Are the A/D pins on the K70 MCU 5V tolerant?

[ahuq]

The VDD on my MK70 CPU is at 3.3V and I am using using some of my GPIO pins as A/D . I have several op amps that are tied to my A/D pins for reading the voltages. My max voltage from op amp is 5V and I would like to know if my A/D on my MK CPU is 5V tolerrant.

[cutworth]

Hi,

You can refer the voltage and current rating spec in K70 DS.

The digital I/Os are 5V tolerant, this also includes the GPIOs with AD functions. For analog only pins, it's not 5V tolerant.

But for your question, you want to know if ADC is 5V tolerant or just the AD pins. Even the GPIO pins are 5V tolerant, when you input a voltage over VREFH of ADC, it will convert to 0xFFFF for 16bit mode. Is this meaning in your application? You do not want to add resistor divider for ADC inputs?

Hao

[kerryzhou]

Hi Al-hamra Huq,

      Please refer to the K70 datasheet:

   You can see, the ADC input voltage can't exceed 31*/32 VREFH when in 16bit differential mode, and all the other modes, the ADC input voltage can't exceed VREFH.

   The max Value of VREFH is VDDA, it is 3.6V.

   So, the ADC input pin is not the 5V tolerant pin, please take care!

Wish it helps you!

If you still have question, please let me know!

Have a great day,
Jingjing

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