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Ron in triode constant across processes and temprature

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amriths04

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triode constant

could you refer me to any circuit or suggest me a way by which we could make the Ron of a mos (in triode), constant across processes and temprature.
 

ron of the triode

Find some papers of Czarnul and Tsividis. Czarnul discovered 4-MOSFETs resistor independent of process parameters.
 

Re: Ron in triode.

i tried searching up his papers through google but in vain.
could you point me to those specific papers which deals with stabilizing Ron across process and temprature.
 

Re: Ron in triode.

I have never heard of anyone being able to make RON independant of process and temperature. If someone was able to do, they would have process that is so good, they would dominate the market in the power managemen field because they would be able to keep their efficiency constant even at high temperatures. They would kill the market.

I honestly don't think anything exists like this exists. How can you have a device that doesn't move over process? Isn't that an impossibility? THere is no process that is so tight that it doesn't drift over time.

The fact the RDSon moves so much is why you have to make your other circuitry that is dependant on RDSon where you want to keep specs constant over process and temperatures. For instance if you are relying on RDSon for over current limit, you make your over current circuit so it tracks RDSon over process and temperature.

I dont' think you are going to have any luck finding such a device or process that can do this.
 

Ron in triode.

This Czarnul's 4-MOSFET circuit is of course tunable by gate voltages. Taking the simple model of MOSFET in the triode region, the equivalent resistance is independent of main process parameters. Surely, it is simplification --- but works fine as a tunable resistor.

For sure you will find their papers in IIIE periodics, but the idea is old, from about 80th... Czarnul expanded this idea with japanese engineers in 90th. I have no access to my library, so I cannot find you mentioned papers.

Google: Czarnul resistor --- there is a lot of info.
 

    amriths04

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Re: Ron in triode.

@haff99

i agree that one cannot make the Rdson of a "single" device independent of process and temprature but maybe we could make the effective Rds of a combination of transistors independent of process and temprature. take for example the bootstrapped switch. an external circuit is acting on a single transistor to make it more linear. i thought there might be some cirucit similar in line with that for contolling Ron too, (through some external circuitry).
 

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