
4-39
FAST AND LS TTL DATA
MC54/74F85
AC ELECTRICAL CHARACTERISTICS
54/74F
54F
74F
TA = +25
°
C
VCC = +5.0 V
CL = 50 pF
TA = –55
°
C to +125
°
C
VCC = 5.0 V
±
10%
CL = 50 pF
TA = 0
°
C to + 70
°
C
VCC = 5.0 V
±
10%
CL = 50 pF
Symbol
Parameter
Min
Max
Min
Max
Min
Max
Unit
tPLH
tPHL
tPLH
tPHL
tPLH
A or B Input to
6.0
11
5.5
14
5.5
13
ns
A < B, A > B Output
6.0
14
5.5
16.5
5.5
15.5
A or B Input to
5.5
11.5
5.0
15
5.0
14
ns
A = B Output
7.0
14
6.5
15.5
6.5
14.5
IA<B and IA=B Input
3.0
7.5
2.5
10
2.5
9.0
ns
tPHL
tPLH
tPHL
tPLH
tPHL
to A>B Output
3.0
9.0
2.5
11
2.5
10
IA=B Input to
A = B Output
2.5
7.0
2.0
10
2.0
9.0
ns
3.5
10
2.5
13
2.5
12
IA>B and IA=B Input
to A<B Output
3.0
8.0
3.0
10.5
3.0
9.5
ns
3.0
9.0
2.0
10.5
2.0
9.5
The expansion inputs IA>B, IA=B, and IA<B are the least sig-
nificant bit positions. When used for series expansion, the
A>B, A=B, and A<B outputs of the least significant word are
connected to the corresponding IA>B, IA=B, and IA<B nputs of
the next higher stage. Stages can be added in this manner
to any length, but a propagation delay penalty of about 15 ns
is added with each additional stage. For proper operation the
expansion inputs of the least significant word should be tied
as follows: IA>B = LOW, IA=B = HIGH, and IA<B = LOW.
IA < B
IA = B
IA > B
NOTE:
This diagram is provided only for the understanding of logic operations and should not be used
to estimate propagation delays.
Figure 2. Logic Diagram
(15)
(1)
A3
B3
A2
B2
(13)
(14)
(2)
(3)
A1
B1
(12)
(11)
(4)
(5)
(6)
(7)
A > B
A = B
A < B
A0
B0
(10)
(9)