ring oscillator

Discussion in 'Cadence' started by selvakumar_in, Oct 20, 2003.

  1. dear all,

    these question is not regarding cadence rather its vlsi domain related
    ,since i can't find any group to discuss i am putting it here.

    for a particular process technology there is a term called ring
    oscillator inverter delay. this i got from the mosis web page.

    my query is what is the physical meaning of this parameter ?

    whether the delay value is fixed by the spice parameter values of the
    transistors of the particular process ?

    is there any group like this to discuss in the vlsi domain please
    suggest me

    with regards
    selvakumar_in, Oct 20, 2003
  2. Basically the idea is that you have a ring oscillator that consists of
    several inverters (odd number). The frequency of osculation depends on the
    delay of each inverter (the period of the oscillator should be the sum of
    the delays - i.e. 3 inverters => T = 3*DELAY_TIME). Of course the delay of
    the inverter depends on the transistor Ft.

    Back to the question - the delay time of the inverter is the delay
    introduced by the inverter - suppose you put signal at the inverter input,
    the delay time is the time it takes that the signal appears at the output.

    Hristo Brachkov, Oct 23, 2003
  3. selvakumar_in

    John Gianni Guest

    Basically the idea is that you have a ring oscillator that consists of
    In addition, I'm told folks generally test with a fanout of n at each
    interesting node m, e.g., a fanout of 1, 2, or 3 (for example) at node
    17 (for example); and then they plot the curves & measure the delay.
    John Gianni, Nov 10, 2003
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