MAX9934 Current Sense Amplifier

By Maxim Integrated 193

MAX9934 Current Sense Amplifier

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 VCC. 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. 

  • -0.1 V to +5.5 V input common-mode voltage range
  • Chip select allows multiplexing several MAX9934 current monitors to one ADC
  • Current output allows ROUT selection for gain flexibility
  • Two gain options: GM of 25 µA/mV (MAX9934T) and 5 µA/mV (MAX9934F)
  • Input offset voltage: 10 µV (max)
  • Gain error less than 0.25%
  • Single supply operation: 2.5 V to 3.6 V
  • Bidirectional or unidirectional operation
  • Small, 6-bump UCSP (1 mm x 1.5 mm x 0.6 mm) and 8-pin µMAX packages