TPS43061: FET Vds Rating

Evan Cornell

Part Number: TPS43061
Other Parts Discussed in Thread: CSD18503Q5A, CSD18514Q5A

Hello, I have implemented TPS43061 with VIN=12-15V, VOUT=24V, IOUT=5A (see https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=31B2E187EC33A8CB).

However, after building up some boards, I need to increase the output voltage as much as possible, but using the same FETs (High Side - CSD18514Q5A, Low Side - CSD18503Q5A).

What is TI's guidance on how much VDS margin is required in the Boost FETs? I can't seem to find any guidance either in the datasheet or in the Excel design tool.

Can I safely push the output voltage to 28-30V with just a feedback resistor change?

over 5 years ago

0 Garrett Roecker over 5 years ago

TI__Mastermind 21720 points

Hi Evan,

I would suggest giving about 10V or so of margin. So the 40V MOSFETs should be fine for this application when the output voltage is 30V.

-Garrett

0 Evan Cornell over 5 years ago in reply to Garrett Roecker

Expert 1380 points

Garrett,

Thanks for the feedback. Just as an FYI, Webench sort of flips out with FET selection for VOUT=25, 26, 27V etc., and doesn't suggest the 40V FETs I was using previously.

Thanks,
Evan

0 Garrett Roecker over 5 years ago in reply to Evan Cornell

TI__Mastermind 21720 points

Hi Evan,

Thanks for letting me know about WEBENCH. I'll look into it.

-Garrett

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TPS43061: FET Vds Rating