ISOW7841: Improve EMI emissions noise

Shuji Ishiwata

Part Number: ISOW7841
Other Parts Discussed in Thread: UCC33410, ISO7741, ISOW7741

Tool/software:

Hi All,

I have a question about the ISOW7841.
I would like to improve EMI emissions noise.
Are there any other solutions besides improving the board layout?

I am also considering using the UCC33410 and ISO7741 in a similar way to the ISOW7841.
Will the UCC33410 and ISO7741 generate the same amount of EMI emissions noise as the ISOW7841?

Best Regards,
Ishiwata

2 months ago

0 Koteshwar Rao 2 months ago

TI__Guru 54715 points

Hi Ishiwata-san,

Thank you for reaching out.

Do you know if customer has already made PCBs using ISOW7841 and tested for radiated emissions? If yes, then I would like to review the design and emissions test results before I make any suggestions.

If this is for a new design, then I recommend considering our second-generation device ISOW7741 which offers significantly higher overall performance and meets radiated emissions using a simple design.

Both UCC33410 and ISOW devices integrate isolated DC-DC converter in a small package and switch at high frequency. Due to this, it is important to follow the design and PCB layout guidelines to meet radiated emissions requirements. Thanks.

Regards,
Koteshwar Rao

0 Shuji Ishiwata 2 months ago in reply to Koteshwar Rao

Mastermind 6675 points

Hi Koteshwar-san,

Thanks for your reply.

EMI test results have been requested for the customer.
Please wait.

Best Regards,
Ishiwata

0 Shuji Ishiwata 2 months ago in reply to Shuji Ishiwata

Mastermind 6675 points

Hi Koteshwar-san,

I have received the ISOW7841 EMI test results.
I received the EMI test results from the customer, so I will send it to you via private message.
Can I send you a friend request?

Also, the E2E below states that adding chokes can improve the situation.
e2e.ti.com/.../3108951

Where should I place the chokes to be effective?

Best Regards,
Ishiwata

+1 Koteshwar Rao 2 months ago in reply to Shuji Ishiwata

TI__Guru 54715 points

Hi Ishiwata-san,

Yes, I have sent you a friend request. You can accept the request and send me the EMI test results. Please also send me customer schematic to review for any issues.

Yes, using common-mode chokes (CMC) at the input and output power supply pins of ISOW7841 can filter the radiation noise and keep the emissions to minimal. Please take a look at the below E2E post for more details related to CMC suggestion. Thanks.

https://e2e.ti.com/support/isolation-group/isolation/f/isolation-forum/806938/isow7841evm-isow7841evm

Regards,
Koteshwar Rao

0 Shuji Ishiwata 2 months ago in reply to Koteshwar Rao

Mastermind 6675 points

Hi Koteshwar-san,

I really appreciate your support in the private message.

Best Regards,
Ishiwata

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ISOW7841: Improve EMI emissions noise