The MAX14920/MAX14921ECS+ 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 MAX14921ECS+ 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 monitoring of all common lithium-ion (Li+) cell technologies. The resulting cell voltage error is ±0.5mV. 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 MAX14921ECS+ 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.
Feature
- High Accuracy
- ±0.5mV (max) Cell Voltage Error
- Simultaneous Cell Voltage Sampling
- Self-Calibration
- Integrated Diagnostics
- Open-Wire and Short Fault Detection
- Undervoltage/Overvoltage Warning
- Thermal Shutdown
- High Flexibility
- SPI Interface
- 12-Cell and 16-Cell Versions
- +6V Minimum (3 Cells) Operation
- +0.5V to +4.5V Cell Voltage Range
- Integrated Cell-Balancing FET Drivers
- Integrated 5V LDO
- Low Power
- 1μA Shutdown Mode
- 1μA/10μA Cell Current Draw
Applications
- e-Transportation Energy Packs
- Energy Storage Packs
- Industrial Battery Backup Systems
- Telecom Battery Backup Systems
