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Thread: Teensy 3.1 powering other devices

  1. #1
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    Teensy 3.1 powering other devices

    I was wondering if the Teensy is able to power two different devices through its 3.3 V pin.

    The two devices are an amplifier (https://www.adafruit.com/products/1712) and a radio (http://www.hoperf.com/rf/fsk_module/RFM69W.htm).

    After looking at the datasheets, the max current through a single pin on the Teensy is 25 mA, the amplifier's current draw is 3.5 mA, and the radio's current draw is 6 mA.

    According to these specs, I believe the Teensy should be able to power both devices, but I am unsure.

  2. #2
    Senior Member PaulStoffregen's Avatar
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    I'm confused. Are you talking about powering those devices from the 3.3V power pin (good for approx 100 mA), or powering them from digital pins in output mode (good for approx 10 mA)?

  3. #3
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    The 3.3V power pin.

  4. #4
    Senior Member PaulStoffregen's Avatar
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    Sure, it should work fine, because those 2 add up to much less than 100 mA.

    If it doesn't work fine (if you try to use a lot more than 100 mA), you'll be able to tell because the chip will get hot, and if you check with a voltmeter, you'll see the voltage much lower than 3.3V.

  5. #5
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    Thank you for your help.

  6. #6
    Senior Member+ defragster's Avatar
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    Quote Originally Posted by PaulStoffregen View Post
    If it doesn't work fine (if you try to use a lot more than 100 mA), you'll be able to tell because the chip will get hot, and if you check with a voltmeter, you'll see the voltage much lower than 3.3V.
    Paul: this is a helpful note I've not seen before - would be Wiki Worthy for diagnosing hot chips and also knowing when to look for 3.3v and why - Dropped a post #4 link in my Wiki ToBe thread. You probably have more similar notes I've note seen - or more to add on the topic. Like maybe if 5v VCC gets low or other common issues?

    Added here to Wiki Reminders
    Last edited by defragster; 07-22-2015 at 06:48 AM.

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