The data sheet for a certain enhancement-type MOSFET reveals that I_{D(on)} = 10 mA at V_{GS} = −12 V and V_{GS(th)}= −3 V. Is this device p-channel or n-channel? Find the value of I_D, when V_{GS} = −6 V.
Chapter 3
Q. 3.6
Step-by-Step
Verified Solution
Given that
I_{D(on)}=10 mA;V_{GS}=-12 V and V_{GS(th)}=-3V.
Since the value of V_{GS} is negative for the enhancement-type MOSFET, this
indicated that the device is p-channel. Also V_{GS(th)} = V_t.
We know that the saturated drain current is given by
I_D=K[V_{GS}-V_{GS(th)}]^2
I_{D(on)}=K[V_{GS}-V_{GS(th)}]^2
or
10=K[-12-(-3)]^2=81 K
K={10}/{81}={0.12 mA}/{V}
Substituting this value of K and V_{GS} (equal to −6) in the equation of I_D above,
I_D=0.12[-6-(-3)]^2=1.08 mA Ans.