comparing CS and Cascode frequency response

[Matteo]

Rodger Rosenbaum ha scritto:

I see two differences compared to the expression in your original post.

should be 770EE-15

About the first difference: in your posted expression you have Cds1; I used the
value for Cdb1 for that.

The second difference is * instead of +. Maybe it should really be +, but in
the expression you posted it's *.

gosh ..the right expression is:

f = ( 2*PI*(Rs*Cgs1 + Cgd1*2*Rs + Rd*(Cgd2+Cdb2+Cl) + 1/gm2*(Cdb1+Cgs2) )-1

and with the values f = 2.08EE+08 Hz.. very similar to the CS's one

you sad that you got a corner frequency of 315 MHz for the CS
amplifier, and a corner frequency of 984 MHz for the cascode.

did you get these values using the simulator? they are really very
different from the values obtained from manual calculations...

 

[Rodger Rosenbaum]

gosh ..the right expression is:

f = ( 2*PI*(Rs*Cgs1 + Cgd1*2*Rs + Rd*(Cgd2+Cdb2+Cl) + 1/gm2*(Cdb1+Cgs2) )-1

and with the values f = 2.08EE+08 Hz.. very similar to the CS's one

you sad that you got a corner frequency of 315 MHz for the CS
amplifier, and a corner frequency of 984 MHz for the cascode.

did you get these values using the simulator?
Yes.

they are really very
different from the values obtained from manual calculations...

Yes, especially the cascode.

If you'll email me at r_o_d_g_e_r_r_o_s AT yahoo.com (take out the underlines in
the name), I'll send you the results of the simulations.