JAJSQU2A August 2023 – October 2023 TPS25983
PRODUCTION DATA
PG is an active high open drain output which indicates whether the FET is fully turned ON and the output voltage has reached the maximum value. After power-up, PG is pulled low initially. The gate driver circuit starts charging the gate capacitance from the internal charge pump. When the FET gate voltage reaches (VIN + 3.6 V), PG is asserted after a de-glitch time (tPGD). During normal operation, if at any time VOUT falls below (VIN – VPGTHD), PG is de-asserted after a de-glitch time (tPGD).
1. When there is no supply to the device, the PG pin is expected to stay low. However, there is no active pull-down in this condition to drive this pin all the way down to 0 V. If the PG pin is pulled up to an independent supply which is present even if the TPS25983 is unpowered, there can be a small voltage seen on this pin depending on the pin sink current, which in turn is a function of the pull-up supply voltage and resistor. Minimize the sink current to keep this pin voltage low enough not to be detected as a logic HIGH by associated external circuits in this condition.
2. The PG pin provides a mechanism to detect a possible failed MOSFET condition during start-up. If the PG does not get asserted for an extended period of time after the device is powered up and enabled, this behavior can be an indication of internal MOSFET failure.