
AD8421-EP
SPECIFICATIONS
VS = ±15 V, VREF = 0 V, TA = 25°C, G = 1, RL = 2 kΩ, unless otherwise noted.
Table 1.
Parameter
COMMON-MODE REJECTION RATIO (CMRR)
CMRR DC to 60 Hz with 1 kΩ Source Imbalance
G=1
G = 10
G = 100
G = 1000
Over Temperature, G = 1
CMRR at 20 kHz
G=1
G = 10
G = 100
G = 1000
NOISE
Voltage Noise, 1 kHz 1
Input Voltage Noise, eni
Output Voltage Noise, eno
Peak to Peak, RTI
G=1
G = 10
G = 100 to 1000
Current Noise
Spectral Density
Peak to Peak, RTI
VOLTAGE OFFSET 2
Input Offset Voltage, VOSI
Over Temperature
Average TC
Output Offset Voltage, VOSO
Over Temperature
Average TC
Offset RTI vs. Supply (PSR)
G=1
G = 10
G = 100
G = 1000
INPUT CURRENT
Input Bias Current
Over Temperature
Average TC
Input Offset Current
Over Temperature
Average TC
Test Conditions/ Comments
Min
Typ
Max
Unit
VCM = −10 V to +10 V
TA = −55°C to +125°C
VCM = −10 V to +10 V
84
104
124
134
80
dB
dB
dB
dB
dB
80
90
100
100
dB
dB
dB
dB
VIN+, VIN− = 0 V
3
3.2
60
nV/√Hz
nV/√Hz
f = 0.1 Hz to 10 Hz
f = 1 kHz
f = 0.1 Hz to 10 Hz
2
0.5
0.07
µV p-p
µV p-p
µV p-p
200
18
fA/√Hz
pA p-p
VS = ±5 V to ±15 V
TA = −55°C to +125°C
70
160
0.9
600
1.5
9
TA = −55°C to +125°C
µV
µV
µV/°C
µV
mV
µV/°C
VS = ±2.5 V to ±18 V
90
110
124
130
120
120
130
140
1
TA = −55°C to +125°C
50
0.5
TA = −55°C to +125°C
1
Rev. 0 | Page 3 of 20
dB
dB
dB
dB
2
8
2
3
nA
nA
pA/°C
nA
nA
pA/°C
AD8421-EP
Parameter
DYNAMIC RESPONSE
Small Signal Bandwidth
G=1
G = 10
G = 100
G = 1000
Settling Time 0.01%
G=1
G = 10
G = 100
G = 1000
Settling Time 0.001%
G=1
G = 10
G = 100
G = 1000
Slew Rate
G = 1 to 100
GAIN 3
Gain Range
Gain Error
G=1
G = 10 to 1000
Gain Nonlinearity
G=1
G = 10 to 1000
Gain vs. Temperature3
G=1
G>1
INPUT
Input Impedance
Differential
Common Mode
Input Operating Voltage Range 4
Over Temperature
OUTPUT
Output Swing
Over Temperature
Short-Circuit Current
REFERENCE INPUT
RIN
IIN
Voltage Range
Reference Gain to Output
Enhanced Product
Test Conditions/ Comments
Min
Typ
Max
Unit
−3 dB
10
10
2
0.2
MHz
MHz
MHz
MHz
0.7
0.4
0.6
5
µs
µs
µs
µs
1
0.6
0.8
6
µs
µs
µs
µs
35
V/µs
10 V step
10 V step
G = 1 + (9.9 kΩ/RG)
1
10,000
V/V
0.05
0.3
%
%
1
3
50
10
ppm
ppm
ppm
ppm
5
−80
ppm/°C
ppm/°C
−VS + 2.3
−VS + 2.5
−VS + 2.1
+VS − 1.8
+VS − 2.0
+VS − 1.8
GΩ||pF
GΩ||pF
V
V
V
−VS + 1.2
−VS + 1.4
+VS − 1.7
+VS − 1.9
VOUT = ±10 V
VOUT = −10 V to +10 V
RL ≥ 2 kΩ
RL = 600 Ω
RL ≥ 600 Ω
VOUT = −5 V to +5 V
1
30
5
30||3
30||3
VS = ±2.5 V to ±18 V
TA = −55°C
TA = +125°C
RL = 2 kΩ
VS = ±2.5 V to ±18 V
TA = −55°C to +125°C
65
20
20
VIN+, VIN− = 0 V
−VS
1±
0.0001
Rev. 0 | Page 4 of 20
24
+VS
V
V
mA
kΩ
µA
V
V/V
Enhanced Product
Parameter
POWER SUPPLY
Operating Range
Quiescent Current
Over Temperature
TEMPERATURE RANGE
For Specified Performance
AD8421-EP
Test Conditions/ Comments
Min
Dual supply
Single supply
±2.5
5
Typ
2
TA = −55°C to +125°C
−55
Max
Unit
±18
36
2.3
2.8
V
V
mA
mA
+125
°C
Total voltage noise = √(eni2 + (eno/G)2 + eRG2). See the AD8421 data sheet for more information.
Total RTI VOS = (VOSI) + (VOSO/G).
3
These specifications do not include the tolerance of the external gain setting resistor, RG. For G > 1, add RG errors to the specifications given in this table.
4
Input voltage range of the AD8421-EP input stage only. The input range can depend on the common-mode voltage, differential voltage, gain, and reference voltage.
See the Typical Performance Characteristics section for more information.
1
2
Rev. 0 | Page 5 of 20
AD8421-EP
Enhanced Product
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 2.
Parameter
Supply Voltage
Output Short-Circuit Current Duration
Maximum Voltage at −IN or +IN1
Minimum Voltage at −IN or +IN
Maximum Voltage at REF2
Minimum Voltage at REF
Storage Temperature Range
Operating Temperature Range
Maximum Junction Temperature
ESD
Human Body Model
Charged Device Model
Machine Model
θJA is specified for a device in free air using a 4-layer JEDEC
printed circuit board (PCB).
Rating
±18 V
Indefinite
−VS + 40 V
+VS − 40 V
+VS + 0.3 V
−VS − 0.3 V
−65°C to +150°C
−55°C to +125°C
150°C
Table 3.
Package
8-Lead MSOP
ESD CAUTION
2 kV
1.25 kV
0.2 kV
For voltages beyond these limits, use input protection resistors. See the
AD8421 data sheet for more information.
2
There are ESD protection diodes from the reference input to each supply, so
REF cannot be driven beyond the supplies in the same way that +IN and −IN
can. See the AD8421 data sheet for more information.
1
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.
Rev. 0 | Page 6 of 20
θJA
138.6
Unit
°C/W
Enhanced Product
AD8421-EP
–IN
1
RG
AD8421-EP
8
+VS
2
7
VOUT
RG
3
6
REF
+IN
4
5
–VS
TOP VIEW
(Not to Scale)
11139-002
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
1
2, 3
4
5
6
7
8
Mnemonic
−IN
RG
+IN
−VS
REF
VOUT
+VS
Description
Negative Input Terminal.
Gain Setting Terminals. Place resistor across the RG pins to set the gain. G = 1 + (9.9 kΩ/RG).
Positive Input Terminal.
Negative Power Supply Terminal.
Reference Voltage Terminal. Drive this terminal with a low impedance voltage source to level shift the output.
Output Terminal.
Positive Power Supply Terminal.
Rev. 0 | Page 7 of 20
AD8421-EP
Enhanced Product
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, VS = ±15 V, VREF = 0 V, RL = 2 kΩ, unless otherwise noted.
600
600
500
500
300
300
200
200
100
100
–40
–20
0
20
40
60
INPUT OFFSET VOLTAGE (µV)
0
–400
1000
1200
800
UNITS
1500
900
400
300
200
–0.5
0
0.5
1.0
1.5
0
100
200
300
400
600
600
2.0
INPUT BIAS CURRENT (nA)
0
–2.0
11139-004
UNITS
1200
–1.0
–100
Figure 7. Typical Distribution of Output Offset Voltage
1800
–1.5
–200
OUTPUT OFFSET VOLTAGE (µV)
Figure 4. Typical Distribution of Input Offset Voltage
0
–2.0
–300
–1.5
–1.0
–0.5
0
0.5
1.0
1.5
2.0
INPUT OFFSET CURRENT (nA)
11139-007
0
–60
11139-006
UNITS
400
11139-003
UNITS
400
Figure 8. Typical Distribution of Input Offset Current
Figure 5. Typical Distribution of Input Bias Current
1600
1400
1400
1200
1200
1000
UNITS
600
400
400
200
200
–15
–10
–5
0
5
10
PSRR (µV/V)
15
20
0
–120
–90
–60
–30
0
30
60
90
CMRR (µV/V)
Figure 9. Typical Distribution of CMRR (G = 1)
Figure 6. Typical Distribution of PSRR (G = 1)
Rev. 0 | Page 8 of 20
120
11139-008
0
–20
800
600
11139-005
UNITS
1000
800
Enhanced Product
AD8421-EP
15
4
G=1
G = 100
VS = ±15V
3
COMMON-MODE VOLTAGE (V)
VS = ±12V
5
0
–5
–10
0
5
10
15
–1
–2
–4
–4
–3
–2
–1
0
1
2
3
4
OUTPUT VOLTAGE (V)
Figure 10. Input Common-Mode Voltage vs. Output Voltage;
VS = ±12 V and ±15 V (G = 1)
Figure 13. Input Common-Mode Voltage vs. Output Voltage;
VS = ±2.5 V and ±5 V (G = 100)
40
G=1
VS = ±5V
3
30
VS = 5V
G=1
20
2
INPUT CURRENT (mA)
VS = ±2.5V
1
0
–1
10
0
–10
–20
–2
–30
–3
–2
–1
0
1
2
3
4
OUTPUT VOLTAGE (V)
–40
–35 –30 –25 –20 –15 –10 –5
11139-010
–3
–4
0
5
10 15 20 25 30 35 40
INPUT VOLTAGE (V)
Figure 11. Input Common-Mode Voltage vs. Output Voltage;
VS = ±2.5 V and ±5 V (G = 1)
11139-013
COMMON-MODE VOLTAGE (V)
VS = ±2.5V
0
11139-012
–5
11139-009
–10
OUTPUT VOLTAGE (V)
Figure 14. Input Overvoltage Performance; G = 1, +VS = 5 V, −VS = 0 V
15
30
VS = ±15V
G=1
VS = ±15V
G = 100
20
10
INPUT CURRENT (mA)
VS = ±12V
5
0
–5
–15
–15
10
0
–10
–20
–10
–10
–5
0
5
10
15
OUTPUT VOLTAGE (V)
11139-011
COMMON-MODE VOLTAGE (V)
1
–3
–15
–15
4
VS = ±5V
2
Figure 12. Input Common-Mode Voltage vs. Output Voltage;
VS = ±12 V and ±15 V (G = 100)
–30
–25
–20
–15
–10
–5
0
5
10
15
20
25
INPUT VOLTAGE (V)
Figure 15. Input Overvoltage Performance; G = 1, VS = ±15 V
Rev. 0 | Page 9 of 20
11139-014
COMMON-MODE VOLTAGE (V)
10
AD8421-EP
Enhanced Product
160
40
GAIN = 1000
140
GAIN = 100
POSITIVE PSRR (dB)
120 GAIN = 10
10
0
–10
100 GAIN = 1
80
60
–20
40
–30
20
–40
–35 –30 –25 –20 –15 –10 –5
0
5
10 15 20 25 30 35 40
INPUT VOLTAGE (V)
0
0.1
11139-015
INPUT CURRENT (mA)
20
1
100
1k
FREQUENCY (Hz)
10k
100k
1M
100k
1M
Figure 19. Positive PSRR vs. Frequency
Figure 16. Input Overvoltage Performance; +VS = 5 V, −VS = 0 V, G = 100
160
30
GAIN = 1000
VS = ±15V
G = 100
140 GAIN = 100
20
GAIN = 10
NEGATIVE PSRR (dB)
120
INPUT CURRENT (mA)
10
11139-018
30
VS = 5V
G = 100
10
0
–10
GAIN = 1
100
80
60
40
–20
–10
–5
0
5
10
15
20
25
INPUT VOLTAGE (V)
0
0.1
1
2.0
60
1.5
50
1.0
40
0.5
30
GAIN (dB)
70
0
–0.5
20
0
–1.5
–10
–2.0
–20
–4
–2
0
2
4
6
8
10
12
COMMON-MODE VOLTAGE (V)
14
10k
GAIN = 1000
GAIN = 100
GAIN = 10
10
–1.0
11139-017
BIAS CURRENT (nA)
2.5
–6
100
1k
FREQUENCY (Hz)
Figure 20. Negative PSRR vs. Frequency
Figure 17. Input Overvoltage Performance; VS = ±15 V, G = 100
–2.5
–12 –10 –8
10
11139-019
–15
GAIN = 1
–30
100
1k
10k
100k
FREQUENCY (Hz)
Figure 21. Gain vs. Frequency
Figure 18. Input Bias Current vs. Common-Mode Voltage
Rev. 0 | Page 10 of 20
1M
10M
11139-020
–20
11139-016
–30
–25
20
Enhanced Product
160
6
GAIN = 1000
120
GAIN = 100
4
GAIN = 10
2
BIAS CURRENT (nA)
140
GAIN = 1
100
80
60
REPRESENTATIVE SAMPLES
0
–2
–4
–6
1
10
100
1k
10k
100k
FREQUENCY (Hz)
–8
–55 –40 –25 –10
11139-021
40
0.1
5
20
35
50
65
80
95
110 125
TEMPERATURE (°C)
11139-125
CMRR (dB)
AD8421-EP
Figure 25. Input Bias Current vs. Temperature
Figure 22. CMRR vs. Frequency
100
160
GAIN = 1000
80
140
REPRESENTATIVE SAMPLES
GAIN = 1
60
CMRR (dB)
120
GAIN ERROR (µV/V)
GAIN = 100
GAIN = 10
100
GAIN = 1
80
40
20
0
–20
–40
–60
60
10
100
1k
10k
100k
FREQUENCY (Hz)
–100
–55 –40 –25 –10
20
35
50
65
80
95
110 125
110 125
TEMPERATURE (°C)
Figure 26. Gain vs. Temperature (G = 1)
Figure 23. CMRR vs. Frequency, 1 kΩ Source Imbalance
15
2.0
REPRESENTATIVE SAMPLES
GAIN = 1
10
1.5
CMRR (µV/V)
5
1.0
0.5
0
–5
0
–0.5
–10
0
5
10
15
20
25
30
35
40
45
50
WARM-UP TIME (Seconds)
11139-023
CHANGE IN INPUT OFFSET VOLTAGE (µV)
5
11139-126
1
11139-022
40
0.1
11139-127
–80
–15
–55 –40 –25 –10
5
20
35
50
65
80
95
TEMPERATURE (°C)
Figure 27. CMRR vs. Temperature (G = 1)
Figure 24. Change in Input Offset Voltage (VOSI) vs. Warm-Up Time
Rev. 0 | Page 11 of 20
AD8421-EP
3.0
Enhanced Product
45
VS = ±15V
40
2.5
–SR
2.0
30
SLEW RATE (V/µs)
SUPPLY CURRENT (mA)
35
1.5
1.0
+SR
25
20
15
10
0.5
20
35
50
65
80
95
110 125
TEMPERATURE (°C)
0
–55 –40 –25 –10
+VS
INPUT VOLTAGE (V)
REFERRED TO SUPPLY VOLTAGES
20
0
–20
–40
–60
–80
ISHORT–
5
20
35
50
65
65
80
95
110 125
–1.0
–1.5
–2.0
–2.5
+2.5
+2.0
+1.5
+1.0
+0.5
80
95
110 125
TEMPERATURE (°C)
–VS
11139-129
SHORT CIRCUIT CURRENT (mA)
ISHORT+
–120
–55 –40 –25 –10
50
–55°C
–40°C
+25°C
+85°C
+105°C
+125°C
–0.5
–100
35
Figure 31. Slew Rate vs. Temperature, VS = ±5 V (G = 1)
80
40
20
TEMPERATURE (°C)
Figure 28. Supply Current vs. Temperature (G = 1)
60
5
2
4
6
8
10
12
14
16
18
SUPPLY VOLTAGE (±VS)
11139-132
5
11139-128
0
–55 –40 –25 –10
11139-131
5
Figure 32. Input Voltage Limit vs. Supply Voltage
Figure 29. Short-Circuit Current vs. Temperature (G = 1)
15
40
–SR
35
10
OUTPUT VOLTAGE SWING (V)
+SR
25
20
15
10
5
0
–5
+125°C
+105°C
+85°C
+25°C
–40°C
–55°C
–10
0
–55 –40 –25 –10
5
20
35
50
65
80
95
110 125
TEMPERATURE (°C)
–15
100
1k
10k
LOAD (Ω)
Figure 33. Output Voltage Swing vs. Load Resistance
Figure 30. Slew Rate vs. Temperature, VS = ±15 V (G = 1)
Rev. 0 | Page 12 of 20
100k
11139-135
5
11139-130
SLEW RATE (V/µs)
30
Enhanced Product
AD8421-EP
+VS
–2
–4
GAIN = 1000
80
60
NONLINEARITY (ppm)
–6
+6
+2
–20
–40
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
–8
–6
–4
–2
0
2
4
6
8
10
OUTPUT VOLTAGE (V)
11139-072
0.01
11139-136
0
–100
–10
Figure 37. Gain Nonlinearity (G = 1000), RL = 600 Ω, VOUT = ±10 V
Figure 34. Output Voltage Swing vs. Output Current
5
100
GAIN = 1
GAIN = 1000
4
80
3
60
2
40
NONLINEARITY (ppm)
1
0
–1
–2
–3
20
RL = 600Ω
0
–20
–40
–60
RL = 2kΩ
RL = 10kΩ
–5
–10
–8
–6
–4
–2
0
2
4
6
8
–80
10
OUTPUT VOLTAGE (V)
–100
–5
11139-035
–4
VOLTAGE NOISE SPECTRAL DENSITY (nV/√Hz)
3
2
1
RL = 600Ω
–1
–2
–3
–4
–2
0
2
4
6
OUTPUT VOLTAGE (V)
8
10
11139-036
–4
–6
–1
0
1
2
3
4
5
1k
GAIN = 1
4
–8
–2
Figure 38. Gain Nonlinearity (G = 1000), RL = 600 Ω, VOUT = ±5 V
5
–5
–10
–3
OUTPUT VOLTAGE (V)
Figure 35. Gain Nonlinearity (G = 1), RL = 10 kΩ, 2 kΩ
0
–4
11139-073
NONLINEARITY (ppm)
RL = 600Ω
0
–80
OUTPUT CURRENT (A)
NONLINEARITY (ppm)
20
–60
+4
–VS
40
Figure 36. Gain Nonlinearity (G = 1), RL = 600 Ω
100
GAIN = 1
GAIN = 10
10
GAIN = 100
GAIN = 1000
1
1
10
100
1k
10k
100k
FREQUENCY (Hz)
Figure 39. RTI Voltage Noise Spectral Density vs. Frequency
Rev. 0 | Page 13 of 20
11139-037
OUTPUT VOLTAGE SWING (V)
REFERRED TO SUPPLY VOLTAGES
100
–55°C
–40°C
+25°C
+85°C
+105°C
+125°C
AD8421-EP
Enhanced Product
30
G = 1000, 40nV/DIV
OUTPUT VOLTAGE (V p-p)
25
G = 1, 1µV/DIV
15
10
0
10
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
Figure 40. 0.1 Hz to 10 Hz RTI Voltage Noise (G = 1, G = 1000)
Figure 43. Large Signal Frequency Response
1k
5V/DIV
720ns TO 0.01%
1.12µs TO 0.001%
100
1
10
100
1k
10k
100k
FREQUENCY (Hz)
1µs/DIV
11139-039
10
0.1
11139-041
0.002%/DIV
Figure 41. Current Noise Spectral Density vs. Frequency
Figure 44. Large Signal Pulse Response and Settling Time (G = 1),
10 V Step, VS = ±15 V, RL = 2 kΩ, CL = 100 pF
5V/DIV
420ns TO 0.01%
604ns TO 0.001%
5pA/DIV
1s/DIV
1µs/DIV
Figure 42. 0.1 Hz to 10 Hz Current Noise
11139-042
0.002%/DIV
11139-040
CURRENT NOISE (fA/√Hz)
10k
Figure 45. Large Signal Pulse Response and Settling Time (G = 10),
10 V Step, VS = ±15 V, RL = 2 kΩ, CL = 100 pF
Rev. 0 | Page 14 of 20
11139-045
5
11139-038
1s/DIV
20
Enhanced Product
AD8421-EP
GAIN = 1
5V/DIV
704ns TO 0.01%
764ns TO 0.001%
50mV/DIV
Figure 46. Large Signal Pulse Response and Settling Time (G = 100),
10 V Step, VS = ±15 V, RL = 2 kΩ, CL = 100 pF
1µs/DIV
11139-046
1µs/DIV
11139-043
0.002%/DIV
Figure 49. Small Signal Pulse Response (G = 1), RL = 600 Ω, CL = 100 pF
GAIN = 10
5V/DIV
3.8µs TO 0.01%
5.76µs TO 0.001%
50mV/DIV
Figure 47. Large Signal Pulse Response and Settling Time (G = 1000),
10 V Step, VS = ±15 V, RL = 2 kΩ, CL = 100 pF
1µs/DIV
11139-047
4µs/DIV
11139-044
0.002%/DIV
Figure 50. Small Signal Pulse Response (G = 10), RL = 600 Ω, CL = 100 pF
2500
GAIN = 100
1500
SETTLED TO 0.001%
1000
20mV/DIV
GAIN = 1
0
2
4
6
8
10
12
14
16
18
20
STEP SIZE (V)
Figure 48. Settling Time vs. Step Size (G = 1), RL = 2 kΩ, CL = 100 pF
1µs/DIV
11139-048
SETTLED TO 0.01%
500
11139-054
SETTLING TIME (ns)
2000
Figure 51. Small Signal Pulse Response (G = 100), RL = 600 Ω, CL = 100 pF
Rev. 0 | Page 15 of 20
AD8421-EP
Enhanced Product
–40
GAIN = 1000
–50
–60
NO LOAD
RL = 2kΩ
RL = 600Ω
VOUT = 10V p-p
AMPLITUDE (dBc)
–70
–80
–90
–100
–110
–120
11139-049
–130
2µs/DIV
–140
–150
10
100
1k
10k
FREQUENCY (Hz)
Figure 52. Small Signal Pulse Response (G = 1000), RL = 600 Ω, CL = 100 pF
20pF 50pF
NO LOAD
100pF
11139-056
20mV/DIV
Figure 55. Third Harmonic Distortion vs. Frequency (G = 1)
–40
G=1
–50
NO LOAD
RL = 2kΩ
RL = 600Ω
VOUT = 10V p-p
AMPLITUDE (dBc)
–60
–70
–80
–90
1µs/DIV
–110
–120
10
RL ≥ 600Ω
Figure 56. Second Harmonic Distortion vs. Frequency (G = 1000)
–40
VOUT = 10V p-p
–70
–60
AMPLITUDE (dBc)
–80
–90
–100
–110
–120
–70
–80
–90
–100
–130
–110
–140
100
1k
10k
FREQUENCY (Hz)
11139-055
AMPLITUDE (dBc)
VOUT = 10V p-p
RL ≥ 600Ω
–50
–60
–150
10
10k
Figure 54. Second Harmonic Distortion vs. Frequency (G = 1)
–120
10
100
1k
10k
FREQUENCY (Hz)
Figure 57. Third Harmonic Distortion vs. Frequency (G = 1000)
Rev. 0 | Page 16 of 20
11139-076
–50
1k
FREQUENCY (Hz)
Figure 53. Small Signal Response with Various Capacitive Loads (G = 1),
RL = Infinity
–40
100
11139-075
50mV/DIV
11139-053
–100
Enhanced Product
–20
–30
–40
G
G
G
G
AD8421-EP
=1
= 10
= 100
= 1000
VOUT = 10V p-p
RL = 2kΩ
–60
–70
–80
–90
–100
–110
–120
–130
–140
10
100
1k
FREQUENCY (Hz)
10k
11139-077
AMPLITUDE (dBc)
–50
Figure 58. THD vs. Frequency
Rev. 0 | Page 17 of 20
AD8421-EP
Enhanced Product
OUTLINE DIMENSIONS
3.20
3.00
2.80
8
3.20
3.00
2.80
1
5.15
4.90
4.65
5
4
PIN 1
IDENTIFIER
0.65 BSC
0.95
0.85
0.75
15° MAX
1.10 MAX
0.40
0.25
6°
0°
0.23
0.09
0.80
0.55
0.40
COMPLIANT TO JEDEC STANDARDS MO-187-AA
10-07-2009-B
0.15
0.05
COPLANARITY
0.10
Figure 59. 8-Lead Mini Small Outline Package [MSOP]
(RM-8)
Dimensions shown in millimeters
ORDERING GUIDE
Model 1
AD8421TRMZ-EP
AD8421TRMZ-EP-R7
1
Temperature Range
−55°C to +125°C
−55°C to +125°C
Package Description
8-Lead Mini Small Outline Package [MSOP]
8-Lead Mini Small Outline Package [MSOP]
Z = RoHS Compliant Part.
Rev. 0 | Page 18 of 20
Package Option
RM-8
RM-8
Branding
Y4T
Y4T
Enhanced Product
AD8421-EP
NOTES
Rev. 0 | Page 19 of 20
AD8421-EP
Enhanced Product
NOTES
©2013 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D11139-0-5/12(0)
Rev. 0 | Page 20 of 20