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Thread: External Power for the Teensy 3.6

  1. #1
    Junior Member
    Join Date
    Oct 2019
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    External Power for the Teensy 3.6

    Hi,
    I am attempting to power the Teensy 3.6 with an external 5V regulated power supply to the Vin pin. The 5V regulator is driven by a 12V supply (needed for other circuitry around the Teensy).

    Questions I have is as follows:

    1. Is the LM7805 regulator expected to get extremely hot? Is there anyway to reduce this?

    2. Should I be used the Analog GND Pin as Ground or the GND pin? Does it make a difference?

    Thanks in advance.

    /micupre

  2. #2
    Senior Member PaulStoffregen's Avatar
    Join Date
    Nov 2012
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    21,303
    Yes, linear regulators get hot. Use a heatsink, or a switching regulator.

    Use the normal ground pin.

  3. #3
    Senior Member
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    Nov 2015
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    Well if I make a guess the Teensy is drawing 300mA then the 7805 is dissipating (12-5) * 0.3 = 2.1watts. You didn't say anything about tthe package style of the regulator. If the regulator is in a 3-lead TO-220 package, then bolting it to a metal plate about 3 x 2 inches would lower its temperature. The 7805 may also be oscillating if there are no decoupling capacitors close by the leads on the inputs and outputs. You could also invest in a switching regulator. They do run cooler. I use these for my 5v project supplies.

    Use the GND pin as a supply ground. The Analog ground is there to keep the noise out of the analog system, especially when using the Teensy for sound/audio.

  4. #4
    Junior Member
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    Oct 2019
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    Thanks for all the information, I've ordered a switching regulator (thanks for the tip) last week. This should be in today, will wire that up and see how it goes.

    Kind regards,

    /micupre

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