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INA333 Instrumentation Amplifier

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by Ray

Micropower, zero-drift, precision instrumentation amplifier with a single-resistor gain set.

instrumentation-ampzero-driftprecisionlow-powertimsop-8
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INA333

Texas Instruments · Instrumentation Amplifier · MSOP-8

The INA333 is a micropower, zero-drift instrumentation amplifier. A single external resistor sets gain from 1 to 1000, and the zero-drift topology gives low offset and drift for precision measurement of bridge sensors, thermocouples, and biopotential signals like ECG.

Pinout

Pin Name Type Function
1 RG passive Gain-setting pin. Place an external gain resistor RG between pins 1 and 8 to set gain G = 1 + (100 kΩ / RG). Leave open for unity gain (G = 1).
2 VIN- input Negative (inverting) analog input. Input voltage range is (V-) + 0.1 V to (V+) - 0.1 V; input bias current is ±70 pA typ (±200 pA max).
3 VIN+ input Positive (non-inverting) analog input. Input voltage range is (V-) + 0.1 V to (V+) - 0.1 V; input bias current is ±70 pA typ (±200 pA max).
4 V- power_in Negative power supply. Single-supply range +1.8 V to +5.5 V (with V- = GND) or dual-supply ±0.9 V to ±2.75 V. Absolute maximum supply span (V+) - (V-) = 7 V.
5 REF input Reference input. Sets the output zero (offset) voltage. Must be driven from a low-impedance source or connected to ground; internal RIN ≈ 300 kΩ, so a driving impedance error will degrade CMRR and gain accuracy.
6 VOUT output Amplifier output. Rail-to-rail output swings to within 50 mV of the supply rails with RL = 10 kΩ; short-circuit current is limited to -40/+5 mA.
7 V+ power_in Positive power supply. Single-supply range +1.8 V to +5.5 V or dual-supply ±0.9 V to ±2.75 V. Quiescent current is 50 µA typ (75 µA max).
8 RG passive Gain-setting pin (paired with pin 1). Place an external gain resistor RG between pins 1 and 8 to set gain G = 1 + (100 kΩ / RG). Leave open for unity gain.

Key specifications

Parameter Value
Type Instrumentation amplifier (3-op-amp, zero-drift)
Gain 1 to 1000 (single external resistor)
Input offset voltage 25 uV typ, 75 uV max
Offset drift 0.1 uV/C typ
Supply voltage 1.8 V to 5.5 V
Supply current 50 uA typ
CMRR 100 dB min (G >= 10)
Operating temperature -40 C to 85 C

Ordering variants

Same part, different packaging or reel option.

  • INA333IDGKR
  • INA333IDGKT
  • INA333IDRGR
  • INA333IDRGT

CAD (KiCad official)

  • Symbol: ina333.kicad_sym
  • Footprint: ina333.kicad_mod
  • 3D model: MSOP-8 body from KiCad Package_SO/MSOP-8_3x3mm_P0.65mm.

Provenance

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

  • Datasheet: Texas Instruments datasheet (35 pp, sha256 446404e162fbb07e, 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