topic Re: Reset max voltage when there is no supply in LPC Microcontrollers

Reset max voltage when there is no supply

n_boucquey — Thu, 10 Jan 2019 08:27:41 GMT

Hi,

We are trying to figure out if we can apply 5 V on the reset pin of the LPC1837JET100 even if its supply voltage is 0 V.

For other 5 V tolerant pins, the datasheet details that the max voltage is 3.6 V when there is no supply. Is it the same for the reset pin?

Many thanks in advance,

Nicolas Boucquey

Re: Reset max voltage when there is no supply

ZhangJennie — Fri, 11 Jan 2019 09:12:46 GMT

Hi Nicolas Boucquey,

The power supply for IO pin and reset pin are different. There are diodes connects with VBAT which protect VBAT. Thus we don't need worry voltage on reset go to VBAT. We only need consider reset pin pad itself -- 5V tolerant is ok.

While for IO pins, there is no such diodes exist. So we define 3.6V tolerant if VDDIO doesn't exist.

Have a great day,
Jun Zhang

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Re: Reset max voltage when there is no supply

n_boucquey — Fri, 18 Jan 2019 06:48:26 GMT

Many thanks Jun Zhang.

Have a great day too.

Best regards,

Nicolas Boucquey

Re: Reset max voltage when there is no supply

ZhangJennie — Fri, 18 Jan 2019 11:28:14 GMT

You are welcome!