[SOLVED] Relationship between Slew Rate and GBW

[petelee]

I encountered this equation in CMOS conventional 2-stage opamp theory.

Slew rate = (VGS-VTH)*WT

VGS-VTH is bias condition on input transistors. And WT is Gain-bandwidth product.

I'd like to know how to get the equation and understand the reasoning on it. Any paper or article about it would be really appreciated. I'm really curious.

 

[monsoon]

Assuming a two stage miller compensated opamp, slew rate is given by I/Cc, where I is the tail current source of first stage, Cc is the miller cap. Also gm=I/(Vgs-Vth) . Slo slew rate= gm*(Vgs-Vth)/Cc. gm/Cc is the unity gain frequency (Gain -BW product).

 

[petelee]

Dear Monsoon,

I appreciate your reply. Now I clearly understand it. This eda board really helps whenever I have a technical question. :-o