nRF52840 5V Tolerant GPIO

[masteffen]

Hi 

Is the GPIO on the nRF62840 5V tolerant?

I see the VDD supply is capable of 5.5V. 

I’m running a 5V Hall effect square wave into the GPIO pin used as an interrupt. 

I'm in pre-production and really need this to work.  If this will damage the input port, is there anything I can do to minimize the damage?  Limit current into the port? 

If there is an adverse effect, what will it be?  Port failure? Heating?  Or complete part failure?

It appears there are internal clamping Shottkey diodes on the GPIO inputs because the voltage is being clamped at 3.85V  

The port will only see this 5V square wave about 15% of the 10 year product life.  Otherwise the port will see 0V.

Please let me know.  

Mike Steffen

Bright Creations LLC

[Marjeris Romero]

And exposure to absolute maximum ratings for prolonged periods of time will affect the reliability of the device, so it's not recommended to have 3.9V over time.

The recommended conditions for GPIO input voltage when in high mode is VDD value. There are two domains on the supply, you have the VDD and VDDH domain. The maximum recommended operating conditions for VDD supply voltage are 3.6V. Only VDDH supports 5.5V, but GPIO supply runs from VDD domain, not VDDH.

See GPIO electrical specification: https://infocenter.nordicsemi.com/index.jsp?topic=%2Fps_nrf52840%2Fgpio.html&cp=4_0_0_5_8_2&anchor=unique_637624999

And recommended operating conditions: https://infocenter.nordicsemi.com/topic/ps_nrf52840/recommended_op_conditions.html?cp=4_0_0_7

I'm in pre-production and really need this to work.  If this will damage the input port, is there anything I can do to minimize the damage?  Limit current into the port? 

You need to adjust down the input voltage on the GPIO pins. If you go over the absolute maximum ratings over time you will brick the device.

Best regards,

Marjeris