[SOLVED] Urgent help please! every one please help ! High G.B (100mhz) 2stage opamp

[tavoosi]

Hello every one
i need to desgin an opamp with this specifications:

Process 0.25µm CMOS
VDD 1.5V
VSS -1.5V
Load 1pF
ADM0 (low-Frequency open-loop small signal gain) ≥ 1000 V/V
ACM0 (low-Frequency open-loop small common-mode gain) ≤ 0.1 V/V
Phase margin ≥ 60°
Unity gain frequency ≥ 100MHz
Slew rate ≥ 10 V/µs
Nominal input and output common-mode voltage 0V
Output voltage swing (peak to peak) ≥ 1.6V
Power ≤ 1mW

can any one say what kind of topology sall i choose? i read in allen book that a 2 stage book will give you only 10 mhz G.B . so to get 100 mhz G.B what should i do?
i have used this but it so wrong!! View attachment L160-MOSOpAmpDesign(2UP).pdf
if you have any sample that helps me please say
thanks.

 

[drknownothing]

In order to achieve 100MHz UGF you need to have a very small output resistance, and you need single stage topology because for each added stage UGF will drop significantly.

I would say try minimal single stage topology, with small output resistance. You need a large input bias current to boost up the transconductance.

 

[tavoosi]

do you have any schematic or refrence for me? i need to see some examples. thanks

 

[drknownothing]

You can refer to the simplest (most basic) single stage topology, with current mirror load. You can find the schematic in almost every analog design book.

 

[tavoosi]

thanks, i choosed the folded cascode single stage (differential pair single ended) and i reached to 300 MHz - 61 degree phase margin - 0.9 mwatt power dissipation . thanks for guiding