ZHCSMR2B December 2020 – December 2021 BQ76942
The REG1 and REG2 LDOs in the BQ76942 device are for customer use, and their output voltages can be programmed independently to 1.8 V, 2.5 V, 3.0 V, 3.3 V, or 5.0 V. The REG1 and REG2 LDOs and the REG0 preregulator are disabled by default in the BQ76942 device. While in SHUTDOWN mode, the REG1 and REG2 pins have ≈10-MΩ resistances to VSS, to discharge any output capacitance. While in other power modes, when REG1 and REG2 are powered down, they are pulled to VSS with an internal resistance of ≈2.5-kΩ. If pullup resistors for serial communications are connected to the REG1 voltage output, the REG1 voltage can be overdriven from an external voltage supply on the manufacturing line, to allow communications with the device. The BQ76942 device can then be programmed to enable REG0 and REG1 with the desired configuration, and this setting can be programmed into OTP memory. Thus, at each later power-up, the device will autonomously load the OTP settings and enable the LDO as configured, without requiring communications first.