Chapter 2 Function Block
4-Bit Look Ahead Carry Generator
Chapter 2 Function Block
Switching speed
Function
Block
type
Input
Output
Path
→
t LD0 (ns)
t 1
Standard type
Block type
IN
X0
OUT
MIN.
TYP. MAX.
MIN.
0.015
0.021
0.010
0.029
0.010
0.011
0.011
0.011
0.015
0.016
0.010
0.029
0.010
0.011
0.011
0.015
0.010
0.029
0.010
0.011
0.011
0.015
0.011
0.011
0.010
0.029
0.010
0.011
0.011
0.015
0.010
0.011
0.011
0.015
0.011
0.011
0.010
0.011
0.011
0.015
0.011
0.015
0.011
0.011
0.011
0.015
0.021
0.015
0.029
0.010
0.011
0.010
TYP. MAX. Symbol Fanin Symbol Fanout
Normal
High speed
(HL) 0.129
(LH) 0.148
(HL) 0.336
(LH) 0.241
(HL) 0.557
(LH) 0.516
(HH) 0.142
0.196
0.229
0.542
0.423
0.976
0.910
0.221
0.521
0.262
0.248
0.565
0.465
0.920
0.754
0.840
0.616
0.419
0.383
0.585
0.500
0.541
0.436
0.241
0.580
0.559
0.497
0.932
0.792
0.906
0.587
0.613
0.507
0.506
0.465
0.257
0.703
1.076
0.941
0.947
0.653
0.518
0.461
0.257
0.715
0.937
0.669
0.415
0.370
0.659
0.676
0.837
0.746
0.361
0.361
1.094
0.791
2.329
1.732
0.353
0.807
0.575
0.477
1.118
0.933
2.391
1.511
2.183
1.325
0.747
0.683
1.278
1.034
1.146
0.769
0.395
1.051
1.121
0.951
2.386
1.535
2.352
1.209
1.342
1.134
1.138
0.953
0.419
1.430
2.521
1.672
2.388
1.269
1.167
1.039
0.414
1.491
2.379
1.282
0.744
0.747
1.199
1.336
1.359
1.476
0.020
0.029
0.013
0.041
0.012
0.015
0.015
0.015
0.020
0.023
0.013
0.041
0.012
0.015
0.016
0.021
0.013
0.041
0.012
0.015
0.016
0.021
0.015
0.015
0.013
0.041
0.012
0.015
0.016
0.021
0.012
0.015
0.016
0.021
0.015
0.015
0.012
0.015
0.016
0.021
0.015
0.021
0.015
0.015
0.016
0.021
0.029
0.020
0.041
0.013
0.015
0.012
0.031
0.041
0.018
0.059
0.017
0.022
0.021
0.022
0.031
0.032
0.018
0.059
0.017
0.022
0.025
0.033
0.017
0.059
0.017
0.022
0.023
0.033
0.021
0.022
0.018
0.059
0.017
0.022
0.025
0.033
0.017
0.022
0.023
0.033
0.022
0.022
0.017
0.022
0.025
0.033
0.022
0.032
0.022
0.022
0.025
0.032
0.041
0.031
0.059
0.018
0.022
0.017
X0
Y0
X1
Y1
X2
Y2
X3
Y3
CNB
7.1
10.9
5.4
9.1
3.9
7.7
2.8
4.3
2.1
CN+XB
CN+YB
CN+ZB
Y
11
10
34
22
34
F526
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→
CN+XB
Drivability
Name cells
Name cells
X0
X0
CN+YB
CN+ZB
X
Low Power
x1
x2
x4
F526
34
X
X0
(LL)
0.348
(HL) 0.126
(LH) 0.103
(HL) 0.317
(LH) 0.255
(HL) 0.347
(LH) 0.300
(HH) 0.453
Y0
CN+XB
CN+YB
CN+ZB
Y
Logic Diagram
Y0
Y3 H08
X3 H07
Y2 H06
X2 H05
Y1 H04
X1 H03
Y0 H02
X0 H01
CNB H09
N05
N04
X
Y
Y0
Y0
(LL)
0.329
N03 CN+ZB
N02 CN+YB
N01 CN+XB
(HL) 0.267
(LH) 0.226
(HL) 0.345
(LH) 0.289
(HH) 0.331
X1
CN+YB
CN+ZB
Y
X1
X1
(LL)
(HH) 0.156
(LL) 0.364
0.275
X1
X
(HL) 0.241
(LH) 0.242
(HL) 0.305
(LH) 0.254
(HH) 0.319
Y1
CN+YB
CN+ZB
Y
Y1
Y1
Truth Table
(LL)
0.251
Y3
Y2
Y1
Y0
X3
X2
X1
Y
Y0
X0 CnB
Cn+xB
(HL) 0.366
(LH) 0.276
(HH) 0.300
X2
CN+ZB
Y
0
X
X
X
X
0
X
X
0
X
X
X
0
X
0
0
0
X
X
0
0
X
X
X
0
0
0
0
0
1
0
X
0
X
1
1
1
0
X2
X
(LL)
(HH) 0.167
(LL) 0.390
0.270
X
X
All other combinations
X2
X
X
All other combinations
(HL) 0.316
(LH) 0.321
(HH) 0.288
X3
0
X2
0
X1
0
X0
X
Y2
CN+ZB
Y
0
0
1
Y2
Y2
Y1
Y0
X2
X1
X0 CnB Cn+zB
All other combinations
(LL)
(HH) 0.309
(LL) 0.252
(HH) 0.168
(LL) 0.387
(HH) 0.278
(LL) 0.294
(HH) 0.252
0.292
0
X
X
X
X
0
X
X
0
X
0
0
0
X
X
0
0
X
X
X
0
X
X
X
1
1
1
1
1
0
X3
Y
X
X
X3
X
X
Y3
Y
All other combinations
CNB
CNB
CNB
CN+XB
CN+YB
CN+ZB
Y1
Y0 X1
X0 CnB Cn+yB
(LL)
(HH) 0.399
(LL) 0.403
(HH) 0.537
(LL) 0.443
0.224
0
X
X
X
0
X
0
0
X
X
0
X
X
1
1
1
1
0
X
All other combinations
F526
Block Library A13872EJ5V0BL
2 - 192
Block Library A13872EJ5V0BL
2 - 193
ETC [ ETC ]
