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

 

Read about the static RAM cell.

 

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.
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