Help me design CMOS Op Amp

[eynasantiago]

Hi,

Please help in my project.
Design CMOS op-amp given the specs below:

Gain ≥ 70dB
Settling time ≥ 1µs
Input CMR (common Mode Range) ≥ ± 3V
CMRR(Common Mode Rejection ratio) ≥ 60dB
Output Resistance = Not applicable, 20pF capacitive load only
noise ≤ 100nV/Hz at 1KHz
Gain bandwidth project ≥ 2MHz
Slew rate ≥ 2V/µs
PSRR(Power Supply rejection Ratio ≥ 60dB
Output Swing ≥ 4V


Any reference or advise is highly appreciated..

thank you very much.

 

[Sradio]

Re: CMOS Op Amp design

you didn't make it clear, what device parameter you will be using? can only use that topology you posted on the board? and next time you better make a research before asking this kind of quesiton, since there are lots of information abt designing an useful opamp on the google.

 

[Sadegh.j]

Re: CMOS Op Amp design

Do you have to change W and L. What should you do? what technology file are you going to use?

 

[eynasantiago]

Re: CMOS Op Amp design

We just started our Analog Design class, thats why everything's new to me. Our instructor introduce Electric 6.03 to us and I am just in the process of familiarizing myself with the software. In most examples that she gave us, the model is bsim3v3 at level 8.

I'll appreciate it really if you can teach me how to start with it, or if you can refer a reading material that is perfect for starters.

Thank you very much.

 

[eynasantiago]

Re: CMOS Op Amp design

Technology: CMOS

 

[maofeng]

Re: CMOS Op Amp design

There is a free OTA complete reference design for you to check out:

**broken link removed**

 

[keoiuser]

Re: CMOS Op Amp design

try to look at this docs

 

[test_123]

CMOS Op Amp design

which process, such as minium channel length?

 

[eynasantiago]

Re: CMOS Op Amp design

i cant understand the question..

 

[balan]

Re: CMOS Op Amp design

Hi,
Start with differential stage first and then integrate it, you can follow the procedure given in "CMOS analog design" book by Philip Allen and Hollberg.


Thank you

 

[oht993]

CMOS Op Amp design

Hi
you should read gray's ch6
then read allen''s op-amp chap.
you will get the idea about miller OTA.
thanks,

 

[Sadegh.j]

Re: CMOS Op Amp design

in designing a circuit, you should first learn what the whole circuit does, the function of each block and of each transistor.

The next step is to start a very rough hand calculation, estimate Ws and Ls and try to concentrate on all specs at the same time, gain, phase margin, band width, etc.

Now that you have the BASIC sizing, what you have to do is to enter these values. You will see that nothing is working properly. You will have transistors in the triode region, and all. So check the DC voltages and first try to make sure that everything is in saturation.

Now work on the specs. Experiment and play for about an hour and watch the trends. You will see that, lets say, the gain of the circuit is very sensible to the L of one transistor while other transistors do not affect it that much.

After observing the trends, come back to theory and try to explain it to your self.

After this, go to your design and try until you get the desired output.

Hope that it helps.

 

[yschuang]

Re: CMOS Op Amp design

The following paper migh be helpful.