ANALOGUE FRONT END DEVICE TQFP-64
The 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/+65V (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 +5V, allowing moni- toring of all common lithium-ion (Li+) cell technologies. The resulting cell voltage error is Q0.5mV. The devices’ high accuracy make them ideal for monitoring cell chemistries with very flat discharge curves, such as lithium-metal phosphate. Passive-cell balancing is supported by external FET drivers. 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 (10mm x 10mm) TQFP package with an exposed pad. The MAX14921 is available in an 80-pin (12mm x 12mm) TQFP package. Both devices are specified over the -40°C to +85°C extended temperature range.