TPS548A28: Max Crossover Frequency

Michael Balourdas

Part Number: TPS548A28

Hello,

My customer is working on a design with TPS548A28 and dealing with some compensation issues. They are planning to adjust the Cff but worried about crossover frequency. Based on this document, it looks like the crossover frequency just needs to be below 1/3 of Fsw. Am I interpreting that correctly?

https://www.ti.com/lit/an/slvaf11/slvaf11.pdf?ts=1670028576078&ref_url=https%253A%252F%252Fwww.google.com%252F

Thanks,

Michael

over 2 years ago

0 Ryan Chen over 2 years ago

TI__Genius 14827 points

Hi Michael,

Yes, it is best to have the crossover frequency to be below 1/3 of FSW. Equation 11 and 15 in the document are the max and min output capacitance for stability.
Adjusting the Cff improves the load transient response, increases the loop bandwidth and stability.

This application note better explains the selection of Cff and determining the crossover frequency.

Optimizing Transient Response of Internally Compensated DC-DC Converters (Rev. B)

Best,

Ryan

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TPS548A28: Max Crossover Frequency