20-DSBGA package and I²C control
The BQ24156AYFFR is a single-cell Li-Ion/Polymer linear charger from Texas Instruments in a 20-DSBGA package (0.50 mm pitch, 0.35 mm ball diameter). The I²C interface handles charge current programming, timer settings, and status monitoring — no external resistors for current setpoint.
Charge parameters and protection
Maximum charge current is 1.55 A, programmable via I²C; the battery pack voltage ceiling is 4.44 V. Over-temperature and over-voltage fault protection are built in — the charger enters a safe state without external supervisory circuitry. Operating temperature range is -30°C to 85°C, covering most portable and industrial battery-powered equipment. Supply voltage max is 9 V, so a 5 V USB rail or a 9 V wall adapter both work.