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LMK00334-Q1: Recommended CLKin Termination for LP-HCSL PCIe Gen 5

Part Number: LMK00334-Q1

Hi Team,

Can you please share the recommended LMK00334-Q1 CLKin termination components for a LP-HCSL PCIe Gen5 input clock?



  • Hello Antonio,

    LP-HCSL is a source terminated driver.  So typically the driver will need series resistance at the source in both the inverting and non-inverting output to absorb the reflection from the load.  The resistance at the source will depend if you are doing an 85-ohm or 100-ohm system but will generally result in a sum of 85 ohms / 2 or 100-ohms / 2.  The actual resistance may vary based on the specs of the LP-HCSL driver.  For instance, some drivers may have the source termination integrated.


  • Thanks, Timothy! For the LMK00334-Q1 HCSL outputs, if the differential trace impedance is 85ohm on the receiver side, should the termination resistors still be 50-ohm? I would assume so since it is a current-based topology but just want to confirm if it would be an issue with reflection from the load.


  • Hi Antonio,

    In the case of 85 ohm differential impedance, the 50 ohms to ground termination is still required and the Rs would be 27 ohms.