Current shunt monitors enable high-precision voltage sensing for rapid fault detection

Diodes Incorporated has announced the ZXCT18xQ series of automotive-compliant high-precision current shunt monitors. These single-stage instrumentation amplifiers accurately measure extremely small sense voltages across a broad range of common-mode voltages up to 26V while operating from a 2.7V to 5.5V supply. Automotive applications include ambient lighting control, battery management, heated seats, and other body control systems.

The ZXCT180Q current monitor supports unidirectional current measurement, whereas the ZXCT181Q also supports bidirectional flow. The ZXCT180Q has two pin assignment configurations – versions A and B – with its OUT-pin at different locations, permitting flexibility during PCB layout. When the ZXCT181Q is utilised for bidirectional current sensing, such as those found in a BMS, a voltage is introduced to the REF-pin. This action serves to offset the output voltage. For unidirectional current flow, the REF-pin of the ZXCT181Q is tied to GND.

The series has four fixed voltage gain options – 20V/V, 50V/V, 100V/V, and 200V/V. These devices measure voltages across shunts at common-mode voltages from -0.3V to 26V, independent of the supply voltage with a maximum supply current of 370µA. The devices support small-signal bandwidths as high as 400kHz at 20V/V and fast large-signal slew rates of 2V/µs. These capabilities allow them to detect rapid changes in the sensed current and quickly slew the output for applications that need a quick response to input current changes.

The launch of the series strengthens the company's 26V power rail current monitoring portfolio. It complements the previously released ZXCT199Q and the ZXCT21xQ series, which support highly precise high- and low-side current sensing across sense voltages down to 10mV.

All versions of the ZXCT18xQ series are specified for an operating temperature range of -40C to +125C.