AM6411: 50 Ohm termination on PCIE refclk pin would affect biasing voltage?

Frank(EP) Liu

Part Number: AM6411

Tool/software:

Hi Expert,

my customer has question below. Can you help me answer it?

TI SoC has 2x 50R termination resistors to GND for SERDES_REFCLK0_P/N (same as reference design). Please confirm with TI FAE that populating R30228 and R30234 does not alter biasing voltage of ref clock interface either when PCIe REFCLK is in Re-biasing Mode or it is in No Re-biasing Mode.

BR,

frank

over 1 year ago

0 Frank(EP) Liu over 1 year ago

TI__Expert 5190 points

Hi Expert,

any update?

BR,

frank

0 Frank(EP) Liu over 1 year ago in reply to Frank(EP) Liu

TI__Expert 5190 points

hi,

any update?

BR,

frank

0 -DK- over 1 year ago

TI__Mastermind 27890 points

This board was designed to support multiple interfaces and clock-sources so the "biasing" vs "no-biasing" note isn't applicable to the GPEVM in its current state. The need for the 49.9 Ohm resistors depends on on the clock source you choose for your design. In the case of the GPEVM, they are required to produce a HCSL compliant signal.

More details can be found here: e2e.ti.com/.../am6442-am64-pcie-refclk

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AM6411: 50 Ohm termination on PCIE refclk pin would affect biasing voltage?