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Thread: Teensy 4.0 GPIO Output Current Limit?

  1. #1

    Teensy 4.0 GPIO Output Current Limit?

    Sorry if this should have been an easy question to research/answer on my own, but after much digging, I found nothing - what's the current limit for Teensy 4.0 output pins?

  2. #2
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    I don't know the answer to your question but my experience may be helpful.

    When supplying 6.41 mA to a load, the pin voltage(pin 22) dropped from 3.40 to 3.217 V, a drop of 183 mV.

    This suggests that 7 mA is getting close to the output current limit. But I don't know if my Teensy 4 is typical or not.

    Peter.

  3. #3
    Quote Originally Posted by PDOS View Post
    I don't know the answer to your question but my experience may be helpful.

    When supplying 6.41 mA to a load, the pin voltage(pin 22) dropped from 3.40 to 3.217 V, a drop of 183 mV.

    This suggests that 7 mA is getting close to the output current limit. But I don't know if my Teensy 4 is typical or not.

    Peter.
    Thanks Peter, I think I did see your post about that, and that seems reasonable given recent versions of the Teensies listed as 10mA.
    The reason I'm looking for this info for my current project is that I'm hoping to control some 12V automotive relays (via NPN transistors) and just want to make sure I don't ask for too much from the Teensy output pins. Using a 1k resistor in series from 3.3V to base, with a relay coil of ~80ohm at the collector, and emitter to ground, takes about 2.5mA from the base, so I should be okay with Teensy.
    And the other reason I ask is maybe also to make sure anyone else looking for this info can find it
    (I did skim the datasheet, and maybe output power is configurable for this microcontroller? I know SAMD21 can have a high and low power mode for output pins...)

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