High-side current sense with AEC-Q100 qualification
The INA138QPWRQ1 is a high-side current monitor from Texas Instruments, part of the Automotive AEC-Q100 series. It measures load current by sensing the voltage drop across a shunt resistor on the supply rail, outputting a proportional current that can be converted to a voltage with a single external resistor. Rated for a 2.7 V to 36 V input range, it monitors bus voltages from a 3.3 V logic rail up to a 24 V automotive battery line without needing an external regulator.
The part is ROHS3 compliant, so it meets the material restriction requirements for European and global markets without a waiver.
What the ±0.5% accuracy means for your BOM
The ±0.5% accuracy is the total output error over temperature, not just at 25°C. Because it is a high-side monitor, the load remains referenced to ground — no need for a separate low-side sense resistor that would lift the load's ground reference. The output current is single-ended, so a single ADC channel on the microcontroller reads the load current directly.