Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

some basic questions on LNA

Status
Not open for further replies.

sreechoudhary

Junior Member level 3
Joined
Dec 2, 2004
Messages
30
Helped
2
Reputation
4
Reaction score
0
Trophy points
1,286
Activity points
235
hai all

I am very having some basic doubts please give me reply.

1.I am doing LNA design ,for single ended LNA ..when i am doing the simulations for single ended LNA and i am trying to get relation between overdrive voltage and IIP3 (keeping length constant and varying width).for single ended with out cascode stage it IIP3 will be decresing after some point.please explain me the reason .
2.for single ended with cascode (what will be happen) for the same corcuit.
3.basic question:-RLC circuit even provide amplification ..why we need transistor after tank ciruit.
 

khouly

Advanced Member level 5
Joined
Oct 20, 2003
Messages
2,368
Helped
461
Reputation
916
Reaction score
101
Trophy points
1,343
Location
EGYPT
Activity points
13,244
when u increase the width of the transistor the gain increase coz ur increasing the Gm
so as gain increase the nonlinaer effects as IIP3 and gain compression point decrease

but the RLC doesnot give amplification coz it is a passive network , so u must need a transistor

wish this help

khouly
 

tieuquaybk

Member level 4
Joined
Apr 30, 2005
Messages
75
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,824
U can use L transformer to obtain amflification . ( eailier i'd discused with my teacher about it , at that time i had to write program on Matlab to calculate circuit 's parameters . I did some mistakes , and didn't get any amplification . I thought as khouly that passive netword does not give amplification . After doing more accurately program i got it in the end . :p
the reason why we'd use transistor instead of RLC may be that RLC elements have bigger size . it bandpass 's narrow , further more they bring more loss (cos L-transfomer don't work with DC current while transistor convert part of suppliment into useful signal)
 

No one

Full Member level 5
Joined
May 11, 2005
Messages
287
Helped
4
Reputation
8
Reaction score
2
Trophy points
1,298
Activity points
3,424
Hello;
What software do you use for simulation?
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top