TPS54561: Output current trace width

Fedor Adarichev

Part Number: TPS54561

This part is supposed to be able to output up to 5A continuously, but the output SW pin only allows a trace that is 0.32mm thick, this is the thickness of the recommended pad size for the IC footprint. On 2 oz/ft^2 copper, with external trace layers exposed to air, 0.32mm only allows 1.7A. So, how is this device supposed to be able to output 5A?

over 7 years ago

0 Robert Blattner over 7 years ago

TI__Expert 6245 points

Hello Fedor,

Minimum trace width depends on trace length. I will get back to you with details.

Regards, Robert

0 Robert Blattner over 7 years ago in reply to Robert Blattner

TI__Expert 6245 points

Hello Fedor,

I have found where to look to verify that thinner traces can be used if limited in length. It is in IPC2152 under necking rules. The trace can be thinner if temperature rise is limited. For traces that are short for a limited distence, heat is conducted to the wider portions limiting temperature rise. If layout guidlines in the datasheet are followed, the connection that you describe is within spec.

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TPS54561: Output current trace width