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.

How to generate bias voltage for OpAmp...

Status
Not open for further replies.

firsttimedesigning

Full Member level 1
Joined
Jul 4, 2007
Messages
97
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,288
Activity points
2,241
I am looking for a circuit that can generate the bias voltage for the opamp that I have designed...so far that circuits I have looked at are either supply or temperature dependent...is there any circuit out there that does not use diode and can generate the bias voltage for opamp?
 

lladnar23

Full Member level 4
Joined
Mar 20, 2006
Messages
197
Helped
36
Reputation
72
Reaction score
3
Trophy points
1,298
Activity points
2,482
You can use a peaking voltage ref (check G&M) or you can use a VT reference from the MOS Threshold voltage.
 

firsttimedesigning

Full Member level 1
Joined
Jul 4, 2007
Messages
97
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,288
Activity points
2,241
thank you for replaying...but i dont see any peaking voltage ref...the only thing i saw is peaking current ref...maybe i can get the voltage that i want by putting a resistor on top of M2 but the thing i am worried about is that when i fabricate the chip, the resistor might have a 20% error in the resistance.....
 

lovexxnu

Junior Member level 1
Joined
Dec 14, 2007
Messages
19
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Activity points
1,372
Why do you need the bias voltage?

bias current is OK, what you truely need is just current.
 

lladnar23

Full Member level 4
Joined
Mar 20, 2006
Messages
197
Helped
36
Reputation
72
Reaction score
3
Trophy points
1,298
Activity points
2,482
Sorry - I meant to say peaking current reference.
You're correct that you might see some process spread if you use something like a resistor. You could get around that by biasing with an off-chip resistor, if that is an option.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top