OpAmp architecture suggestion

[hacksgen]

op amp architecture

Hi friends,

i have to design an opamp in 130nm umc foundry process.This is going to be used in a dual slope adc for the integrator and comparator part .The inputs to this opamp will be biomedical signals like eeg or ecg which have frequencies like from few hertz to 100-200 hz. The supply voltage is 1.2v and i require a opamp with atleast 80db or more gain with phase margin of 60 degrees.Also the opamp must be a fully differential one.ICMR should be around 70-80% of supply voltage and output swing close to ICMR range. UGBW should be above 2MHz

Any suggestions for which kind of opamp architecture which is suitable for this kind of process and specs.

thanks for your help.

 

[jnuhope]

opamp architecture

I would use two stage opamp with folded cascode as first stage.

I remember ISSCC 2007 has several papers using this structure in Nyquist rate ADC session.

 

[horsehill]

various op amp architectures

OTA can be the first stage

 

[peterwang]

operational amplifier architecture

You can also check out a sample OPAMP design at:

**broken link removed**

 

[theNewMember]

architecture op-amp

You have to find out by any means what the load will be exactly. When it will be
a resistance, you may have to add a second stage. Folded cascode seems to be a good idea, but this architecture has a high impedance at the output, so the gain will break down strong.

Maybe class AB amplifier as 2nd stage....