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W5100 reset pin tolerance; is it 5 volt?

dear all,
my ethernet hardware based on W5100 is not working. I have suspicions regarding soldering issues.
However I have one more concern which I would like to ask you…
I power all W5100 pins with 3.3 volt. ONLY reset pin is managed with 5volt source.
Can you please inform me if RESET PIN can manage 5volt or not?
Acc. to datasheet there is no information regarding reset pin voltage tolerance.

best regards,


W5100 Reset Voltage is 3.3V

basically W5100 module is using LDO Regulator.

So, 5V input volt and Low drop 3.3V.

W5100chip operate 3.3Voltage.

don’t using 5Volt.

Thank you

Hi Edward, thank you for the reply.

Do you think did i damage the w5100 component?


Looking into datasheet section 7 “absolute maximum ratings” it says that Vin is 5V-tolerant. It does not exclude RESET from the signal list thus we may assume if you DO NOT hang reset input directly to +5V source (thus creating “unlimited” current) and use resistor or any other logic between +5V and RESET pin you should not damage pin. However you did a good observation - datasheet is not clear about control signals (see page 5, “3.3V operation with 5V I/O signal tolerance” - it says I/O signals).

Anyway, let’s assume that your chip is alive. How your device “does not work” - which symptoms you observe? Did you check supply voltage to be +3V3? Did you check its regulator output to be 1V8? Are you sure you use correct circuit design?

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