Datasheet AD8420 (Analog Devices)

Wide Supply Range, Micropower, Rail-to-Rail Instrumentation Amplifier Data Sheet AD8420 FEATURES PIN CONFIGURATION Maximum supply current: 90 μA AD8420 Minimum CMRR: 100 dB NC 1 8 VOUT Drives heavy capacitive loads: ~700 pF +IN 2 + – 7 FB Rail-to-rail output –IN 3 – + 6 REF
1 00
–V TOP VIEW S 4 5 +VS
5-
Input voltage range goes below ground (Not to Scale)
994 0
Gain set with 2 external resistors
Figure 1.
Can achieve low gain drift at any gain Very wide power supply range Single supply: 2.7 V to 36 V Table 1. Instrumentation Amplifiers by Category1 Dual supply: ±2.7 V to ±18 V General Military Low Digital Bandwidth (G = 100): 2.5 kHz Purpose Zero Drift Grade Power Gain Input voltage noise: 55 nV/√Hz
AD8221, AD8222 AD8231 AD620 AD8420 AD8250
High dc precision
AD8220, AD8224 AD8290 AD621 AD8235 AD8251
Maximum offset voltage: 125 μV
AD8236
Maximum offset drift: 1 μV/°C
AD8226, AD8227 AD8293G80, AD524 AD627 AD8253
Maximum differential input voltage: ±1 V
AD8293G160
8-lead MSOP package
AD8228 AD8553 AD526 AD8226 AD8231 AD8227
APPLICATIONS
AD8295, AD8224 AD8556 AD624 AD623
Bridge amplifiers
AD8557 AD8223
Pressure measurement
1
Medical instrumentation
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Portable data acquisition Multichannel systems GENERAL DESCRIPTION
The AD8420 is a low cost, micropower, wide supply range, Single-supply operation, micropower current consumption, and instrumentation amplifier with a rail-to-rail output and a novel rail-to-rail output swing make the AD8420 ideal for battery- architecture that allows for extremely flexible design. It is optimized powered applications. Its rail-to-rail output stage maximizes to amplify small differential voltages in the presence of large dynamic range when operating from low supply voltages. Dual- common-mode signals. supply operation (±15 V) and low power consumption make The AD8420 is based on an indirect current feedback architecture the AD8420 ideal for a wide variety of applications in medical that gives it an excellent input common-mode range. Unlike or industrial instrumentation. conventional instrumentation amplifiers, the AD8420 can easily The AD8420 is available in an 8-lead MSOP package. Performance amplify signals at or even slightly below ground without requiring is specified over the full temperature range of −40°C to +85°C, dual supplies. The AD8420 has rail-to-rail output, and the output and the device is operational from −40°C to +125°C. voltage swing is completely independent of the input common- mode voltage.
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Document Outline FEATURES APPLICATIONS PIN CONFIGURATION GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION ARCHITECTURE SETTING THE GAIN GAIN ACCURACY INPUT VOLTAGE RANGE INPUT PROTECTION Input Voltages Beyond the Rails Large Differential Input Voltage LAYOUT Common-Mode Rejection Ratio over Frequency Power Supplies Reference DRIVING THE REFERENCE PIN INPUT BIAS CURRENT RETURN PATH RADIO FREQUENCY INTERFERENCE (RFI) OUTPUT BUFFERING APPLICATIONS INFORMATION AD8420 IN ELECTROCARDIOGRAPHY (ECG) CLASSIC BRIDGE CIRCUIT 4 mA TO 20 mA SINGLE-SUPPLY RECEIVER OUTLINE DIMENSIONS ORDERING GUIDE