THE INVERTERS
DIGITAL GATES
Fundamental Parameters

Functionality

Reliability, Robustness

Area

Performance
»
Speed (delay)
»
Power Consumption
»
Energy
Digital Integrated Circuits © Prentice Hall 1995
Introduction
Introduction
Noise in Digital Integrated Circuits
V
DD
v(t)
i(t)
(a) Inductive coupling (b) Capacitive coupling
(c) Power and ground
noise
Digital Integrated Circuits © Prentice Hall 1995
Introduction
Introduction

V
IL
V
OL
Undefined
Region
V(x)
V(y)
V
OH
V
OL
V
IH
V
IL
Slope = -1
Slope = -1
Digital Integrated Circuits © Prentice Hall 1995
Introduction
Introduction
Definition of Noise Margins
V
IH
V
IL
Undefined
Region
"1"
"0"

, ...
v
0
, v
2
, ...
(b) Regenerative gate
f(v)
finv(v)
finv(v)
f(v)
(c) Non-regenerative gate
v
0
v
1
v
2
v
3
v
4
v
5
v
6
...
Digital Integrated Circuits © Prentice Hall 1995
Introduction
Introduction

1.0
2.0
3.0
4.0
5.0
V
out
(V)
V
M
NM
H
NM
L
Digital Integrated Circuits © Prentice Hall 1995
Introduction
Introduction
Delay Definitions
t
pHL
t
pLH
t
t
V
in
V
out
50%
50%

t
p
×
N
Digital Integrated Circuits © Prentice Hall 1995
Introduction
Introduction
Power Dissipation
Digital Integrated Circuits © Prentice Hall 1995
Introduction
Introduction
CMOS INVERTER
Digital Integrated Circuits © Prentice Hall 1995
Introduction
Introduction
The CMOS Inverter:
A First Glance
V
DD
V
in
V
out
C
L
Digital Integrated Circuits © Prentice Hall 1995
Introduction
Introduction
CMOS Inverters
Polysilicon

Introduction
Introduction
CMOS Inverter: Steady State Response
V
DD
V
DD
V
out
V
out
V
in
= V
DD
V
in
= 0
R
on
R
on
V
OH
= V
DD
V
OL
= 0
V

)
= 0.69 R
on
C
L
t
V
out
V
DD
R
on
C
L
1
0.5
ln(0.5)
0.36
Digital Integrated Circuits © Prentice Hall 1995
Introduction
Introduction
CMOS Properties

Full rail-to-rail swing

Symmetrical VTC

Propagation delay function of load
capacitance and resistance of transistors
