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.

Register Log in

we say CMOS is more reliable than BJT,why?

Status
Not open for further replies.
H

hsiangleung

Junior Member level 2
Joined
Nov 22, 2013
Messages
21
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
151
CMOS continues its dominance over BJT for many reasons. One of them I found is CMOS is more reliable. What does that mean? I interpret it as CMOS has less leakage current while BJT requires base current. is it right? how do we understand cmos more reliable?
 

We can drive the CMOS circuit with minimum current.

BJT is a current controlled device.

CMOS is voltage controlled device.

So, to perform simple logical operation with BJT it consumes more current when compared to CMOS.

And we use battery as power source in portable devices.

In the case of BJT, the battery will drain soon (than CMOS).
 
Thanks for your attention. As you mentioned, CMOS is power efficient for logical operation. That is true. but does reliability here mean power efficiency?
snishanth512 said:
We can drive the CMOS circuit with minimum current.

BJT is a current controlled device.

CMOS is voltage controlled device.

So, to perform simple logical operation with BJT it consumes more current when compared to CMOS.

And we use battery as power source in portable devices.

In the case of BJT, the battery will drain soon (than CMOS).
Click to expand...
 

I don't see why CMOS should be considered more reliable than BJT for small signal or digital ICs.

MOSFETS may be considered more rugged than BJT power transistors, if only because they don't suffer from secondary breakdown.
 

"We", Kemo Sabe?

I'd say well more than half of the high reliability ICs I've
designed, have been on bipolar technologies.

You can break either one, but MOSFETs have classes of
reliability problems (oxide wearout, hot carrier, NBTI) in
-normal- operation that BJTs simply don't. Vertical BJTs,
anyway - laterals are exposed to a lot of low quality
oxide over the base. And yet outside of some abnormal
environments, even these seem to do fine on a lot of
parts that have been on the job for many decades.

To paraphrase Bob Marley, "no thin ox, no cry".
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top