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AD620 Instrumentation Amplifier

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by Ray

Low-power, low-noise instrumentation amplifier with a single-resistor gain set.

instrumentation-ampin-amplow-noiseprecisionadisoic-8
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README

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AD620

Analog Devices · Instrumentation Amplifier · SOIC-8

The AD620 is a low-power, low-noise instrumentation amplifier that sets gain (1 to 1000) with a single external resistor. Its high common-mode rejection, low input bias current, and low noise make it a long-standing choice for amplifying small differential signals from bridge sensors, thermocouples, and biopotential measurements like ECG.

Pinout

Pin Name Type Function
1 RG passive Gain-setting resistor terminal. Connect an external resistor RG between pins 1 and 8 to program the gain: G = 1 + (49.4 kΩ / RG). Leave open for unity gain (G = 1).
2 -IN input Inverting analog input of the instrumentation amplifier. Differential input impedance 10 GΩ
3 +IN input Noninverting analog input of the instrumentation amplifier. Differential input impedance 10 GΩ
4 -VS power_in Negative supply rail. Operating range ±2.3 V to ±18 V (bipolar) referenced to +VS. Quiescent current 0.9 mA typ, 1.3 mA max.
5 REF input Reference input. Sets the DC level of the output; the output voltage is measured with respect to this pin. Input resistance 20 kΩ typical, input current 50 µA (60 µA max) when VIN+ = VREF = 0. Must be driven from a low-impedance source to preserve CMRR.
6 OUTPUT output Amplifier output. Output voltage = G × (V+IN - V-IN) + VREF. Output swing to within ~1.2 V of the rails at ±15 V into 10 kΩ; short-circuit current ±18 mA.
7 +VS power_in Positive supply rail. Operating range ±2.3 V to ±18 V (bipolar). Quiescent current 0.9 mA typ, 1.3 mA max.
8 RG passive Gain-setting resistor terminal. Connect an external resistor RG between pins 1 and 8 to program the gain: G = 1 + (49.4 kΩ / RG). Leave open for unity gain (G = 1).

Key specifications

Parameter Value
Type Instrumentation amplifier
Gain 1 to 1000 (single external resistor)
Input offset voltage 50 uV max
Input noise 9 nV/sqrt(Hz) at 1 kHz
CMRR 100 dB min (G >= 10)
Supply voltage +-2.3 V to +-18 V
Supply current 1.3 mA max
Operating temperature -40 C to 85 C

Ordering variants

  • AD620AR
  • AD620ARZ
  • AD620AR-REEL
  • AD620ARZ-REEL
  • AD620AR-REEL7
  • AD620ARZ-REEL7
  • AD620BR
  • AD620BRZ
  • AD620BR-REEL
  • AD620BRZ-RL
  • AD620BR-REEL7
  • AD620BRZ-R7
  • AD620AN
  • AD620ANZ
  • AD620BN
  • AD620BNZ
  • AD620SQ/883B

CAD (KiCad official)

  • Symbol: ad620.kicad_sym
  • Footprint: ad620.kicad_mod
  • 3D model: SOIC-8 body from KiCad Package_SO/SOIC-8_3.9x4.9mm_P1.27mm.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Analog Devices datasheet (20 pp, sha256 83d076a7bf5e92d3, retrieved 2026-08-17, tier: manufacturer)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF