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PSPICE-FOR-TI: TPS543C20 Pspice Transient simulation issues

Mark Guastaferro
Genius 11475 points
Part Number: PSPICE-FOR-TI
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.  

  • 0
    TI__Guru 54570 points

     

    Thank you very much for letting us know.  We will look into it.

  • 0
    TI__Genius 17905 points

    Hi Mark,

    Regarding 1), I verified the observation and have notified the modeling team to take a look into it. I will give an update by early next week on what I hear from them.

    Regarding 2), the API/BB functions are currently not modeled in the PSPICE model. Currently the best way to evaluate the API/BB functionality is on the EVM.

  • 0 in reply to Kris F
    TI__Genius 17905 points

    Hi Mark, I haven't heard back from the modeling team yet about 1). It could take some time depending on what is in their queue for fixes and new product model development. I hope the PGOOD issue is not gating you or your customer and that it was just something you noticed and wanted to bring to our attention.