TPS2543-Q1 - Are the 15k pull-down resistors required in the USB D+ and D- data lines?

Marcos Videla

Other Parts Discussed in Thread: TPS2543-Q1

Hi everyone,

We at Delphi E&S, Buenos Aires, Argentina, develop radio head units which use this IC mainly as a CDP emulator and needed to know if the usual 15k pull-down resistors in the D+ and D- data lines are still required (externally), or it is already provided by the IC? In case the resistors are needed, should these be connected on the DX_IN or DX_OUT side?

Thanks and best regards,

Marcos A. Videla

Electrical Engineering Group

Delphi E&S TCA - Buenos Aires - Argentina

over 9 years ago

0 Eric Wright over 9 years ago

TI__Mastermind 42795 points

TPS2543-Q1 can support BC1.2 CDP handshake with DP_IN/DM_IN without any external resistors. I am not aware of the usual 15k resistors and will have to check about when and why those might be needed.

0 Marcos Videla over 9 years ago in reply to Eric Wright

Prodigy 30 points

Hi Eric,

Thanks for your support.

I'm attaching a document which is part of the USB2.0 specification, it's about the pull-down and pull-up resistors of the bus.

If you think these are not necessary is ok, however if you can check and confirm that better.

Best regards,

5852.resistor_ecn.pdf

0 Eric Wright over 9 years ago in reply to Marcos Videla

TI__Mastermind 42795 points

Hi Marcos,

I have confirmed that the TPS2543-Q1 (charging controller) does not have the referenced pullup and pulldown resistors. This function is usually integrated into the USB hub or host conrtoller (internally).

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TPS2543-Q1 - Are the 15k pull-down resistors required in the USB D+ and D- data lines?