LPC54xxx GPIO is powered earlier than VDD

[hiwave]

Hi, 

Customer is using LPC54016,  one IO pin is used to monitor the power supply state, which will be powered 160us earlier  than LPC54016 VDD,  can this result MCU power up failure?  or  is it potential risk? 

Does LPC54xxx have some limitations for power on? 

Thanks!    

Best Regards

Derek 

[xiangjun_rong]

Hi, Derek,

As you know that the digital pin has ESD protection circuit, if you can limit the current of the I/O pin to 2mA even if the VDD is not powered, it is okay. In other words, it is okay if you connect a serial resistor to limit the current to less than 2mA.

Hope it can help you

BR

XiangJun Rong