TUSB8041: External Oscillator Input Requirement

Darren

The clock cell is a 1.8V cell.  The max range of the XI pin is listed as below, so you can not drive a 3.3V CLK signal into it. 

But why not use a 1.8V clock oscillator or a crystal in this case?

Thanks

David

Hi David,

We want to avoid generating a 1.8V supply as no other parts need it.
So we're looking at alternatives.

I will confirm with the clock team regarding voltage dividing down a clock;
but if you have any other comments I'm open to suggestions.

Regards,
Darre

Darren

Why not using a crystal oscillator if they don't want to have the 1.8V supply?

Thanks

David

Hi David,

They avoid crystals due to reliability concerns in solderability / drift / frequency variation / etc.
Not sure on all the background; but they rarely register a crystal.

Apart from the crystal or 1.8V CMOS clock; any other thoughts...?

Regards,
Darren

Darren

If they have to use a 3.3V clock, then I would use a level shifter to shift the clock from 3.3V down to 1.8V.

Thanks

David