DC coupled multistage amplifier design...

[saadibro]

how can i design a multistage amplifier (discrete) with minimum number of stages that can give me a gain around 1000. It may be DC coupled n that's the whole hint i've got yet...Also i am supposed to be usin only dual supply(±8 V)......
pleeeez help me out..i've searched a lot on internet but "all in vain"..

 

[EmbdASIC]

well,
The fact that its DC coupled indicates, that you dont need to restore your DC point (which is the case with AC coupled circuits), after your input cap on the line. Usually you recover the DC point by some sort of 'clamp' circuit' which may be some follower like architecture.
Anways, you can implement a multistage architecture from so many options. e.g How about taking a two stage opamp with different input (first stage) and singled ended common source output stage. If incase you are driving resistive loads then you may want to add a Common drain final stage for the 'correct' output impedance ??
This is just one of sooo many options.


Hope this helps.

 

[saadibro]

main problem is that i am to use only discrete BJT's....n i havnt been though opamps till now...
secondly, i have also to get zero DC level at the last stage which must be a common collector..your hint might be helpful for me had i been through opamps in a detail..
if you can still help, it'd be great!

 

[karesz]

Hi,
Maybe good lectures for you:
h**p://books.google.ch/books?id=FbezraN9tvEC&pg=PA181&lpg=PA181&dq=discret+dc+coupled+amplifier&source=bl&ots=KXRLFGTg8c&sig=IdwG1f8DsKYrULACIo-031HyBFQ&hl=de&ei=xK47S8itFdyh_Aa74oiKCQ&sa=X&oi=book_result&ct=result&resnum=7&ved=0CDAQ6AEwBg#v=onepage&q=&f=false

www-personal.engin.umd.umich.edu/~fmeral/ELECTRONICS II/05%25c3-Discrete BJT/DiscreteAmplifierProject.pdf
K.

 

[ftsolutions]

No specs on input impedance or load impedance or bandwidth requirements ? 2 cascaded common emitter amplifiers with a gain of ~ 32 each will do what you want, but the items mentioned above are pretty critical.