Sistemi Elettronici

1

2
THE INVERTERS
3
DIGITAL GATES Fundamental Parameters

• Functionality
• Reliability, Robustness
• Area
• Performance
• Speed (delay)
• Power Consumption
• Energy

4
Noise in Digital Integrated Circuits
5
DC Operation Voltage Transfer Characteristic
6
Mapping between analog and digital signals
7
Definition of Noise Margins
8
The Regenerative Property
9
Fan-in and Fan-out
10
The Ideal Gate
11
VTC of Real Inverter
12
Delay Definitions
13
Ring Oscillator
14
Power Dissipation
15
CMOS INVERTER
16
The CMOS Inverter A First Glance
17
CMOS Inverters
0.2
m
m
2l
Out
In
GND
18
Switch Model of CMOS Transistor
19
CMOS Inverter Steady State Response
20
CMOS Inverter Transient Response
21
CMOS Properties

• Full rail-to-rail swing
• Symmetrical VTC
• Propagation delay function of load capacitance
  and resistance of transistors
• No static power dissipation
• Direct path current during switching

22
Voltage TransferCharacteristic
23
PMOS Load Lines
24
CMOS Inverter Load Characteristics
25
CMOS Inverter VTC
26
Simulated VTC
27
Gate Switching Threshold
28
MOS Transistor Small Signal Model
29
Determining VIH and VIL
30
Propagation Delay
31
CMOS Inverter Transient Response
32
CMOS Inverter Propagation Delay
33
Computing the Capacitances
34
CMOS Inverters
0.2
m
m
2l
Out
In
GND
35
The Miller Effect
36
Computing the Capacitances
37
Impact of Rise Time on Delay
38
Delay as a function of VDD
39
Where Does Power Go in CMOS?
40
Dynamic Power Dissipation
2
Energy/transition C
V
L
dd
2
Power Energy/transition
f
C
V

f
L
dd
Not a function of transistor sizes!
Need to reduce C
, V
, and
f
to reduce power.
L
dd
41
Impact ofTechnology Scaling
42
Technology Evolution
43
Technology Scaling (1)
Minimum Feature Size
44
Technology Scaling (2)
Number of components per chip
45
Propagation Delay Scaling
46
Technology Scaling Models
47

Scaling Relationships for Long Channel Devices
48

Scaling of Short Channel Devices