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TPS54561-Q1: Sw node maximum rating

Part Number: TPS54561-Q1
Other Parts Discussed in Thread: TPS54561

I am using TPS54561 for converting 50V to 5V.As specified in the datasheet,the Sw node voltage should not exceed -0.6V.But my switch node voltage is reaching nearly 900mV..Will it damage the device.

Catch diode:V8P10-E3/86A.

TPS54561 SW node.pdf

  • The -0.6V absmax spec on the SW node is a DC spec. I believe when you say your SW node voltage is -0.9V referring to ringing spikes at the falling edge of the SW waveform. It does not violent the DC spec. Also, the observed ringing magnitude may change with probing of the node. Make sure the ground loop of your probe is minimized. Layout of the board also affects ringing magnitude. Please double check your layout with datasheet layout recommendations.
  • I am getting the negative spike as -1.6V for 440ns while probing with the minimized ground loop too.Also the Sw node DC voltage i.e OFF time of Top switch,it is a steady dc voltage of -0.9V since my catch diode forward voltage is 0.582V @8A.I am loading it for 5V @100mA.Please refer the SW node image attached.TPS54561 SW node image.pdf