TUSB9261 Oscillator/Crystal input requirements

Hello Bill,

Both, the datsheet and the implementation guide are correct, although I agree that the implementation guide is a little bit confusing in the figure you talk about.

Let me explain, the 3.3-V label on the oscillator (on the Implementation Guide Figure 4) is the supply, but not the output, this is a generic block diagram just as example, if you go to the Schematics section you can see that XI is sourced with 1.8-V signal.

The reason for this is that the XI input cell type is only 1.8-V tolerant. The reasons for using this type of input cell I'm afraid is out of my bandwidth.

Regards.

Hi Elias,

Thanks for the reply.

Does that mean I really need an oscillator with VDD of +1.8VDC?

With a VDD 0f +3.3VDC as the implementation guide is showing on page 10, the oscillator output will be swinging from Vss up to near VDD.

Thanks,

--Bill

Yes, the clock input to XI must swing from Vdd (0 V) to 1.8-V.

Here are the specs:

Min: 1.62 V

Nom: 1.8 V

Max: 1.98 V

Regards.

Thanks Elias!

--Bill