topic Capacitor for MMPF0100 VINREFDDR pin. in i.MX Processors

Capacitor for MMPF0100 VINREFDDR pin.

satoshishimoda — Tue, 25 Nov 2014 13:09:53 GMT

Hi community,

Our partner have a question about MMPF0100 connection.

Pelase see Table 4 of MMPF0100 datasheet (Rev.9.0).

It explains about VINREFDDR as following.

=====

VREFDDR regulator input. Bypass with at least 1.0 uF decoupling

capacitor as close to the pin as possible.

=====

However, in MCIMX6DQ-SDP schematics (SPF-27392_C3.pdf), the capacitance for VINREFDDR is less than 1.0 uF since two 0.1 uF capacitors are connected in series.

And 1.0 uF is connected to VREFDDR instead of VINREFDDR.

Which is correct?

Best Regards,

Satoshi Shimoda

Re: Capacitor for MMPF0100 VINREFDDR pin.

igorpadykov — Tue, 25 Nov 2014 15:41:36 GMT

Hi Satoshi

necessary capacitance is provided from DDR_1V5 side (connected to

VINREFDDR on SPF-27392 p.19). Also from MMPF0100 p.26 :

Table 20. VREFDDR External Components..

VREFDDR -- 1.0uF

footnote 30

VINREFDDR to GND, 1.0 uF minimum capacitance is provided by buck regulator output.

Best regards

igor

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Re: Capacitor for MMPF0100 VINREFDDR pin.

satoshishimoda — Wed, 26 Nov 2014 00:42:20 GMT

Hi igor,

Thank you for your reply.

OK, I understood the 1.0 uF to VREFDDR is OK.

And according to your reply, I understood the 1.0 uF capacitance written in footnote 30 is provided by C566, C571, C577, and C560 in SPF-27392.

Is this correct?

Best Regards,

Satoshi Shimoda

Re: Capacitor for MMPF0100 VINREFDDR pin.

igorpadykov — Wed, 26 Nov 2014 13:14:38 GMT

Hi Satoshi

yes, correct.

Best regards

igor