TPS542951: Schematic Review

Matthew Crocker

Part Number: TPS542951
Other Parts Discussed in Thread: TPS54291

Hello,

I was hoping to have the use of the TPS54291 in the linked schematic reviewed. I made use of the WeBench power designer for this particular part, the designs produced by WeBench and the example applications in the data sheet are different so I wanted a confirmation of the design. The TPS542951 should be producing a 3.3V output and a 5V output in this design.

Schematic Link

I appreciate your assistance with this matter.

over 2 years ago

0 Matthew Crocker over 2 years ago

Prodigy 100 points

Thought it would be good to add these as references.

5V Version from WebDesigner

3.3V Version from WebDesigner

0 Tahar Allag over 2 years ago in reply to Matthew Crocker

TI__Mastermind 29630 points

Hello Mattthew,

I am looking on your SCH. I will be sending my comments today.

thanks

Tahar

0 Tahar Allag over 2 years ago in reply to Tahar Allag

TI__Mastermind 29630 points

Hello Matthew,

Here are my comments with the assumption IOUT=2A and VIN=12V.

3.3VOUT, I recommend 2.2 to 3.3uH inductor with the right saturation currents rating.
for the 5VOUT, i recommend 4.7uH.
add CFF capacitor on the Feedback resistor , use 5 to 22pF
COUT looks good, just make sure the voltage rating is good
CIN, The capacitors voltage rating needs to be greater than the maximum input voltage.
5Vout, change R30 to 124K to get 5.0V.

use the user guide EVM as layout example to follow:

https://www.ti.com/lit/ug/slvu767/slvu767.pdf?ts=1633100826570&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FTPS542951EVM-057

thanks

Tahar

0 Matthew Crocker over 2 years ago in reply to Tahar Allag

Prodigy 100 points

Hello Tahar,

Thank you for your time and effort and the good advice, I made the recommended changes as you suggested, I just had a question about the CFF Cap, those would be in parallel with R15 and R30 as shown in the new schematic, correct?

New Schematic

+1 Tahar Allag over 2 years ago in reply to Matthew Crocker

TI__Mastermind 29630 points

Hi Matthew,

yes, you are correct

thanks

Tahar

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TPS542951: Schematic Review