AM2634-Q1: Please help check the customer crystal parameter

Will Gao

Intellectual 2335 points

Part Number: AM2634-Q1

Hi experts,

Customer chooses a crystal with following parameter information:

Rated frequency is 25MHz;

Rated loading capacitance (shunt capacitance) is 8pF;

The frequency resolution under room temperature is +- 20 ppm and +-50ppm @ -40~125C

ESR is 150Ω.

From the datasheet, we have the following parameters strictures:

It seems like that the ESR and shunt capacitance are over the maximum limitation? I am not sure, so please help check it.

Regards,

Will

over 3 years ago

+1 Randy Rosales over 3 years ago

TI__Mastermind 18500 points

Hi Will,

A few things here:

1. Yes, the crystal ESR needs to stay below the 46 ohms indicated in the datasheet table

2. CC1 and CC2 are the additional capacitors to be added to the crystal circuit. They should be less than 2x the crystal specified load capacitance, CL. CC1 and CC2 should be between 12pF and 24pF for the AM263x MCU oscillator circuit to function.

Please see the attached note for additional context here. I believe we will be adding similar supplementary information to the AM2x datasheets at a later time.

Thank you,

-Randy

AM263x_Crystal_Selection_rev1.pdf

0 Will Gao over 3 years ago in reply to Randy Rosales

TI__Intellectual 2335 points

Thanks for your reply, Randy. It is really helpful.

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AM2634-Q1: Please help check the customer crystal parameter