LMK00301: HCSL output

David Zhao

Part Number: LMK00301
Other Parts Discussed in Thread: XIO2001

My customer adopt LMK00301 to output REF CLK for XIO2001. Output format is HCSL, Current VPP is 1.6V, bigger than 1.2V max. If we adjust R320/R321 to 27ohm to get Vpp less than 1.2V, is LMK00301 ok for this change? Thanks!

Regards

David

over 8 years ago

0 Alan O over 8 years ago

TI__Mastermind 32575 points

Where are the 33R and 49R resistors placed in the layout? Are the series R's near the driver or load? Are the shunt R's near the driver or load? The shunt resistors should provide source or load termination for matching the PCB trace impedance. Is the trace impedance 85 ohm diff ,100 ohm diff, or other?

Regards,

Alan

0 David Zhao over 8 years ago in reply to Alan O

TI__Intellectual 1820 points

Hi Alan

39R and 49R are both placed near LMK00301. PCB trace is 100ohm difference impedance. After change 49R to 27R, the test waveform(test point is at XIO2001) is as below. Customer could accept this waveform. Then any risk for using 27R to replace 49R? Thanks!

Regards

David

0 Alan O over 8 years ago in reply to David Zhao

TI__Mastermind 32575 points

I see no issues with that. The signal integrity looks good.

Regards,
Alan

Clock & timing

Clock & timing forum

LMK00301: HCSL output