Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics 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.

Transistors in Saturation

Status
Not open for further replies.

ammadupm

Newbie level 5
Joined
Apr 15, 2009
Messages
10
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Activity points
1,342
How to put transistor in saturaqtion region.......plz give me some examples
 

ammadupm

Newbie level 5
Joined
Apr 15, 2009
Messages
10
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Activity points
1,342
i am designing cascoded amplifier using MOSFET, there i am facing this problem (saturation)...mathematically i calculate that my all transistor are in saturation but when i run it on mentrographics using eldo (TSMC 0.18), it shows different result...............this is my problem brother.........
 

haykding

Member level 2
Joined
Feb 4, 2009
Messages
51
Helped
5
Reputation
10
Reaction score
4
Trophy points
1,288
Location
Armenia
Activity points
1,554
Try to solve problem with help of simulation .. Sometime math doesn't help !!!
 

sutapanaki

Advanced Member level 4
Joined
Nov 2, 2001
Messages
1,303
Helped
512
Reputation
1,024
Reaction score
464
Trophy points
1,363
Location
US
Activity points
10,750
saturation is by definition when Vdsat<Vds.
This said, in many cases Vds is dependent on the circuit itself. So, if you post your circuit with annotated operating point, may be someone will tell you what is going wrong.
 

dkace

Full Member level 6
Joined
Jun 13, 2002
Messages
396
Helped
32
Reputation
64
Reaction score
7
Trophy points
1,298
Location
Greece
Activity points
3,557
How many times we think that out transistor works ok in Saturation but it doesn't!

Check (by graph not by annotation in the schematic) the voltages in Gate, Drain and Source.

Then check the vth of the transistor. There might be a fault there but it's the only you have.

If Vds>Vgs-Vth ( as in theory) then you are well in saturation.

If this is the case but not in saturation, you are loosing an info regarding voltages.

D.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top