TLK110 / unused pin

K.Yaita

Hi Team,

Could you tell me how to handle unused pin?
I would like to ask TX_CLK pin (1) and CLKOUT pin (25).

Best Regards,
Yaita / Japan disty

over 10 years ago

0 Ross Pimentel over 10 years ago

TI__Mastermind 23675 points

Hi Yaita-san,

The TX_CLK has an internal pull-down (weak). This could be left unconnected since there is a pull on it, however you could also add an external pull-down with a stronger value (2.2K ohm).

CLKOUT does not have internal pull-down or pull-up. It is recommended that if CLKOUT is not desired to tie it to ground for the shortest possible return to reduce any possible EMI.

Kind regards,
Ross

0 K.Yaita over 10 years ago in reply to Ross Pimentel

Guru 29720 points

Hi Ross-san,

Thank you for your quick reply!

It seems my customer saw CLKOUT pin(25) outputs about 1.55V.
Is it no ploblem to tie ground directly?
I would like to confirm just in case.

Best Regards,
Yaita

0 Ross Pimentel over 10 years ago in reply to K.Yaita

TI__Mastermind 23675 points

Hi Yaita-san,

It is recommended to use a pull-down resistor between the pin and ground . It is never recommended to tie CMOS drivers directly to either VDD or GND.

Kind regards,
Ross

0 K.Yaita over 10 years ago in reply to Ross Pimentel

Guru 29720 points

Hi Ross-san,

Thank you for your reply.
I understood.
Is there recommended value of pull-down resistor for CLKOUT?

Best Regards,
Yaita

0 Ross Pimentel over 10 years ago in reply to K.Yaita

TI__Mastermind 23675 points

Hi Yaita-san,

A 2.2K ohm resistor should be sufficient.

Kind regards,

Ross

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TLK110 / unused pin