Datasheet AD8222 (Analog Devices)

Precision, Dual-Channel Instrumentation Amplifier Data Sheet AD8222 FEATURES FUNCTIONAL BLOCK DIAGRAM Two channels in small 4 mm × 4 mm LFCSP S T1 T2 S Gain set with 1 resistor per amplifier (G = 1 to 10,000) +V OU OU –V 16 15 14 13 Low noise AD8222 8 nV/√Hz at 1 kHz –IN1 1 12 –IN2 0.25 µV p-p (0.1 Hz to 10 Hz) RG1 2 11 RG2 High accuracy dc performance (B grade) RG1 3 10 RG2 +IN1 4 9 +IN2 60 µV maximum input offset voltage 0.3 µV/°C maximum input offset drift 5 6 7 8 1.0 nA maximum input bias current S 1 2 S
001
F F +V –V 126 dB minimum CMRR (G = 100) RE RE
05947- Figure 1.
Excellent ac performance 140 kHz bandwidth (G = 100) 13 µs settling time to 0.001% Differential output option (single channel) Fully specified Adjustable common-mode output Supply range: ±2.3 V to ±18 V APPLICATIONS Multichannel data acquisition for ECG and medical instrumentation Industrial process controls
AD8222 maintains a minimum CMRR of 80 dB to 4 kHz for all
Wheatstone bridge sensors
grades at G = 1. High CMRR over frequency allows the AD8222
Differential drives for
to reject wideband interference and line harmonics, greatly
High resolution input ADCs
simplifying filter requirements. The AD8222 also has a typical
Remote sensors
CMRR drift over temperature of just 0.07 µV/V/°C at G = 1.
GENERAL DESCRIPTION
The AD8222 operates on both single and dual supplies and only The AD8222 is a dual-channel, high performance instrumentation requires 2.2 mA maximum supply current for both amplifiers. amplifier that requires only one external resistor per amplifier It is specified over the industrial temperature range of −40°C to to set gains of 1 to 10,000. +85°C and is fully RoHS compliant. The AD8222 is the first dual-instrumentation amplifier in the For a single-channel version, see the AD8221. small 4 mm × 4mm LFCSP. It requires the same board area as a
Table 1. Instrumentation Amplifiers by Category1
typical single instrumentation amplifier. The smaller package
General- Military Low High
allows a 2× increase in channel density and a lower cost per
Purpose Zero Drift Grade Power Speed PGA
channel, all with no compromise in performance. AD8220 AD8231 AD620 AD8235 AD8250 AD8221 AD8290 AD621 AD8236 AD8251 The AD8222 can also be configured as a single-channel, differen- AD8222 AD8293G80 AD524 AD627 AD8253 tial output instrumentation amplifier. Differential outputs provide AD8224 AD8553 AD526 AD623 high noise immunity, which can be useful when the output AD8228 AD8556 AD624 AD8223 signal must travel through a noisy environment, such as with AD8295 AD8557 AD8226 remote sensors. The configuration can also be used to drive AD8227 differential input analog-to-digital converters (ADCs). The 1 See www.analog.com for the latest selection of instrumentation amplifiers.
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Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE Maximum Power Dissipation ESD CAUTION PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION AMPLIFIER ARCHITECTURE GAIN SELECTION REFERENCE TERMINAL PACKAGE CONSIDERATIONS Package Without Thermal Pad Package with Thermal Pad LAYOUT Common-Mode Rejection Over Frequency Reference Power Supplies INPUT BIAS CURRENT RETURN PATH INPUT PROTECTION Input Voltages Beyond the Rails Differential Input Voltages at High Gains RF INTERFERENCE COMMON-MODE INPUT VOLTAGE RANGE APPLICATIONS INFORMATION DIFFERENTIAL OUTPUT Setting the Common-Mode Voltage 2-Channel Differential Output Using a Dual Op Amp DRIVING A DIFFERENTIAL INPUT ADC RFI and Antialiasing Filter Second Antialiasing Filter Reference PRECISION STRAIN GAGE DRIVING CABLING OUTLINE DIMENSIONS ORDERING GUIDE