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Unformatted text preview: ECE3050 Homework Set 5 1. For K = 1.78 mA/ V2 , VT O = 1.5 V, V + = 18 V, R1 = 110 kΩ, R2 = 68 kΩ, RD = 0, and
RS = 1 kΩ, write the bias equation, solve for ID , and verify that the MOSFET is biased in the
saturation region, i.e. its active mode. [ID = 3.897 mA, VDS = 14.10 V, VGS − VT O = 1.480 V] 2. Add a resistor R3 from gate to source for the circuit in problem 1. (a) Show that
VGG = V + R2 k (R3 + RS )
RS
+ IS
× R1 kR2
R1 + R2 k (R3 + RS )
RS + R3 + R1 kR2
RGG = R1 kR2 k (R3 + RS ) VSS = R2
V+
×
× RS
R1 + R2 k (R3 + RS ) R2 + R3 + RS
RSS = (R1 kR2 k + R3 ) kRS (b) For R3 = 20 kΩ, write the bias equation, solve for ID , and verify that the MOSFET is
biased in the saturation region. [ID = 0.492 mA, VDS = 17.41 V, VGS − VT O = 0.526 V]
3. Add a resistor R4 from drain to source for the circuit in problem 1. Show that
VSS = V + RS
RD
− ID
RS
RD + R4 + RS
RD + R4 + RS
RSS = RS k (R4 + RD ) VDD = V + R4 + RS
RS
+ IS
RD
RD + R4 + RS
RD + R4 + RS
RDD = RD k (R4 + RS ) 1 ...
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This note was uploaded on 05/25/2011 for the course ECE 3050 taught by Professor Hollis during the Summer '08 term at Georgia Tech.
 Summer '08
 HOLLIS

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