LMK00304: Do you need far end termination for HCSL output

Kikuo Mita

Other Parts Discussed in Thread: LMK00304

Hi,

Please advise me on how to use HCSL output.
In order to get higher output amplitude than LVDS and smaller amplitude than LVPECL,
I want to use HCSL output of LMK00304.
The reference schematic does not show far end termination.
Don’t you need far end termination?

If not, how is the reflection controlled.
On receiver side, I will use non HCSL device such as LVDS like devices
(not fully compliant to LVDS specifications)

Mita

over 12 years ago

0 Alan O over 12 years ago

TI__Mastermind 32575 points

Hi Mita-san,

Far-end termination is not required when near-end termination is used with the HCSL driver. If near-end and far-end terminations (i.e. double termination) is used, it will effectively reduce the swing seen by the receiver by half. With near-end termination only, any reflected wave returned to the driver side will be absorbed by the near-end termination without a reflection.

Regards,

Alan

0 Kikuo Mita over 12 years ago in reply to Alan O

TI__Intellectual 2515 points

Alan-san,

thank you for the answer.

Mita

Clock & timing

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LMK00304: Do you need far end termination for HCSL output