High-precision current shunt monitors are designed by Diodes to measure small sense voltages across a wide common-mode voltage range in electric vehicles (EVs). The ZXCT21xQ family of single stage instrumentation amplifiers is suitable for a range of automotive applications including current sensing of load/rail currents in brushless DC (BLDC) motor controllers, e-compressors, high power DC/DC converters, on-board chargers (OBC), battery management systems (BMS), ADAS (advanced driver assistance systems) power supplies and wireless phone chargers.

The zero drift core (typical ±100nV/°C) provide a low offset voltage (±30μV) and gain error (±0.5% and ±0.8%) to enable current sensing across the shunt, with maximum voltage drops down to 10mV (full-scale). According to Diodes, small-value sense resistors can be used in high accuracy monitoring of large magnitude currents, while reducing the power lost during measurement. The low quiescent current consumption of 100μA (maximum) also helps to minimise power consumption, adds the company.

A rail-to-rail common mode sense voltage range of 0V to 26V enables both high side and low side precision current measurement and there is an REF pin which enables bi-directional current flow measurement. The current shunt monitors have six voltage gain options (50V/V, 75V/V, 100V/V, 200V/V, 500V/V, and 1000V/V), each with three accuracy variants.

All devices in the ZXCT21xQ series are AEC-Q100 Grade 1-qualified, manufactured in IATF 16949 certified facilities and support PPAP documentation. Operating range is -40 to 125°C. They are available in an industry-standard SOT363 package.