Alex Liao
Member level 4
Hi, I am looking at the inversion coefficient/facotr (IC) used by EKV people. Inspired by this IC, D. M. Binkely and D. Foty. applied it to analog sizing applications.
I think IC is a parameter to express the bias status/condition of a MOSFET, so it should be a DC-op parameter, because as mentioned in EKV's book "Charge-based MOS Transistor Modeling" in 2006, "The notion of inversion coefficient is qualitatively equivalent to that of gate voltage overhead."
I have the following basic question:
A. Is IC a DC-op parameters that can be obtained after finishing a SPICE simulation (has to use EKV model?)
B. From the same book, the defition of IC,
* IC=max(if=IF/Ispec, ir=IR/Ispec),
where IF and IR are the Forward-current and Reverse-current to express that the drain current is the superposition of independent and symetrical effects of the source and drain voltages. So does this mean IC is a parameter defined in all working regions? (in both triode region (or linear region) and saturation region, ignore the cut-off region)
B-1. I know given Vds > Vdsat (saturation region), and when Vgs varies, the MOSFET works from weak inversion to moderate inversion and to strong inversion as can be reflected by the IC factor, are the three inverison-regions also clearly defined and discussed in triode region (when Vds < Vdsat or Vds < Vgs - Vth)? Not sure if this question make sense or not, because I did not find any spcific materials accouting for this point. This will lead to my Question-C.
C. I did see in Binkley 2003's TCAD paper, the IC "in saturation" is defined by,
* IC = ID / ( 2nk(W/L)UT^2 ).
Is there an equation that link IC and ID in triode region?
I konw IC in saturation can be helpful for sizing a Opamp, but I am really not sure about the story of IC in triode region, some circuits use triode region MOSFET as a Resistor or load, so it is not only used in digital application as switches, and thus can be important.
Appreciate for any response for the questions! thanks.
I think IC is a parameter to express the bias status/condition of a MOSFET, so it should be a DC-op parameter, because as mentioned in EKV's book "Charge-based MOS Transistor Modeling" in 2006, "The notion of inversion coefficient is qualitatively equivalent to that of gate voltage overhead."
I have the following basic question:
A. Is IC a DC-op parameters that can be obtained after finishing a SPICE simulation (has to use EKV model?)
B. From the same book, the defition of IC,
* IC=max(if=IF/Ispec, ir=IR/Ispec),
where IF and IR are the Forward-current and Reverse-current to express that the drain current is the superposition of independent and symetrical effects of the source and drain voltages. So does this mean IC is a parameter defined in all working regions? (in both triode region (or linear region) and saturation region, ignore the cut-off region)
B-1. I know given Vds > Vdsat (saturation region), and when Vgs varies, the MOSFET works from weak inversion to moderate inversion and to strong inversion as can be reflected by the IC factor, are the three inverison-regions also clearly defined and discussed in triode region (when Vds < Vdsat or Vds < Vgs - Vth)? Not sure if this question make sense or not, because I did not find any spcific materials accouting for this point. This will lead to my Question-C.
C. I did see in Binkley 2003's TCAD paper, the IC "in saturation" is defined by,
* IC = ID / ( 2nk(W/L)UT^2 ).
Is there an equation that link IC and ID in triode region?
I konw IC in saturation can be helpful for sizing a Opamp, but I am really not sure about the story of IC in triode region, some circuits use triode region MOSFET as a Resistor or load, so it is not only used in digital application as switches, and thus can be important.
Appreciate for any response for the questions! thanks.