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
ICC category: MSI
Note to HCT types
The value of additional quiescent supply current (∆ICC) for a unit load of 1 is given in the family specifications.
To determine ∆ICC per input, multiply this value by the unit load coefficient shown in the table below.
INPUT
UNIT LOAD COEFFICIENT
In
S0
S1, S2
OE
1.00
1.50
1.50
1.50
AC CHARACTERISTICS FOR HCT
GND = 0 V; tr = tf = 6 ns; CL = 50 pF
Tamb (°C)
TEST CONDITIONS
74HCT
SYMBOL PARAMETER
UNIT
WAVEFORMS
VCC
(V)
+25
−40 to +85 −40 to +125
min. typ. max. min. max. min. max.
tPHL/ tPLH propagation delay
In to Y
22
22
24
25
13
14
7
35
35
44
44
28
28
15
44
44
55
55
35
35
19
53
53
66
66
42
42
22
ns
ns
ns
ns
ns
ns
ns
4.5 Fig.6
4.5 Fig.7
4.5 Fig.6
4.5 Fig.7
4.5 Fig.7
4.5 Fig.7
4.5 Figs 6 and 7
t
t
t
PHL/ tPLH propagation delay
In to Y
PHL/ tPLH propagation delay
Sn to Y
PHL/ tPLH propagation delay
Sn to Y
tPZH/ tPZL 3-state output enable time
OE to Y, Y
tPHZ/ tPLZ 3-state output disable time
OE to Y, Y
t
THL/ tTLH output transition time
December 1990
6
NXP [ NXP ]
