Cross-gate Connection Transistor

Discussion in 'Homework Help' started by menewbie, Feb 1, 2006.

  1. menewbie

    Thread Starter Active Member

    Jan 31, 2006
    34
    0
    Right now I am reading on how to design this decision circuit with positive feedback. The circuit showed in the book uses cross-gate connection to connect two NMOS transistors. I dont understand why by using cross-gate connection, the circuit provides postive feedback.
    The circuit is connected in the following way:
    d = drain g = gate s = source b = bulk
    xxxxxx d g s b
    NMOS14 Vo+ Vo+ 0 0
    NMOS15 Vo+ Vo- 0 0
    NMOS18 Vo- Vo+ 0 0
    NMOS16 Vo- Vo- 0 0
     
  2. CoulombMagician

    Active Member

    Jan 10, 2006
    37
    0
    Read about the static RAM cell.
     
  3. menewbie

    Thread Starter Active Member

    Jan 31, 2006
    34
    0
    Ok, I can see how static RAM cell is cross gate connected. However, it is gate connected to both PMOS and NMOS. In the circuit I am trying to design, it is cross-gate connected to NMOS. The circuit creates hysteresis if the W/L ratio of M14, M16 and M15, M18 are different. What I cant understand is how does the cross-gate connection of M15 and M18 can increase the gain of the decision element.

    I have attached a picture of the circuit.
    [attachmentid=1170]
     
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