TPS62745: Need schematic review

Abhi Choksi

Intellectual 500 points

Part Number: TPS62745

Our system Requirements

Vbat = 7.2V
Vout = 3.3V
Iout = 210mA
Require low EMI and High efficiency.

We have implemented buck converter circuit of TPS62745 using Figure 34 of datasheet.

Please review schematic and let us know any changes required.

Also we have some doubts as listed below.

Can we use 10uF-0402 capacitor instead of 10uF-0805?
Do we need to put 100nF-0402 capacitor in parellal with in/out capacitors for good EMI performance?

Please refer sheet 4 of attached schematic.PCB-CHTRKR-2138-1A-01.pdf

over 2 years ago

+1 Nancy Zhang over 2 years ago

TI__Mastermind 45900 points

Hi Abhi,

The schematic looks good. But for input/output ceramic capacitor, 10uF is the total effective capacitance. We recommend at least 0603 package in the datasheet table 6. You may use 10uF/0402 as long as the effective capacitance after applied 12Vin(after 12Vin derating) is higher than recommended value in datasheet section 7.3. You can put a 1000nF /0402 parallel with input/output cap to improve EMI performance.

Thanks,

Nancy

0 Nancy Zhang over 2 years ago

TI__Mastermind 45900 points

Hi Abhi,

Sorry, typo, 100nF to instead of 1000nF.

Thanks,

Nancy

0 Abhi Choksi over 2 years ago in reply to Nancy Zhang

Intellectual 500 points

Thanks nancy for review.

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TPS62745: Need schematic review