LMK04610: Compatibility when Powering VDD_OSC supply rail with 1.8V and VCXO with 3.3V

DEEPAK V14

Part Number: LMK04610

Hi,

The LMK04610 is the major building block in our clock tree design. From the datasheet, I understood the following
1.OSCout will oscillate at start-up at the frequency of the VCXO attached to OSCin port and none of the other clock outputs is available.

The VCXO used here is CVHD-950-100.000 (From Crystek Corporation) and is powered by 3.3V.
But the VDD_OSC supply rail of LMK04610 is powered by 1.8V.

Q1. By keeping VDD_OSC at 1.8V and VCXO supply at 3.3V, what is the voltage level of LVCOMS clock available at OSCout pin during startup? Is it 3.3V LVCMOS or 1.8V LVCMOS?

Q2. Is it possible to operate VDD_OSC with 1.8V or else it has to be connected to 3.3V?

Thanks in advance
DEEPAK V

over 7 years ago

0 Puneet Sareen over 7 years ago

TI__Expert 8865 points

Hi Deepak
The LVCMOS levels at OSCout is 1.8V only in LVCMOS mode.
VDD_OSC supply range is 1.8V to 3.3V.
Best regards
Puneet

0 DEEPAK V14 over 7 years ago in reply to Puneet Sareen

Intellectual 810 points

Hi Puneet,

Thank you for replying within no time.
On the basis of your sugesstion I understood the following

Info1. Even if VDD_OSC is powered with 3.3V, LVCMOS clock at OSCout is only at 1.8V.
Info2. Even if VDD_OSC is powered with 3.3V or 1.8V, the OSCIN capable of accepting 3.3V LVCMOS clock from VCXO.

Please validate the above information I have understood.
Thanks once again for continuing support.

Thanks and regrds
DEEPAK V

0 Puneet Sareen over 7 years ago in reply to DEEPAK V14

TI__Expert 8865 points

Hello DEEPAK
Yes, this is correct.
Best regards
Puneet

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LMK04610: Compatibility when Powering VDD_OSC supply rail with 1.8V and VCXO with 3.3V