KL27 max supply current and single pin current limit

[jh0]

Hi,

There is "Voltage and current absolute operating ratings" table inside device datasheet. And there are values from table, 120mA Idd (Digital supply current) and 25mA Id (Instantaneous maximum current single pin limit).

I want to know what will happen if current on single pin is going higher, or in case of short? Or if digital supply current going higher? Let say that for example device is working on 3.3V Vdd. There are some internal protection or device will be destroyed? I know that some pins are with high drive option (that can deliver 20mA, that is close to noted 25mA limit). What will happen in case of connecting together output of other pins (without high drive option) from the same port, let say in perfectly (one cycle) aligned switching?

Regards,

Josip

[kerryzhou]

Hi Josip Haluska,

     Please note the datasheet the following points:

Talk about your questions, the total current for all ports is 100mA in max, single pin driver ability won't higher than 25mA. So, if you want to output the current higher than 25mA in 1 pin, the MCU can't out it, it doesn't have the ability to driver it. The MCU won't be destroyed,  the pin won't output the current higher than 25mA.

Wish it helps you!

Kerry

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[jh0]

Hi Kerry,

I now all this datasheet tables, just need confirmation that device and port pin will not be damaged in the case of over 25mA or in case of port pin short circuit. What will happen with device if port pin is set to output high (3.3V) and it is shorted to ground? Or if it is shorted to ground over 10 ohm resistor?

Thank you,

Josip

[kerryzhou · Accepted solution]

Hi Josip Haluska,

    Today, I do a test in the KL43, which pin current limit is the same as your KL27.

    I test PTB0 output high 3.3V, then connect it to ground,  and test the current through PTB0 and the ground, the current is 37.8mA, but I just test it for a short time, then I check disconnect the ground, and test the PTB0 again, it still can output 3.3V, it means this pin is not damaged.

    So, if the pin is over 25mA in a short time, the pin won't be damaged, but if the time is long, the chip may hot, and the pin have the risky to be damaged(maybe short to ground).

    Anyway, we suggest you still follow the datasheet defined data, otherwise, the chip performance can't be guaranteed.

Wish it helps you!

Kerry

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