AWR1642: What's the value of Cp in Figure 5-3. Crystal Implementation of datasheet

Chris Meng

Part Number: AWR1642

Hi,

In AWR1642 datasheet, we can find below info. Does the Cp mean the capacitance of the CLKP and CLKM pins? What's the value of Cp for AWR1642?

over 6 years ago

0 Vivek Dham over 6 years ago

TI__Guru 58035 points

Hello Chris,

Yes the Cp value corresponds to the total capacitance load between the XTAL pins. This includes the shunt cap on CLKP and CLKM pins of the XTAL and also PCB parasitic capacitance.

The required value of the Cp depends on the XTAL used, you will find the load cap mentioned in the datasheet of the cryal part.

Regards,
Vivek

0 Chris Meng over 6 years ago in reply to Vivek Dham

TI__Mastermind 37686 points

Vivek,

Yes, in Crystal datasheet, we can get the CL value.

I think we need to know the value of Cp to select the Cf1 and Cf2. So how to get the value of Cp? For Cp, does it related to the internal equivalent capacitance of XTAL interface of AWR1642? If yes, what the value of it?

0 Chris Meng over 6 years ago in reply to Chris Meng

TI__Mastermind 37686 points

Vivek.

Any comment?

0 Vivek Dham over 6 years ago in reply to Chris Meng

TI__Guru 58035 points

Hello Chris,

As mentioned above Cp depends primarily on the PCB trace/pad parasitic cap. So this will depend on the PCB layout.

regards,
vivek

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AWR1642: What's the value of Cp in Figure 5-3. Crystal Implementation of datasheet