3 nV/Hz, Low Power
Instrumentation Amplifier
Enhanced Product
AD8421-EP
FEATURES PIN CONNECTION DIAGRAM
Specified from 55C to 125C
AD8421-EP
1 8
IN +V
S
0.9 V/C maximum input offset voltage drift
R 2 7 V
G OUT
5 ppm/C maximum gain drift (G = 1)
3 6
R REF
G
Low power
+IN 4 5 V
S
2.3 mA maximum supply current
Low noise
TOP VIEW
(Not to Scale)
3.2 nV/Hz maximum input voltage noise at 1 kHz
Figure 1.
200 fA/Hz current noise at 1 kHz
10
Excellent ac specifications
G = 100
2 MHz bandwidth (G = 100)
BEST AVAILABLE
0.6 s settling time to 0.001% (G = 10)
7mA LOW NOISE IN-AMP
1
80 dB minimum CMRR at 20 kHz (G = 1)
High precision dc performance
84 dB CMRR minimum (G = 1)
100n
2 nA maximum input bias current
Inputs protected to 40 V from opposite supply
BEST AVAILABLE
Gain set with a single resistor (G = 1 to 10,000)
1mA LOW POWER IN-AMP
10n
ENHANCED PRODUCT FEATURES AD8421
Supports defense and aerospace applications (AQEC standard) R NOISE ONLY
S
1n
Military temperature range (55C to +125C)
100 1k 10k 100k 1M
Controlled manufacturing baseline
SOURCE RESISTANCE, R ( )
S
One assembly/test site
Figure 2. Noise Density vs. Source Resistance
One fabrication site
Enhanced product change notification
Qualification data available on request
The AD8421-EP delivers 3 nV/Hz input voltage noise and
GENERAL DESCRIPTION
200 fA/Hz current noise with only 2 mA quiescent current,
making it an ideal choice for measuring low level signals. For
The AD8421-EP is a low cost, low power, extremely low noise,
applications with high source impedance, the AD8421-EP employs
ultralow bias current, high speed instrumentation amplifier that
innovative process technology and design techniques to provide
is ideally suited for a broad spectrum of signal conditioning and
noise performance that is limited only by the sensor.
data acquisition applications. This product features extremely
high CMRR, allowing it to extract low level signals in the presence
The AD8421-EP uses unique protection methods to ensure robust
of high frequency common-mode noise over a wide
inputs while still maintaining very low noise. This protection
temperature range.
allows input voltages up to 40 V from the opposite supply rail
without damage to the part.
The 10 MHz bandwidth, 35 V/s slew rate, and 0.6 s settling
time to 0.001% (G = 10) allow the AD8421-EP to amplify high
A single resistor sets the gain from 1 to 10,000. The reference
speed signals and excel in applications that require high channel
pin can be used to apply a precise offset to the output voltage.
count, multiplexed systems. Even at higher gains, the current
The AD8421-EP is specified over the military temperature range of
feedback architecture maintains high performance; for example,
55C to +125C. It is available in an 8-lead MSOP package.
at G = 100, the bandwidth is 2 MHz and the settling time is
Additional application and technical information can be found
0.8 s. The AD8421-EP has excellent distortion performance,
in the AD8421 data sheet.
making it suitable for use in demanding applications such as
vibration analysis.
Rev. 0 Document Feedback
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TOTAL NOISE DENSITY AT 1kHz (V/ Hz)
11139-001
11139-078AD8421-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
5/13Revision 0: Initial Version
Rev. 0 | Page 2 of 20