EE 115C, Winter 2009, HW #4 (due 2/18/2010)
Problem 1:
(Inverter Power Consumption)
For the circuit in Figure 1, assume that the input
V
in
is a periodic square wave signal (called “clock”) of frequency 400 MHz, and has a rising
transition time (from 10%90% of V
DD
) of 0.4 ns and a falling transition time (from 90%10% of
V
DD
) of 0.4 ns.
Suppose that V
DD
= 1.0 Volts,
C
GN
’ = C
GP
’ = 2.0 fF/
μ
m, C
DN
’ = C
DP
’ = 1.5 fF/
μ
m, R
N
’ = 1.25 k
Ω

μ
m, and R
P
’ = 3 k
Ω

μ
m, and the transistors have the following properties:
For the first inverter in the figure:
a)
Find the dynamic (switching) power consumption.
b)
Find the short circuit power consumption.
Assume that the short circuit current pulses are
triangular in shape: they peak when V
in
= V
DD
/2.
Assume also that the peak short circuit cur
rents are equal for rising and falling transitions: I
peak_sc_LH
= I
peak_sc_HL
.
(Hint: You need to de
termine the short circuit duration, t
SC
and the peak short circuit current, I
peak_sc_LH
; since we
assumed that I
peak_sc_HL
= I
peak_sc_LH
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 Spring '10
 N/A
 Frequency, Power consumption, Square wave, Vin, dynamic power consumption

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