Datasheet

December 1990 6
Philips Semiconductors Product specification
Octal Schmitt trigger buffer/line driver; 3-state 74HC/HCT7541
DC CHARACTERISTICS FOR 74HCT
For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications” .
Transfer characteristics are given below (not applicable for OE
n
inputs).
Output capability: bus driver
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 74HCT
GND = 0 V; t
r
=t
f
= 6 ns; C
L
= 50 pF
TRANSFER CHARACTERISTICS FOR 74HCT
Voltages are referred to GND (ground = 0 V)
INPUT UNIT LOAD COEFFICIENT
OE
1
OE
2
A
n
1.30
1.30
0.20
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
A
n
to Y
n
19 32 40 48 ns 4.5 Fig.8
t
PZH
/ t
PZL
3-state output enable time
OE
n
to Y
n
18 32 40 48 ns 4.5 Fig.8
t
PHZ
/ t
PLZ
3-state output disable time
OE
n
to Y
n
20 32 40 48 ns 4.5 Fig.8
t
THL
/ t
TLH
output transition time 5 12 15 18 ns 4.5 Fig.8
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.
V
T+
positive-going threshold 2.0
2.1
2.0
2.1
2.0
2.1
V 4.5
5.5
Figs 6 and 7
V
T−
negative-going threshold 0.70
0.80
0.64
0.74
0.60
0.70
V 4.5
5.5
Figs 6 and 7
V
H
hysteresis (V
T+
− V
T−
) 0.17
0.17
0.23
0.23
V 4.5
5.5
Figs 6 and 7