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Thread: LVTTL for Teensy 4.0

  1. #1
    Junior Member
    Join Date
    Dec 2020

    LVTTL for Teensy 4.0

    This might be a bit specific and probably a bit offtopic, but here it goes. I am trying to use AD5370 as my SPI downstream device. According to the AD5370 documentation, it can work at 2.5 V LVTTL-compatible when operating from a 2.5 V to 3.6 V DVCC supply.

    I have been previously powering my AD5370 with a DVCC of 5.0V, which is in the recommended range of 2.5V-5.5V. I have been reading about the strict 3v3 limit of teensy. Do you think

    • I need a logic level converter to work with Teensy 4.0?
    • Or can I get away with supplying my AD5370 with 3.6V on the DCC line, and common ground both devices?

  2. #2
    Deleted User
    You could power the digital section DVcc from Teensy's 3.3V. And Vdd, Vss and Vref according specs. The level shifting happens internally. So 3.6V on DVcc is not needed.
    Powering DVcc higher than 3.3V will source a current of max 200ľA, if 5V, with an overvoltage of 1.2V (5-0.5-3.3) on the digital pins, already pushing Teensy 4.x input protection. So this could fry Teensy soon. Use 3.3V as DVcc.

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