ZHCSHU2B March 2018 – October 2018 TPS7A10
PRODUCTION DATA.
The active discharge option (P version only) have internal pulldown MOSFET that connects a 120-Ω resistor to ground when the device is disabled in order to actively discharge the output voltage. The active discharge circuit is activated by driving the enable pin to logic low to disable the device, or when the device is in thermal shutdown.
The discharge time after disabling the device depends on the output capacitance (COUT) and the load resistance (RL) in parallel with the 120-Ω pulldown resistor. Equation 1 calculates the discharge time constant:
Do not rely on the active discharge circuit for discharging a large amount of output capacitance after the input supply collapses because reverse current can possibly flow from the output to the input. This reverse current flow can cause damage to the device. Limit reverse current to no more than 5% of the device-rated current.