TPS40170-Q1: Failed EMC test (CE voltage)

Jeffrey Chung1

Part Number: TPS40170-Q1

Hi TI Team,

The EMC test of CE voltage has been failed on my customer's board using TPS40170-Q1. Are there any points to resolve and improve this issue? Please check an attached file and let me know that.

TPS40170QRGYRQ1_Failed EMC test.pdf

Regards,

over 1 year ago

0 EricLee over 1 year ago

TI__Mastermind 49471 points

Hello Jeffrey

I guess you need a dramatic change to pass the CE test since 5Ω gate resistor is still not enough... Please consider these items.

Add input filter, especially add a bead. Also, populate the additional input capacitor in the range of 10nF to 100nF at the input terminal.
Optimize snubber.
Re-design PCB layout and make the switching loop as small as possible.
Use higher Qg, but lower Rdson MOSFETs.

- Eric Lee

0 Jeffrey Chung1 over 1 year ago in reply to EricLee

Expert 2705 points

Hi Eric,

I appreciate your kind suggestions. Let me check these points with my customer and I will let you know the improvement status or more questions.

Regards,

0 EricLee over 1 year ago in reply to Jeffrey Chung1

TI__Mastermind 49471 points

Hello Jeffrey

Also, the SW rising edge ringing can be reduced by populating a Schottky diode in parallel with the low-side MOSFET.

- Eric Lee

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TPS40170-Q1: Failed EMC test (CE voltage)