December 1990 6
Philips Semiconductors Product specification
8-input multiplexer; 3-state 74HC/HCT251
DC CHARACTERISTICS FOR 74HCT
For the DC characteristics see
“74HC/HCT/HCU/HCMOS Logic Family Specifications”
.
Output capability: standard
I
CC
category: MSI
Note to HCT types
The value of additional quiescent supply current (∆I
CC
) for a unit load of 1 is given in the family specifications.
To determine ∆I
CC
per input, multiply this value by the unit load coefficient shown in the table below.
AC CHARACTERISTICS FOR HCT
GND = 0 V; t
r
= t
f
= 6 ns; C
L
= 50 pF
INPUT UNIT LOAD COEFFICIENT
I
n
S
0
S
1
,S
2
OE
1.00
1.50
1.50
1.50
SYMBOL PARAMETER
T
amb
(°C)
UNIT
TEST CONDITIONS
74HCT
V
CC
(V)
WAVEFORMS
+25 −40 to +85 −40 to +125
min. typ. max. min. max. min. max.
t
PHL
/ t
PLH
propagation delay
I
n
to Y
22 35 44 53 ns 4.5 Fig.6
t
PHL
/ t
PLH
propagation delay
I
n
to Y
22 35 44 53 ns 4.5 Fig.7
t
PHL
/ t
PLH
propagation delay
S
n
to Y
24 44 55 66 ns 4.5 Fig.6
t
PHL
/ t
PLH
propagation delay
S
n
to Y
25 44 55 66 ns 4.5 Fig.7
t
PZH
/ t
PZL
3-state output enable time
OE to Y, Y
13 28 35 42 ns 4.5 Fig.7
t
PHZ
/ t
PLZ
3-state output disable time
OE to Y, Y
14 28 35 42 ns 4.5 Fig.7
t
THL
/ t
TLH
output transition time 7 15 19 22 ns 4.5 Figs 6 and 7
