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Thread: Teensy 3.5 5v output

  1. #1
    Junior Member
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    Teensy 3.5 5v output

    Hello,

    I am fairly new to using the teensy microcontroller. I am currently using the teensy 3.5, I was just wondering if I needed 5v output from the microcontroller to give power to a sensor which pin would I use? Arduinos have a 5v pin which you could connect to but I don't see the same with the teensy 3.5

  2. #2
    Senior Member PaulStoffregen's Avatar
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    None of the I/O pins have 5V output. They're all 3.3V out.

    You'd need to use a buffer chip like 74HCT245 or 74AHCT125 to convert the 3.3V signal to 5V. If you need a true 5V output, these buffer chips are the best way.

    There is also a popular mosfet transistor "bidirectional level shifter" circuit. It can be used in some applications, but the logic high output is weak (only due to a 10K resistor). The low-to-high transition is low. The high-to-low case is fast, and sometimes that's fine, but for other uses the huge difference in speed between the 2 changes can create problems. Some website sell that small circuit with big promises that it can be used as a drop-in solution whenever you need to convert levels - without much mention of the weak output and slow rise time. Buyer beware.

  3. #3
    Senior Member+ defragster's Avatar
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    Looking here - or on the card you may have gotten with the T_3.5 :: pjrc.com/teensy/pinout.html

    You'll see the pin labelled Vin - if powered from USB that pin will be at 5 volts from the USB connector.

  4. #4
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    What I am powering the teensy with an external power source and not through usb?

  5. #5
    Senior Member+ defragster's Avatar
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    Quote Originally Posted by tanzimm View Post
    What I am powering the teensy with an external power source and not through usb?
    Then that is going into Vin - and there is no source other than that and the 3.3V the Teensy generates from Vin. Another 5V supply wound be needed if the external source doesn't supply that.

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