LMK00804B-Q1: TCXO CMOS CLK as input to CLK Buffer LVCMOS_CLK input pin

Ravi Vijayaraghavan

Part Number: LMK00804B-Q1
Other Parts Discussed in Thread: LMK00804B

Hi,

We have TCXO CLK generator whose output is HCMOS and the output swing having VOL max of 0.1xVDD and VIHmin of 0.9xVDD. The VDD is 3.3V for both TCXO and LMK00804B.

We intend to drive the LVCMOS output of TCXO to LVCMOS_CLK input pin of LMK00804B.

Is there a concern as we do see that the recommended LVCMOS input level of LMK00804B has VIHmin of 2V and VILMax of 1.3V and the swing of TCXO is within the range?

Earlier the same approach was followed while using CDCLVC11XX IC instead of LMK00804B and it worked fine.

Pls clarify.

Thanks,

Ravi

over 3 years ago

0 Noel Fung over 3 years ago

TI__Guru** 109650 points

Hi Ravi,

output of the TCXO matches with the input clock requirement of the LMK device, it will work.

+1 Ravi Vijayaraghavan over 3 years ago

Prodigy 20 points

Hi,

Further to the response provided can you give some insight into the nature of the LVCMOS_CLK input pins of CDCLVC11xx and LMK00804B. I understand the latter has a 51K pull down.

Any other differences that is relevant to the nature the buffer drives a TCXO CMOS CLK output?

Regards,

Ravi

Clock & timing

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LMK00804B-Q1: TCXO CMOS CLK as input to CLK Buffer LVCMOS_CLK input pin