topic Re: 8MHz Crystal for KV31 in Kinetis Microcontrollers

8MHz Crystal for KV31

shai_b — Mon, 29 Mar 2021 23:29:21 GMT

Dear team,

I need your advice on the selection of an 8MHz crystal for the KV31 MCU.

The EVK contains a resonator of 8MHz (PN: CSTCE8M00G55-R0) which this component got obsolete.

Could you please confirm that Hc49/SMD-BF30-30-8.000M-TR is suited/compatible for KV31 MCU (please find the spec below)

Spec: https://www.transko.com/img/product/crystal_pdf/hc49smd.pdf

Waiting for your kind response, Thanks in advance

Regards,

Shai

Re: 8MHz Crystal for KV31

myke_predko — Tue, 30 Mar 2021 00:40:05 GMT

@shai_b

Looks fine. I'm using the ECS-80-18-5PX-RR which has basically the same operating parameters.

myke

Re: 8MHz Crystal for KV31

jingpan — Tue, 30 Mar 2021 09:01:53 GMT

Hi,

You can refer to AN1706 and AN1783.

https://www.nxp.com/docs/en/application-note/AN1706.pdf

https://www.nxp.com/docs/en/application-note/AN1783.pdf

It is very hard to say "this crystal is OK to use with microcontroller XXX" as there are so many variables in the oscillator circuit. But for the customer, what is very important is that the oscillator starts up across the full operating range of their product (temperature and voltage). And that the crystal starts up on the correct frequency and not a harmonic or is de-tuned.
Please used application note AN1783 as reference. It is over 20 years old, but the information is very useful.

Regards,

Jing

Re: 8MHz Crystal for KV31

shai_b — Tue, 30 Mar 2021 09:38:31 GMT

Hello @myke_predko and @jingpan ,

Thank you so much for your inputs.

KR,

Shai