Sensor IC offers precision current measurement: “any material” shunts

November 03, 2014 // By Susan Nordyk
Using a 25-µΩ shunt – of almost any material – the SFP101 current, voltage, and temperature measurement IC from Sendyne typically achieves a current measurement accuracy to within ±0.05%, while operating over the automotive temperature range of –40°C to +125°C.

The device has a maximum voltage offset error of less than ±150 nV (±0.15 µV) for measurements of the voltage drop across a shunt. The AECQ100-qualified SFP101 provides user-definable automatic compensation for resistance dependence of the shunt from –40°C to +125°C. It is programmable to accommodate shunts with an output voltage ranging from ±10 mV to ±300 mV, which enables the device to work with a shunt of almost any resistance made from any material.

With an appropriate shunt, the SFP101 accurately measures a wide dynamic range of currents, from tens of thousands of amperes to milliamperes. The SFP101 provides onboard calibration for both current and voltage, storing calibration values and applying them internally. It also furnishes separate charge, discharge, and total Coulomb counters, and it measures four temperature points to within ±1°C.

Sendyne's SFP101EVB is an assembled circuit board that is outfitted with the SFP101 IC, support circuits for exercising all of the options and functions of the IC, and a permanently attached (mechanically, as well as electrically) 100-µΩ resistive shunt. The evaluation kit costs $183, including a serial-to-USB cable and control software.