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Thread: Teensy Low Voltage Operation?

  1. #1
    Junior Member
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    Teensy Low Voltage Operation?

    The datasheets for the MKL26Z64VFT4 (Teensy LC processor) and the MK20DX256VLH7 (Teensy 3.1/3.2 processor) and also the MKL02Z32VFG4 (on the LC and 3.2) all list an operating voltage of 1.71 to 3.6 V. Does that mean that the Teensy LC and 3.2 could work with voltages down to 1.71V?

    The MINI54's datasheet (on the 3.0 and 3.1) lists a supply voltage range of 2.5 to 5.5V. Does that mean the 3.0 and 3.1 could operate with voltages down to 2.5V?

    Also, a semi-related question. What do the MINI54 and MKL02Z32VFG4 do since the processors already have built-in flash memory?

    Thanks.

  2. #2
    Senior Member PaulStoffregen's Avatar
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    USB requires 3 volts.

    The rest might work with lower voltage, but it's not so usable without the USB port.

  3. #3
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    I'm interested in running my Teensy 3.2 at 1.8V to facilitate interfacing with some peripherals that run at 1.8V.

    If I were to provide higher voltage to VREGIN and disconnect VOUT33 from VDD, shouldn't the Teensy core be able to run at 1.8V? As I understand it, the USB hardware gets it's power from VOUT33.

    This would be much more difficult to achieve on the LC, 3.5, or 3.6 as the pins cannot be singularly disconnected easily. This would also be useful information for anyone designing their own Teensy (MKL02/04 bootloader) powered boards.

  4. #4
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    Well, I tried what I was describing and it works!

    I lifted pin 7, added a 1uF cap from pin7 to ground, connected pin 8 to VUSB, cut the trace between VUSB and VIN, and injected 1.8V to "3v3" pin.

    Without the cap, the voltage at VREG33 was ~4.8V. I would have used a 2.2uF cap as the datasheet describes but I was in a hurry and couldn't find the right cap.

  5. #5
    Quote Originally Posted by cinderblock View Post
    Well, I tried what I was describing and it works!

    I lifted pin 7, added a 1uF cap from pin7 to ground, connected pin 8 to VUSB, cut the trace between VUSB and VIN, and injected 1.8V to "3v3" pin.

    Without the cap, the voltage at VREG33 was ~4.8V. I would have used a 2.2uF cap as the datasheet describes but I was in a hurry and couldn't find the right cap.
    Hello, I'm also interested to supply my Teensy 3.2 with 1.8V because I want access via the Teensy external 1.8V Hardware.

    I'm now a little bit confused about your pin assignment, description: "lifted pin 7 to ground, pin 8 to VUSB, and VREG33" on my teensy 3.2 I cannot find for example VREG33, and pin 7 and 8 are usual I/O's and has nothing to do with the Supply??

    thank you for support

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