INA250 current monitor IC includes the sense resistor

The INA250 from Texas Instruments is a voltage-output current-sensing amplifier integrated with a 0.002 Ω resistor — all within a 5.00 × 4.40 mm TSSOP16 package. It’s not the first time a device like this has been made, but previous versions have all been discontinued. Having a heat-generating resistor with your amp is tough, but now we think they got it right.

The INA250's shunt resistor has a 0.1% tolerance and the total maximum error over –40° to 125°C is just ±0.75%. The very low value of the sense resistor helps reduce heat and the amplifier is zero drift so there is just 15 ppm/°C delta over -40°C to 125°C. The amp has excellent CMRR of 110 db typical and common-mode range is –0.1 to 36 V, so it may be used for high-side sensing. And you don’t have to worry about running sense traces (for a Kelvin connection) around a circuit board.

The chip is fully specified for continuous currents up to ±10 A, or ±15 A at lower temperature and its bandwidth is 50 KHz.  The IC draws only 300 µA from a 2.7 to 36 V supply and it costs just $1.40 ea/1,000. An unbeatable combination.