Maxim's Maxim MAX9934 high-precision, low-voltage, high-side current-sense amplifier is ideal for both bidirectional (charge/discharge) and unidirectional current measurements in battery-powered portable and laptop devices. Input offset voltage (VOS) is a low 10 µV (max) at +25°C across the -0.1 V to 5.5 V input common-mode voltage range, and is independent of V_CC. Its precision input specification allows the use of very small sense-voltages (typically ±10 mV full-scale) for minimally invasive current sensing.

The output of the MAX9934 is a current proportional to input VSENSE and is available in either 25 µA/mV or 5 µA/mV gain options (GM) with gain accuracy better than 0.25% (max) at +25°C. A chip select (CS) allows multiplexing of several MAX9934 current outputs to a single microcontroller ADC channel (see the Typical Operating Circuit). CS is compatible with 1.8 V and 3.3 V logic systems.