How to design a sense amplify in SRAM?

[pasher]

Hello everybody,
I want to use a sense amplify in SRAM, the circuit was found in book, but I don't know how to set W/L of MOS .
How to begin this design , what steps does the design need?

 

[jesseyu1984918]

The gain of the circuit is decided by two things, one is Vdsat, the other is the channel length of the circuit. The other thing is the slew rate you want, as how much current you need for the circuit speed.

 

[pasher]

Thanks jesseyu1984918.

How can I get the value of Vdsat, define it by myself or need to calculate based on the circuit?

 

[jesseyu1984918]

I always see how much supply you can get at first, then decide what will the vdsat be cause the vdsat could be decided by sizing the transistor. usually it is recomended to be 1/10 of the supply voltage, say, 2V, a vdsat of 200mV will turns out to be just balance for performance, however, this would be case by case.

 

[pasher]

Assume VDD=1.8v, Vtn=0.58, Vtp=-0.6v, BL&BLB will be precharged to 1.38v, the Cload on output is 50ff, and I want the amplify can finish work in 1ns.