The BQ76PL455ATPFCTQ1 is a 16-cell lithium battery pack monitor from Texas Instruments in TQFP-80, AEC-Q100 qualified for automotive applications. It monitors up to 16 series-connected battery cells with 14-bit ADC resolution, achieving +/-2mV cell voltage measurement accuracy across the full temperature range (-40C to +105C). The device uses a switched-capacitor ADC architecture: an internal multiplexer sequentially connects each cell input to the ADC through a capacitor, measuring the differential voltage between adjacent cell taps. Each cell measurement takes 200us, and all 16 cells are measured in 3.2ms. The device also supports passive cell balancing: each cell input has an internal FET that can discharge the cell through an external resistor (typically 100-200 ohms), allowing equalization of cell voltages. The UART communication interface supports daisy-chain topology: up to 32 BQ76PL455 devices can be connected in series (monitoring up to 512 cells) using a single host UART port, with each device acting as a repeater for downstream devices. The isolation barrier between the communication high side and low side provides 2500Vrms galvanic isolation between battery modules. The device includes comprehensive diagnostics: wire-break detection (open-wire), multiplexer self-check, ADC self-test, register parity, and communication CRC. The GPIO pins can measure external NTC thermistors for temperature monitoring. The internal regulators provide 5V and 3.3V for external circuitry, reducing BOM. The -TPFCTQ1 suffix specifies TQFP-80, AEC-Q100 grade 1, automotive.