Other Parts Discussed in Thread: TPS543C20
While using the Pspice Transient model for the TPS543C20, I am seeing two issues that may be related. I used the reference design provided with Pspice for TI and changed the input voltage from 12V to 5V:
1. When running a start-up response, the PGOOD signal seems to be asserted for several msec as the device powers up and then gets pulled down before the output starts to ramp. PGOOD responds as expected when Vin = 12V.
2. If the start-up is run with the MODE pin pulled low through a 15.4k resistor to activate API, the output doesn't seem to start-up properly and the regulator shuts down after 1 ms. This happens with either Vin = 12V or Vin = 5V, but with Vin = 5V, the shutdown happens when the PGOOD goes low as seen in item1.
