26V current sensor in 2.9 x 2.8mm has 1% error

Rohm has announced a high-side current sensor with a -0.2 to +26V input common-mode range and ±1.0% maximum gain error.

Packaged in a 2.9 x 2.8 x 1.25mm SSOP6, BD14210G-LA senses voltage across an external high-side resistor and transfers this to a voltage relative to the 0V rail with a fixed gain of 20. Max offset is ±0.6mV (refered to the input).

Inside it is a two-stage design, with a chopping amplifier front end (switches missing from diagram) followed by a differential amplifier. With two stages, Rohm claims that the gain of the differential stage is not affected by adding an RRC input noise filter, with a pair of 10Ω resistors, for example.

The voltage at the output is with respect to a voltage supplied to its reference input (Electronics Weekly has asked how the external potentiometer in the diagram interacts with the internal resistors).

It needs its own 2.7 to 5.5V power supply, from which it typically draws 170μA, and it operates over -40 to +125°C. The ±1% worst case error is right across this temperature range, and over outputs between 500mV and Vdd-500mV.

This is the first of a family (see table) of high-side current sensing ICs with gains up to 200. There will also be dual versions in 3 x 4.9 x 1.1mm TSSOP-B8J packaging.

☆ in the pipeline

For development, there is the Refsens003 ±30A current sensing evaluation kit (pictured), that uses the company’s own LTR50UZPFU sensing resistor with the BD14210G-LA current sense amplifier.

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