DM8148 ref clock termination

Jean-Michel CAPITAN

Hi,

The DM814x processors have a differential input for the 100MHz SERDES reference clock.

This clock has to be 100R AC terminated.

Is this termination present in the DM814x chpi, or must we add an external 100R resistor close to the chip ?

0 Jean-Michel CAPITAN over 13 years ago

Can anybody from TI answer this question please ?

Thanks in advance.

0 AnBer over 13 years ago in reply to Jean-Michel CAPITAN

Will double check how the SERDES_CLKN and SERDES_CLKP need to be layed out.

It seems that on both PCBs (DM8148 EVM from Mistral - see page 25 and DM8168 EVM from Spectrum Digital - see page 12) there is provision for an 100ohm resistor but it is not installed:
http://www.mistralsolutions.com/pes-products/development-platforms/tmdxevm8148.html
http://support.spectrumdigital.com/boards/evm816x/revg/

I will try to clarify what should be done.

Anthony

0 Larry Taylor over 13 years ago in reply to Jean-Michel CAPITAN

External 100-ohm termination is not requried. This is handled internally.

Processors forum