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SN74GTL2003: GTL2003

adam walczuk1
Prodigy 40 points

Part Number: SN74GTL2003

I need to connect four SPI devices (two of them are 5V logic and another two are 3.3v logic) to 5v logic microcontroller.

i am thinking about use GTL2003, but I am not sure if it will work correct.

I am not sure about MISO line.

  • 0
    TI__Guru* 97696 points
    Hi Adam,

    I am moving this post to the translators forum. One of our apps specialists will get back to you soon.
  • 0
    TI__Expert 6330 points
    Hi Adam,

    I would like to ask you a couple questions before I make any recommendations on a device to use.

    1) What is the frequency your device is operating at?

    2) What is the drive strength of your signals?

    Regards,
    Aaron Goodson
  • 0 in reply to Aaron Goodson
    Prodigy 40 points

    Hello,

    1) up to 5MHz

    2) I am not sure what do you mean. Microcontroller is Atmega324. So outputs are like regular outputs. MISO is pulled up with internal resustance 50kohm.

    3,3V deivces - SDcard and RFM12B

    5V devices - 2x TLE6220.:

    from TLE6220 datasheet:

  • 0 in reply to adam walczuk1
    TI__Expert 6330 points

    Hi Adam,

    Given this information the GTL2003 will probably work. You will however need some additional circuitry. The diagram below is pulled directly from the datasheet and should help you setting this up. 

    You will need a 200 kohm resistor connected between your 5V supply and Gref and Dref pin. A filter cap is also recommended from the Dref pin to ground, something in the range of 0.1uF should work. You will also need some pull up resistors. From the given info, you could try 500 ohm pullups on your high side (5V), and 10 kohm on your low side (3.3V). This diagram displays translating 5V and 3.3V to 1.8V, but for your application you will only have 5V on one side and 3.3V on the other it sounds like. 

    Regards,

    Aaron