how to increase the slew rate with source degeneration?

[wholx]

can someone explain how a source degeneration config works for increasing the SR?

if the circuit is composed of a differential pair followed by a common source amp then an output stage. a compensation capa is applied by connecting the Gate and Drain of the CS transistor. so the SR could be calculated as

SR = Vdsat(diff)*Wp2

where Wp2 is the sencond pole of the circuit.

in this case, how to use the source degeneration in the differential pair to increase the SR?

 

[noiseless]

In the source config, the output impedence is 1/gm, which is really small resistance. So it can generate larger output current to increase SR

 

[fantaci]

Are you sure by using the source degeneration in differential stage could increase SR? I think by increasing the second stage bias current, you could increase SR.

 

[songsong]

You can increase tail current because SR=I/C.