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AL422 speed limits

  1. Jul 5, 2012 #1
    Hello. I use a Fifo IC AL422B with a 1 MHz write clock and a 625 kHz read clock. I just discovered that 1 MHz is the low speed limit for the clocks. I can speed up the write clock to 2 MHz but unfortunately I can't change read clock speed. As these clocks ( or at least one of them) are used for refresh cycles, do you think that increasing write speed will be sufficient to insure a proper way of work ?
  2. jcsd
  3. Jul 6, 2012 #2


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    Staff: Mentor

    The datasheet says it is self-refreshing, so that doesn't look like an issue:


    However, it appears to have the same specs for both the Write and Read clocks -- 20ns to 1us period. You aren't going to be able to read it at 625kHz if I'm reading that specification correctly.

    Do you have the circuit working at 625kHz?
  4. Jul 7, 2012 #3
    Thanks for reply. Reading is done by an old PC (300 MHz) through Centronics // interface and I've no way to increase this speed
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