How to design such an op amp?

[winsonpku]

Dear all:
I will design such an op amp, the speficaiontons are as follows:
Output swing VPP is 2V, input singnal is 37MegHz, output capacitance load is 5pF.
power supply is 3.3V. Op amp is used as a unity-gain buffer to drive other circuit.
i am not clearly about these specifications,who can tell me how to derive the op amp'DC gain and GBW. and how to design the op amp.
Any advice is welcom, thanks all!

Best regards,
Winson

 

[mengwang]

use mosfet differential amplifier

 

[swkimaz]

I recommend a single stage folded-cascode amplifier becasue you need high speed, moderate gain, and 2V output swing specs.

 

[tanuki]

Take a look at these buffers **broken link removed**

For you application, gain flatness over the signal's spectrum should be the most important condition.

This link has a selection table: **broken link removed**

Many other semiconductor companies have similiar buffers.

Read the Application Notes for video buffers and video multiplexors; you'll also find example circuits that should work for your application.

 

[gte582w]

Let's see, unit-gain buffer => open loop GBW will be the close loop 3dB BW.
Input 37 MHz, suppose you can tolerate just half dB gain drop then you 3dB
BW will be 3X that which results in about 100 MHz. Given 5pF cap, you can then
estimate the input gm, etc.