SLUSF18A October 2023 – December 2023 BQ25638
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
BQ25638 uses the Narrow VDC architecture (NVDC) with BATFET separating the system from battery. The minimum system voltage is set by VSYSMIN register setting. Even with a fully depleted battery, the system is regulated to the minimum system voltage. If charging is enabled, the BATFET operates in linear mode (LDO mode). The default minimum system voltage at POR is 3.52V.
As the battery voltage rises above the minimum system voltage, the BATFET is turned fully on and the voltage difference between the system and battery is the RDSON of BATFET multiplied by the charging current. When battery charging is disabled and VBAT is above minimum system voltage setting, or charging is terminated, the system is regulated 50mV (typical) above battery voltage. The status register VSYS_STAT bit goes high when the system is in minimum system voltage regulation.