What does it mean that continuous cmfb is fast?

[ljy4468]

continuous & sc cmfb

Hi every body?

i've a question about continuous&sc cmfb circuit

I know continuous cmfb's speed is fast
but output swing is limit.
& sc cmfb is good at output swing, but weak at noise.

And my question is what does that mean that conti-cmfb is fast?
Fast means good performance when input is high frequency????
I don't know what exactly means "fast".

Someone could help me what does that means????????

And cmfb's unity gain freq is higher than main opamp?
If so, how I measure its UGF?
could I measure it with applying input and see output (vdb) like an opamp case?
I don't know...

Plz help me and have a good day

REGARDS

 

[rambus_ddr]

Re: continuous & sc cmfb

I think that the "fast" is the output response to the input changing, sometime is the big bandwidth.
the UGF measure, open the close loop and a 1F cap is added in input and a large resistor 1M resistor added between output and input. then do ac analysis, see the ufg.