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Help--about Ron of POWERMOS

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firry

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hi, who can tell me how to simulate the Ron of Power MOS FET and get a typical value??? thanks
 

paulux

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It depends on Vds of the PowerMOS, e.g Vds=0.2, Vgs=Vdd.
 

firry

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paulux said:
It depends on Vds of the PowerMOS, e.g Vds=0.2, Vgs=Vdd.

the FET operate as a resistor when it works in deep triode region with the condition Vds<<2(Vgs - Vth),but the range of the condition is very large.
when simulation, use Ron=Vds/Id, we can get a curve of Ron. but Ron is not a
constant value, how can i get a typical value?
 

xerxer

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This problem is very difficult .good .appaulse
 

paulux

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what is the usage of your typical Rds? I think that different situation requires different perspective for interpreting "typical Rds".
 

firry

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paulux said:
what is the usage of your typical Rds? I think that different situation requires different perspective for interpreting "typical Rds".

There is a certain value,such as 300mΩ, of the POWER MOSFET's Ron in some chip datasheet. How can i give my POWER MOSFET a certian Ron value?
 

paulux

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I think you have to check the measurement condition of the datasheet specified or check other comparable device specification/measurement conditions to do your measurement.
 

xerxer

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The question lies in how to simulate the Ron in spice .
 

firry

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paulux said:
I think you have to check the measurement condition of the datasheet specified or check other comparable device specification/measurement conditions to do your measurement.
hi,paulux
Thanks for replied.
The datesheet have not specified the measurement/specification conditions.
I want to choose the minimum value but it maybe has some problems.
 

wanily1983

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i think the typical Ron is measured in the typical condition the MOS used, e.g vgs=5,vds is very small and the MOS can be regarded to work in deep linear region, then calculate the Ron just using Vgs and the other device parameter such as W/L , Kp etc.
 

cheen

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generally, for powermos Ron, Vds=0.1V / 0.2V; Vgs is usually given by the process. Say, for a 5V Vgs process, use Vgs=5V; for a 25v Vgs process, use Vgs=25v.
According to my experience :)
 

watersky

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Simulate a resistor and power mos between vdd and gnd. Power mos need be post file from layout. Estimate Ron from data of foundry, and adding resistor of metal and via.
 

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