AD8420_12 Datasheet, PDF (1/28 Pages) Analog Devices – Wide Supply Range, Micropower,

Data Sheet
Wide Supply Range, Micropower,
Rail-to-Rail Instrumentation Amplifier
AD8420
FEATURES
Maximum supply current: 80 μA
Minimum CMRR: 100 dB
Drives heavy capacitive loads: ~700 pF
Rail-to-rail output
Input voltage range goes below ground
Gain set with 2 external resistors
Can achieve low gain drift at any gain
Very wide power supply range
Single supply: 2.7 V to 36 V
Dual supply: ±2.7 V to ±18 V
Bandwidth (G = 100): 2.5 kHz
Input voltage noise: 55 nV/√Hz
High dc precision
Maximum offset voltage: 125 μV
Maximum offset drift: 1 μV/°C
Maximum differential input voltage: ±1 V
8-lead MSOP package
APPLICATIONS
Bridge amplifiers
Pressure measurement
Medical instrumentation
Portable data acquisition
Multichannel systems
PIN CONFIGURATION
AD8420
NC 1
+IN 2
–IN 3
–V_S 4
+
–
–
+
TOP VIEW
(Not to Scale)
8 V_OUT
7 FB
6 REF
5 +V_S
Figure 1.
Table 1. Instrumentation Amplifiers by Category¹
Zero
General Purpose Drift
Military Low
Grade Power
AD8221, AD8222 AD8231 AD620
AD8220, AD8224 AD8290 AD621
AD8226, AD8227 AD8293 AD524
AD8228
AD8553 AD526
AD8295, AD8224 AD8556 AD624
AD8557
AD8420
AD8235,
AD8236
AD627
AD8226,
AD8227
AD623
AD8223
1 _{See www.analog.com for the latest instrumentation amplifiers.}
Digital
Gain
AD8250
AD8251
AD8253
AD8231
GENERAL DESCRIPTION
The AD8420 is a low cost, micropower, wide supply range,
instrumentation amplifier with a rail-to-rail output and a novel
architecture that allows for extremely flexible design. It is optimized
to amplify small differential voltages in the presence of large
common-mode signals.
The AD8420 is based on an indirect current feedback architecture
that gives it an excellent input common-mode range. Unlike
conventional instrumentation amplifiers, the AD8420 can easily
amplify signals at or even slightly below ground without requiring
dual supplies. The AD8420 has rail-to-rail output, and the output
voltage swing is completely independent of the input common-
mode voltage.
Single-supply operation, micropower current consumption, and
rail-to-rail output swing make the AD8420 ideal for battery-
powered applications. Its rail-to-rail output stage maximizes
dynamic range when operating from low supply voltages. Dual-
supply operation (±15 V) and low power consumption make
the AD8420 ideal for a wide variety of applications in medical
or industrial instrumentation.
The AD8420 is available in an 8-lead MSOP package. Performance
is specified over the full temperature range of −40°C to +85°C,
and the part is operational from −40°C to +125°C.
Rev. 0
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