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TPS62933: r4/c9 typical application question

Part Number: TPS62933

Hey team,

I was curious how to pick what resistance r4 in the datasheet is in the typical application? Do we have any resources on this topic besides simply suggesting <10 Ohms? Is it needed in a 5V-->1.05V application?

With regards to c9, I was curious if R6 = 53.6k, how much benefit with the feedforward capacitor provide with regards to phase margin & transient reduction?



  • Hi 

    Ruby will reply you next Monday!


  • Hi Cam

    Regarding the R4, it is used to reduce the rising rate of the switching node which can also reduce the ring of the switching node. This is benifit for EMI performance. But the ring of the switching node can be related the layout and the peripheral inductance and capacitance. We could recommend the initial value for your such as 10ohm, but the actual effect of this resistor should be evaluated according to different applications and layouts (by capturing the SW node waveform). If the EMI performance is rather important to your application, would suggest to add the resistor.

    With regard to C9, this also depends on the spec of your application. I would suggest to use Webench as a evaluation tool. You could set the spec and check the phase margin and cross frequency. If the cross frequency is high, it is benefit to the transient reduction.

    Hope this helps. Thanks.