About the Note of 8.1 Power sequencing

[keisukewatanabe]

According to datasheet, There is listed that is "At power down, it should be checked that 1.2V falls before 3.3V.".

Does Vybrid have this function? Should my customer do it?

Document Number: VYBRIDRSERIESEC Rev.5

[naoumgitnik]

Dear Keisuke,

Yes, Vybrid itself takes care of its 1.2V power rail, the only requirement being to NOT connect an external 1.2V source to it (i.e. following our datasheet and reference design).

Regards, Naoum Gitnik.

[keisukewatanabe]

I'm sorry, explanation is poor.

I want to know whether there is the way to drop 1.2V intentionally.

Best regards,

Keisuke Watanabe

[naoumgitnik]

Dear Keisuke,

Just an example of how the designer can violate this rule - if the capacitance on the 1.2V rail is too high (way higher than recommended in our documentation), then when powering down, the actual rail voltage might be decreasing so slowly that at some point would appear to be higher than that of the 3.3V rail one decreasing faster.

Regards, Naoum Gitnik.