topic Re: MMPF0100 RESETBMCU impedance. in i.MX Processors

MMPF0100 RESETBMCU impedance.

satoshishimoda — Mon, 18 May 2015 08:42:57 GMT

Hi community,

Our partner have a question about MMPF0100 specification.

To decide the pull-up resistor value, they want to know the impedance of RESETBMCU pin.

You know the voltage level is decided by voltage dividing between pull-up resistor and pin impedance.

For example, if RESETBMCPU impedance = 70k ohm, the pull-up resistor value should be up to 30k ohm for i.MX6.

Certainly, we know the pull-up resistor value on the SABRE board (10.0k ohm) is a solution, but the impedance is required to decide the pull-up value strictly for a custom board that RESETBCMU is connected to not only i.MX6 but also other chip.

Would you let me know it?

Best Regards,

Satoshi Shimoda

Re: MMPF0100 RESETBMCU impedance.

igorpadykov — Mon, 18 May 2015 12:29:45 GMT

Hi Satoshi

according to datasheet p.13

2mA/0.4V --> max.200 Ohm impedance

Best regards

igor

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Re: MMPF0100 RESETBMCU impedance.

satoshishimoda — Tue, 19 May 2015 00:19:52 GMT

Hi Igor,

Thank you for your reply.

OK, I understood the value when RESETBMCU is low.

Then, how about when RESETBMCU is high?

I think the impedance when it is high is huge value since the internal transistor is OFF, and maybe the impedance does not affect the external resistor value, but would you let me know to make sure?

Best Regards,

Satoshi Shimoda

Re: MMPF0100 RESETBMCU impedance.

igorpadykov — Tue, 19 May 2015 09:00:34 GMT

Hi Satoshi

when RESETBMCU is high (this is open drain output)

its impedance is big, though it is not specified by

datasheet, probably more Mohms.

Best regards

igor