Higher and lower bandwidth in 4 stage amplifier

[surianova]

bandwidth

hi all,

When i design the limiting amplifier that consists of 4 stages, i found out that if the first 2 stage more lower bandwidth (12G) and cascase with 2 last stage more higher bandwidth (16G), overall you can get more bandwidth (5G) compare to high bandwidth to lower bandwidth cascading only get 4G, any reason for that?

Suria

 

[IanP]

Re: bandwidth

You should have the same result regardless of the sequence...

 

[hrkhari]

Re: bandwidth

Here you should appreciate the Bode plot in obtaining the frequency ac response of the cascaded stage, lower bandwidth corresponds to lower db/decade slope compared to higher bandwidth. Hope this helps

Rgds

 

[Markie]

Re: bandwidth

If you want to exactly understand about it.

I suggest you to use open-circuit time constants method to analyze your topo.

then you will see what serversly effect your bandwidth.

If you don't know the "open circuit time constant", you can see "tomath lee".