INA225 Current-Shunt Monitor

By Texas Instruments 89

INA225 Current-Shunt Monitor

Texas Instruments' INA225 is a voltage-output, current-sense amplifier that senses drops across current-sensing resistors at common-mode voltages that can vary from 0 to 36 V, independent of the supply voltage. The device is a bidirectional, current-shunt monitor that allows an external reference to be used to measure current flowing in both directions across a current-sensing resistor.

Four discrete gain levels are selectable using the two gain-select terminals (GS0 and GS1) to program gains of 25 V/V, 50 V/V, 100 V/V, and 200 V/V. The low-offset, zero-drift architecture and precision gain values enable current-sensing with maximum drops across the shunt as low as 10 mV of full-scale, while maintaining very high accuracy measurements over the entire operating temperature range.

The device operates from a single +2.7 V to +36 V power supply, drawing a maximum of 350 µA of supply current. The device is specified over the extended operating temperature range (–40°C to +125°C), and is offered in an MSOP-8 package.

  • Wide common-mode range: 0 V to 36 V
  • Offset voltage: ±150 µV (Max, all gains)
  • Offset voltage drift: 0.5 µV/°C (Max)
  • Gain accuracy, over temperature (Max):
    • 25 V/V, 50 V/V: ±0.15%
    • 100 V/V: ±0.2%
    • 200 V/V: ±0.3%
    • 10 ppm/°C gain drift
  • 250 kHz bandwidth (gain = 25 V/V)
  • Programmable gains:
    • G1 = 25 V/V
    • G2 = 50 V/V
    • G3 = 100 V/V
    • G4 = 200 V/V
  • Quiescent current: 350 µA (Max)
  • Power supplies
  • Motor control
  • Computers
  • Telecom equipment
  • Power management
  • Test and measurement

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