can anyone help me design a two-stage opamp for 0.18um tech?

[fareast]

0.18um cmos two stage opamp

i need an opamp to use in my 2nd-order low-pass filter.the specs are:
*fc=400kHz
*use butterworth response
what are the best specifications for an opamp to use in that lpf?

i had designed a two-stage opamp but i don't know wether it is right or wrong.also,i don't know wether it is suited to use in that lpf or not.how do i determine it is the correct one?i didn't understand much about the magnitude response graph (dB vs Hz).by the way,how's the output of an opamp?i had searched in all books but end up with nothing.all the books display the typical frequency of the magnitude response for an opamp.if we give a sinus input for the opamp,is it the output will also be a sinus?

 

[pk3316]

If you wanna design a filter, I think you'd better looking up some active filter design books, there are many active transconductance circuit suitable for filter may not limited to opamp

 

[Chethan]

Re: can anyone help me design a two-stage opamp for 0.18um t

i need an opamp to use in my 2nd-order low-pass filter.the specs are:
*fc=400kHz
*use butterworth response
what are the best specifications for an opamp to use in that lpf?

i had designed a two-stage opamp but i don't know wether it is right or wrong.also,i don't know wether it is suited to use in that lpf or not.how do i determine it is the correct one?i didn't understand much about the magnitude response graph (dB vs Hz).by the way,how's the output of an opamp?i had searched in all books but end up with nothing.all the books display the typical frequency of the magnitude response for an opamp.if we give a sinus input for the opamp,is it the output will also be a sinus?

Hi
U can use the foll link to know the opamp specs for ur LPF
**broken link removed**

It is very helpful if u r designing a filter for the first time.