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DS90UB954-Q1: How to set CMLOUT

Part Number: DS90UB954-Q1

Hi team,

I will monitor the waveform through CMLOUT.

I have some questions about how to set enable to CMLOUT output.

#1

In the explanation of the datasheet CMLOUT pin there is a description of 100Ω termination, but the EVM had a coupling capacitor of 0.033uF.

Is a coupling capacitor necessary?

#2

Are there restrictions on the timing to enable CMLOUT output?

Best regards,

Tomoaki Yoshida

  • Yoshida-san,
    1. Yes for monitoring CMLOUT it should be terminated with a 100ohm differential. The EVM includes the AC coupling caps to keep the output DC bias. AC coupling is not necessary if you are using AC coupled probe or high impedance probe.
    2. The CMLOUT can be enabled at any time. Keep in mind the CMLOUT is only meant for identifying gross signal conditioning issues during debug and typically not used during normal operation.