Hi,
I am going to use a 3.3V CMOS single-ended input as clock input for LMK1D1204.
How should I configure the input circuit? I've found a similar reference design for the 3.3V CMOS single-ended clock input.
Can I use the recommended application setting for single-ended input signals?
Thanks,
Hello,
you cannot AC couple an 3.3V LVCMOS signal into LMK1D1204. See the datasheet recommendation below:
Vth can be set with resistor divider.
Regards,
Julian
Thank you for your reply.
I can't find the electrical characteristics of VIH and VIL for single-ended LVCMOS clock input in the datasheet. Only the highlighted part can be checked as shown in the table below.
Can I calculate Vth using VDD as VIH and 0V as VIL?
And can I leave the unused Vac-ref pin floating?
Thanks
Hello,
the requirement for the input swing is stated as VIN_S-E.
You'll need to check the actual input signal and take the VIH and VIL levels from that signal.
See section 9.2.1 for further details:
If V_AC_REF is not used you can leave it floating.
regards,
Julian
