MAX14920/21 AFEs

Analog Devices' MAX14920/MAX14921 battery-measurement analog front-end devices accurately sample cell voltages and provide level shifting for primary/secondary battery packs up to 16 cells/65 V (max). The MAX14920 monitors up to 12 cells, while the MAX14921 monitors up to 16 cells. Both devices simultaneously sample all cell voltages, allowing accurate state-of-charge and source-resistance determination. All cell voltages are level-shifted to ground reference with unity gain, simplifying external ADC data conversion.

The devices have a low-noise, low-offset amplifier that buffers differential voltages of up to 5 V, allowing monitoring of all common lithium-ion (Li+) cell technologies. The resulting cell voltage error is ±0.5 mV. The devices’ high accuracy make them ideal for monitoring cell chemistries with very flat discharge curves, such as lithium-metal phosphate. External FET drivers support passive-cell balancing.

Integrated diagnostics in the devices allow open-wire detection and undervoltage/overvoltage alarms. The devices are controlled by a daisy-chainable SPI interface. The MAX14920 is available in a 64-pin (10 mm x 10 mm) TQFP package with an exposed pad. The MAX14921 is available in an 80-pin (12 mm x 12 mm) TQFP package. Both devices are specified over the -40°C to 85°C extended temperature range.