The INA240 is a voltage-output current-sense amplifier with enhanced PWM rejection, which lets it read motor current accurately even while the bus is switching, across a common-mode range of −4 V to 80 V. It is the motor-drive version of the simpler INA180. Figures are from the Texas Instruments INA240 datasheet SBOS662C.
Key specifications
| Common-mode | −4 to 80 V |
|---|---|
| Gains | 20, 50, 100, 200 V/V |
| Gain error | 0.20% max |
| Offset | ±25 µV max |
| Supply | 2.7–5.5 V |
| Supply current | 2.4 mA max |
What the datasheet promises
| Item | Datasheet value |
|---|---|
| Common-mode range | −4 V to 80 V, independent of the supply voltage |
| PWM rejection | Enhanced, to suppress large common-mode dV/dt transients in motor and solenoid drives |
| Common-mode rejection | 132 dB at DC; 93 dB at 50 kHz |
| Gain options | A1: 20 V/V; A2: 50 V/V; A3: 100 V/V; A4: 200 V/V |
| Gain error | 0.20 percent maximum |
| Gain drift | 2.5 ppm/°C maximum |
| Offset voltage | ±25 µV maximum; drift 250 nV/°C maximum |
| Supply | 2.7 to 5.5 V, 2.4 mA maximum |
| Temperature | −40 to 125 °C |
| Packages | TSSOP-8 and SOIC-8 |
Because the offset is so low, the datasheet says the shunt can drop as little as 10 mV at full scale, which keeps shunt heating down. The negative common-mode range lets the part ride through the flyback period in solenoid and inductive loads.
Using it on a robot
- Sense the phase or bridge current of a motor driver, with the shunt in the motor path, and feed the output to an ADC.
- Choose the gain so the largest expected current, including stall, stays within the ADC range.
- For a lower-cost, simpler design where PWM is not a concern, use the INA180; for I2C readout of voltage and power, the INA226.
Sources and further reading
- Texas Instruments INA240 datasheet (SBOS662C) — common-mode range, PWM rejection, CMRR, gains, accuracy, supply and packages above.
Last reviewed: November 2026. Limits are from the Texas Instruments datasheet; breakout boards and modules vary. No price is quoted because it has not been checked.
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