Data Sheet

www.fairchildsemi.com 4
74VHC138
AC Electrical Characteristics
Note 3: C
PD
is defined as the value of the internal equivalent capacitance which is calculated from the operating current consumption without load. Average
operating current can be obtained by the equation: I
CC
(opr.) = C
PD
* V
CC
* f
IN
+ I
CC
.
Symbol Parameter
V
CC
(V)
T
A
= 25°CT
A
= −40°C to +85°C
Units Conditions
Min Typ Max Min Max
t
PLH
Propagation Delay 3.3 ± 0.3 8.2 11.4 1.0 13.5
ns
C
L
= 15 pF
t
PHL
A
n
to O
n
10.0 15.8 1.0 18.0 C
L
= 50 pF
5.0 ± 0.5 5.7 8.1 1.0 9.5
ns
C
L
= 15 pF
7.2 10.1 1.0 11.5 C
L
= 50 pF
t
PLH
Propagation Delay 3.3 ± 0.3 8.1 12.8 1.0 15.0
ns
C
L
= 15 pF
t
PHL
E
3
to O
n
10.6 16.3 1.0 18.5 C
L
= 50 pF
5.0 ± 0.5 5.6 8.1 1.0 9.5
ns
C
L
= 15 pF
7.1 10.1 1.0 11.5 C
L
= 50 pF
t
PLH
Propagation Delay 3.3 ± 0.3 8.2 11.4 1.0 13.5
ns
C
L
= 15 pF
t
PHL
E
1
or E
2
to O
n
10.7 14.9 1.0 17.0 C
L
= 50 pF
5.0 ± 0.5 5.8 8.1 1.0 9.5
ns
C
L
= 15 pF
7.3 10.1 1.0 11.5 C
L
= 50 pF
C
IN
Input Capacitance 4 10 10 pF V
CC
= Open
C
PD
Power Dissipation 34 pF (Note 3)
Capacitance