LMH0356: Crystal does not oscillate with device

Maksim Oshchepkov

Part Number: LMH0356
Other Parts Discussed in Thread: LP5907

Hi to all!

I have some troubles with starting of LMH0356 27MHz clock generator.

I already checked circuit, 39pF capacitors, tried two different crystals - 7B-27.000MBBK-T, TXC and other in HC-49/S case.

In all attempts i have the same oscillograms:

Between XTAL IN and XTAL OUT

Beetwen GND and XTAL IN, XTAL OUT

Is there any ideas what else may be done to start oscillation?

Thank you.

0 Lee Sledjeski over 8 years ago

Hi Maksim,

Is the LMH0356 device powered on?

Have you tried to decrease the capacitor values to ~ 20pF to reduce the loading?

Regards,

Lee

0 Maksim Oshchepkov over 8 years ago in reply to Lee Sledjeski

Hi Lee,

Thank you for your attention!

Yes, LMH0356 powered on, by LP5907 LDO. Power is OK (on oscilloscope screen).

I tried 22 pF capacitors, but it did not help.

Now it works from SG-8002CA/PCB 27.000MHz oscillator, and it looks like the only decision.

0 Lee Sledjeski over 8 years ago in reply to Maksim Oshchepkov

Hi Maksim,

Thanks for your reply! I am glad you found an oscillator that can work in the application.

Regards,

Lee

Interface forum