Continue to Site

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.

Push-Pull output resistance Value

Status
Not open for further replies.

mirror_pole

Member level 2
Joined
Nov 22, 2020
Messages
45
Helped
0
Reputation
0
Reaction score
1
Trophy points
8
Activity points
481
Hello guys,

Simple question,: if i use a push pull output stage with additional cascode transistors what is the range of the output resistance i can expect? So far i mostly analysed circuits without having a feeling for the values i can expect. Is it possible to get a 600k ohm output resistance?
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
23,018
Helped
4,715
Reputation
9,446
Reaction score
5,087
Trophy points
1,393
Activity points
152,504
Hi,

No, not exactly.

Maybe you could refine your question.

Klaus
 

Audioguru

Advanced Member level 5
Joined
Jan 19, 2008
Messages
9,440
Helped
2,150
Reputation
4,300
Reaction score
2,002
Trophy points
1,393
Location
Toronto area of Canada
Activity points
59,559
Why do you want such a high output resistance? If you want a current source then make a current source.
Most outputs have a very low output resistance so that there is very little voltage loss and very little high frequencies loss.
 

mirror_pole

Member level 2
Joined
Nov 22, 2020
Messages
45
Helped
0
Reputation
0
Reaction score
1
Trophy points
8
Activity points
481
Im sorry, i forgot to mention that its part of a one stage OTA Topologie. Since OTAs have a high output resistance they act as a voltage controlled current source at the output, so i thought this value of 600kohm is somewhere normal. I build an OTA in cadence and just want to get a feeling for the values i can get. Its my second design so far.
 

Dominik Przyborowski

Advanced Member level 4
Joined
Jun 6, 2013
Messages
1,174
Helped
501
Reputation
1,006
Reaction score
496
Trophy points
1,363
Location
Norway
Activity points
8,836
Output impedance depends to output stage current, used process, and topology.
Negative feedback decrease output impedance by open loop gain (to value which is inverse OTA's transconductance).

In general the answer for your question is "yes, it is possible" like any other value.
 

crutschow

Advanced Member level 5
Joined
Feb 22, 2012
Messages
4,204
Helped
967
Reputation
1,932
Reaction score
1,025
Trophy points
1,393
Location
Colorado USA Zulu -7
Activity points
23,835
Negative voltage feedback reduces output impedance, but negative current feedback increases output impedance.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top