TUSB320LAI: TPD2S300: CC Line Capacitor selection

Shmuel Davis

Expert 2920 points

Part Number: TUSB320LAI
Other Parts Discussed in Thread: TPD2S300

I need to calculate the CC Line Capacitor selection for the TPD2S300.

I posted the following :-

https://e2e.ti.com/support/interface/circuit-protection/f/389/t/651056

and thus I posted

https://e2e.ti.com/support/interface/usb/f/1008/t/651328

From these responses it is still going to be difficult for me to make the choice of the required capacitor (if any is required ?)

Does anyone have any suggestions ?

over 7 years ago

0 Luis Omar Moran over 7 years ago

TI__Genius 16150 points

Hi Shmuel,

For PD applications place a capacitor that meets the tDRP maximum = 1ms, hence you should select a value that the constant of time accomplish this timing requirement.

Regards,
Luis Omar Moran
High Speed Interface
SWAT Team

0 Shmuel Davis over 7 years ago in reply to Luis Omar Moran

Expert 2920 points

Dear Luis Omar Moran,

Thank you for your response. Please could you explain in more detail what you mean ?

Best regards

Shmuel

0 Luis Omar Moran over 7 years ago in reply to Shmuel Davis

TI__Genius 16150 points

Hi Shmuel,

According to the Type-C specification, in a power delivery application the capacitor placed in the CC line should meet the requirement of tDRP=1ms, I mean the constant of the time of such capacitor needs to achieve at least this parameter to work properly.

Regards,

Luis

0 Shmuel Davis over 6 years ago in reply to Luis Omar Moran

Expert 2920 points

Dear Luis Omar Moran,

1. Are you referring to the tDRP within the data sheets ? ("The period during which the TUSB320HA or the TUSB320LA in DFP mode completes a DFP to UFP and back advertisement") ? If YES : so can you please explain how this relates to the capacitor ? Also if yes I am implementing a UFP so is this even relevant. If no - then please could you outline what this "constant of time" of the capacitor what parameter is it related to and how is it measured \ defined

2. How does your response relate to my first question relating to the value of the capacitor in order to stay within the USB PD 3.0 specs that one will need a min. cap. of 200pF and a max cap. of 600pF on the CC channels ?

0 Luis Omar Moran over 6 years ago in reply to Shmuel Davis

TI__Genius 16150 points

This thread has been solved in this post:

e2e.ti.com/.../2418071

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TUSB320LAI: TPD2S300: CC Line Capacitor selection