TMS320C6727: Recommended ferrite beads

Earl Landry

Part Number: TMS320C6727

The ferrite listed for use on the PLL pin TDK ACF451832-333 is not recommended for new designs. Is there another recommended alternative I can use? And what is the current draw of the PLL pin. I don't see it in the spec sheet.

Earl

over 6 years ago

0 Yordan Kovachev over 6 years ago

TI__Guru**** 161600 points

Hi Earl,

You can use the EMI filter from the reference design (which is TMDSDSK6713):
c6000.spectrumdigital.com/.../6713_dsk_schem.pdf

That is: EXCCET103U

Best Regards,
Yordan

0 Earl Landry over 6 years ago in reply to Yordan Kovachev

Prodigy 50 points

This filter shows obsolete at distribution. But it did lead me to an alternative, since there was a recommended equivalent on one of the websites. The replacement is a Panasonic ELKE333FA which has very similar characteristics to the original TDK part. Current rating is higher and package is different, but this will probably work with a quick PCB layout change.

0 Earl Landry over 6 years ago in reply to Earl Landry

Prodigy 50 points

One remaining question from the original post. Does anyone know if there a current (mA) spec for the PLL pin on the 6727 part? I don't see it in the TI specification sheets. It would be helpful in spec'ing the new EMI filter.

0 Yordan Kovachev over 6 years ago in reply to Earl Landry

TI__Guru**** 161600 points

Hi,

I am not sure if we have such specs. Let me confirm that with the hw designers.

Best Regards,
Yordan

0 Mark M over 6 years ago in reply to Yordan Kovachev

TI__Mastermind 29560 points

Hi Earl,

I am not finding any information for the current requirements of the PLLHV pin.

It is not specified in the C672x Power estimation spreadsheet: www.ti.com/.../spraaa4

I can only suggest you match the rating for the EMI filter that is discussed in the datasheet:
EMI Filter: TDK ACF451832−333, −223, −153, or −103, Panasonic EXCCET103U, or Equivalent.

Regards,
Mark

0 Earl Landry over 6 years ago in reply to Mark M

Prodigy 50 points

We are currently using 100mA T filters on the board in other places and I was trying determine if this would be sufficient for the PLL filtering. Trying avoid making a board change.

Earl

0 Earl Landry over 6 years ago in reply to Earl Landry

Prodigy 50 points

I measured the current being drawn by the PLL pin and it was 12.7 mA. So I am satisfied that it is safe to use my 100mA filter I mentioned above. I guess this issue is closed since I have all the information I need.

Earl

0 Mark M over 6 years ago in reply to Earl Landry

TI__Mastermind 29560 points

Hi Earl,

Thanks for sharing your solution with the forum.

Regards,
Mark

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TMS320C6727: Recommended ferrite beads