AD8220_15 Datasheet, PDF (1/28 Pages) Analog Devices – JFET Input Instrumentation Amplifier

JFET Input Instrumentation Amplifier with
Rail-to-Rail Output in MSOP Package
AD8220
FEATURES
Low input currents
10 pA maximum input bias current (B grade)
0.6 pA maximum input offset current (B grade)
High CMRR
100 dB CMRR (minimum), G = 10 (B grade)
80 dB CMRR (minimum) to 5 kHz, G = 1 (B grade)
Excellent ac specifications and low power
1.5 MHz bandwidth (G = 1)
14 nV/√Hz input noise (1 kHz)
Slew rate: 2 V/μs
750 μA quiescent supply current (maximum)
Versatile
MSOP package
Rail-to-rail output
Input voltage range to below negative supply rail
4 kV ESD protection
4.5 V to 36 V single supply
±2.25 V to ±18 V dual supply
Gain set with single resistor (G = 1 to 1000)
Qualified for automotive applications
APPLICATIONS
Medical instrumentation
Precision data acquisition
Transducer interfaces
GENERAL DESCRIPTION
The AD8220 is the first single-supply, JFET input instrumentation
amplifier available in an MSOP package. Designed to meet the
needs of high performance, portable instrumentation, the AD8220
has a minimum common-mode rejection ratio (CMRR) of 86 dB
at dc and a minimum CMRR of 80 dB at 5 kHz for G = 1. Maxi-
mum input bias current is 10 pA and typically remains below
300 pA over the entire industrial temperature range. Despite the
JFET inputs, the AD8220 typically has a noise corner of only 10 Hz.
With the proliferation of mixed-signal processing, the number
of power supplies required in each system has grown. The AD8220
is designed to alleviate this problem. The AD8220 can operate
on a ±18 V dual supply, as well as on a single +5 V supply. Its
rail-to-rail output stage maximizes dynamic range on the low
voltage supplies common in portable applications. Its ability to
run on a single 5 V supply eliminates the need to use higher
voltage, dual supplies. The AD8220 draws a maximum of 750 μA
of quiescent current, making it ideal for battery powered devices.
PIN CONFIGURATION
–IN 1
R_G 2
R_G 3
+IN 4
AD8220
8 +V_S
7 V_OUT
6 REF
5 –V_S
TOP VIEW
(Not to Scale)
Figure 1.
10n
1n
100p
10p
1p
0.1p
I_BIAS
I_OS
–50 –25
0
25
50
75 100 125 150
TEMPERATURE (°C)
Figure 2. Input Bias Current and Offset Current vs. Temperature
Gain is set from 1 to 1000 with a single resistor. Increasing the
gain increases the common-mode rejection. Measurements that
need higher CMRR when reading small signals benefit when
the AD8220 is set for large gains.
A reference pin allows the user to offset the output voltage. This
feature is useful when interfacing with analog-to-digital converters.
The AD8220 is available in an MSOP that takes roughly half the
board area of an SOIC. Performance for the A and B grade is
specified over the industrial temperature range of −40°C to +85°C,
and the W grade is specified over the automotive temperature
range of −40°C to +125°C.
Rev. B
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