Page 1 /CCUT T.-C. Huang Oct. 2002 TCH CCUT Introduction to IC Introduction to IC Design Design Tsung-Chu Huang ( 黃黃黃 ) Department of Electronic Eng. Chong Chou Institute of Tech. Email: [email protected] 2003/9/29
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Introduction to IC DesignIntroduction to IC Design
Tsung-Chu Huang( 黃宗柱 )
Department of Electronic Eng.Chong Chou Institute of Tech.
Email: [email protected]
2003/9/29
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2003/9/29Switch Model and Complex Gate
Relay Logic MOS Switch – Why CMOS? Eular Path Complex Gate Homework #1
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Relay (Switching) Logic
1. 基本 Relay (Switch) Logic 只能表達 AND 及 OR 功能
2. 註:一組邏輯能組合出 {And, Or, Not} 稱Complete( 完整 ) ,例如 {NAND} 或 {NOR}
3.例: F=A(B+C)+D C
B
D
A
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Basic Model of a MOSFET
0
0.5
1
1.5
2 2.5
3
IDSS5
S9S13S1
7S21S2
5S29
0
20
40
60
80
100
120
140
160
Ids
VdsVgs
MOSFET Model
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Simple Switch Modelof an n-MOSFET
Vth
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Switch Intention
S
D
G B
S
D
G
0
0
D
S
G
V(1)
V(1)-Vth
D
S
G B
D
S
G
1
1 S
D
G
0
Vth
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CMOS( 互補金氧半 ) Logic
P 型網路
N 型網路
FX
1. P 型網路為 F(X) 的 Relay logic
2. N 型網路為 F(X) 的 Relay logicAND 與 OR 互換即可
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Stick Diagram1. 常用佈局表示法及簡化佈局法
1. 格子 (Grid) 狀文字 (Font) 表示法2. EDIF 為一種 ( 層次,對角座標 ) 的表示法3. Stick diagram: 草圖用,將不重要寬度省略
2. 例:
2/0.35
1/0.35
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例如: F=(A+B)(C+D)
因為 F=(A+B)(C+D)
N 型網路為: A B
C D
P 型網路為:
因為 F= A B + C D A
B
C
D
A B
C D
A
B
C
D
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尤拉路徑 (Euler Path)
1. 十八世紀拓樸學被用來簡化 CMOS 邏輯閘佈局
2. N 型路徑為 N 型 Relay-logic 網路3. P 型路徑為 P 型 Relay-logic 網路4.拓樸學證明各輸入開關 X 與 X 交叉通過!
BA
F
S
FD
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BA
尤拉路徑 (Euler Path) 佈局法
先畫出一倍寬度的 N+IMP
再畫出兩倍寬度的 P+IMP
VSS
VDD
BA
F
S
FD
S A F B S
D A B F
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FVdd
例如: F=(A+B)(C+D)
A B
C D
N
F
Vss
F A N C Vss D N B F
X A Vdd C D F B XX
A C D B
F
選擇路徑時,輸入要有相同的順序重遇點或切斷點均須命名!
標準邏輯元件, Stancard Cell通常等高,兩上下兩邊作
通道繞線 (Channel Routing)
A C B D F
Vss
Vdd Vdd
Vss
A C B D F
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Cell-Based Channel Routing
NANDNANDNOTAOINOTXORNORNAND
NANDNANDNOTAOI NOTXORNORNAND
NANDNAND NOTAOI NOTXORNORNAND
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Primitive Gates1. Primitive: A- -tomic (Cannot be cut off)
2. Properties of a CMOS Primitives:
• Either pulled up or pulled down;
• Current from or to the single output
• IDDQ=0 for Ideal CMOS
3. Usual Symbols:
• directly assembled without wire.
• {AND, OR} Combo ended with an Inverter
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Complex PrimitiveTrivial Example
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Usual Example and Naming
OAI231
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Switch Intention
S
D
G
0
0
D
S
G
1
1
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Pass Transistor as Switch
S D
G
DS
G
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Pass Transistor as Switch
1. Good p/n switch for 1/0 but bad for 0/1
2. CMOS Transmission gate – another compensated structure
3. Pass Transistor Logic (PTL)
1. VDD >> stages * Vth
2. Pulled-up or down
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Transmission Gate
BA
C
C
C
C
BA
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Tri-State
0
1
IN
High ImpedianceFloating (connection)
Hi-Z‘z’
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Tri-State Logic
AND 0 Z 1
0 0 0 0
Z 0 Z Z
1 0 Z 1
OR 0 Z 1
0 0 Z 1
Z Z Z 1
1 1 1 1
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2-to-1 Multiplexer
0
1
A
B
C
AC+BC
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TG-based Multiplexer
C
C
A
C
C
B
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TG-based Multiplexer
Bidirectional
No tri-state in ideal timing
Bus Contention possibly !
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Memory – Latches and Registers Prior to ’90s, they’re used to be confused. Latch: Level Sensitive Register: Edge Triggled 50’s Flipflop (Very slow frequency):
Later Flipflop:
Latch
LatchLatch
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Static Gate Based Latch
Example: Resettable D Latch
D
D
CLK
Q
D
D
CLK
QRESET
(a) (b) (c) (d)
D
D
Q
Q
R
CLK
D
D
Q
Q
R
CLK
QQ222 221
RESET
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Switch-Based Static Latch and Flipflop
D
CLK
Q
SkewSkew
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Home #1
1. Draw all 6-input AOI gates in structured style
2. Draw all possible structured stick diagrams of a primitive OAI32 using Eular-Paths
3. Thinking or Reading: 4-T XOR gate design; Write your afterthoughts in hundreds words.
Due: Oct. 27, 2003
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Preparation for Next Lecture
1. Prepare at least one SPICE-like tool (e.g., download the ORCAD/Design Lab 8.0 freeware)
2. Try to install and excise some simple example