
DATA SH EET
Product specification 
File under Integrated Circuits, IC06
December 1990
INTEGRATED CIRCUITS
74HC/HCT240
Octal buffer/line driver; 3-state; 
inverting
For a complete data sheet, please also download:
•The IC06 74HC/HCT/HCU/HCMOS Logic Family Specifications
•The IC06 74HC/HCT/HCU/HCMOS Logic Package Information
•The IC06 74HC/HCT/HCU/HCMOS Logic Package Outlines
 

December 1990 2
Philips Semiconductors Product specification
Octal buffer/line driver; 3-state; 
inverting
74HC/HCT240
FEATURES
• Output capability: bus driver
• ICC category: MSI
GENERAL DESCRIPTION
The 74HC/HCT240 are high-speed Si-gate CMOS devices 
and are pin compatible with low power Schottky TTL 
(LSTTL). They are specified in compliance with JEDEC 
standard no. 7A.
The 74HC/HCT240 are octal inverting buffer/line drivers 
with 3-state outputs. The 3-state outputs are controlled by 
the output enable inputs 1OE and 2OE. A HIGH on nOE 
causes the outputs to assume a high impedance 
OFF-state. The “240” is identical to the “244” but has 
inverting outputs.
QUICK REFERENCE DATA
GND = 0 V; T
amb
=25°C; tr=tf= 6 ns
Notes
1. C
PD
 is used to determine the dynamic power dissipation (PD in µW):
PD=CPD× V
CC
2
× fi+ ∑ (CL× V
CC
2
 × fo) where: 
fi= input frequency in MHz 
fo= output frequency in MHz 
∑ (CL× V
CC
2
× fo) = sum of outputs 
CL= output load capacitance in pF 
VCC= supply voltage in V
2. For HC the condition is VI= GND to V
CC
For HCT the condition is VI= GND to VCC− 1.5 V
ORDERING INFORMATION
See
“74HC/HCT/HCU/HCMOS Logic Package Information”
.
SYMBOL PARAMETER CONDITIONS
TYPICAL
UNIT
HC HCT
t
PHL/ tPLH
propagation delay
1An to 1Yn; 
2An to 2Y
n
CL= 15 pF; VCC=5 V99ns
C
I
input capacitance 3.5 3.5 pF
C
PD
power dissipation capacitance per buffer notes 1 and 2 30 30 pF
 

December 1990 3
Philips Semiconductors Product specification
Octal buffer/line driver; 3-state; inverting 74HC/HCT240
PIN DESCRIPTION
PIN NO. SYMBOL NAME AND FUNCTION
11
OE output enable input (active LOW)
2, 4, 6, 8 1A
0
 to 1A
3
data inputs
3, 5, 7, 9 2Y
0
 to 2Y
3
bus outputs 
10 GND ground (0 V) 
17, 15, 13, 11 2A
0
 to 2A
3
data inputs 
18, 16, 14, 12 1Y
0
 to 1Y
3
bus outputs 
19 2
OE output enable input (active LOW)
20 V
CC
positive supply voltage
Fig.1 Pin configuration. Fig.2 Logic symbol. Fig.3 IEC logic symbol.
 

December 1990 4
Philips Semiconductors Product specification
Octal buffer/line driver; 3-state; inverting 74HC/HCT240
Fig.4 Functional diagram.
FUNCTION TABLE
Notes
1. H = HIGH voltage level 
L = LOW voltage level 
X = don’t care 
Z = high impedance OFF-state
INPUTS OUTPUT
n
OE nA
n
nY
n
L 
L 
H
L 
H 
X
H
L
Z
 

December 1990 5
Philips Semiconductors Product specification
Octal buffer/line driver; 3-state; inverting 74HC/HCT240
DC CHARACTERISTICS FOR 74HC
For the DC characteristics see
“74HC/HCT/HCU/HCMOS Logic Family Specifications”
.
Output capability: bus driver 
ICC category: MSI
AC CHARACTERISTICS FOR 74HC
GND = 0 V; t
r=tf
= 6 ns; CL= 50 pF
SYMBOL PARAMETER
T
amb
 (°C) TEST CONDITIONS
74HC
V
CC
(V)
WAVEFORMS
+25 −40 to +85 −40 to +125
min.
typ. max. min. max. min. max.
t
PHL
/ t
PLH
propagation delay
1An to 1Yn; 
2An to 2Y
n
30 
11 
9
100 
20 
17
125 
25 
21
150 
30 
26
ns 2.0
4.5
6.0
Fig.5
t
PZH
/ t
PZL
3-state output enable time
1OE to 1Yn; 
2OE to 2Y
n
39 
14 
11
150 
30 
26
190 
38 
33
225 
45 
38
ns 2.0
4.5
6.0
Fig.6
t
PHZ
/ t
PLZ
3-state output disable time
1OE to 1Yn; 
2OE to 2Y
n
41 
15 
12
150 
30 
26
190 
38 
33
225 
45 
38
ns 2.0
4.5
6.0
Fig.6
t
THL
/ t
TLH
output transition time 14
5 
4
60 
12 
10
75 
15 
13
90 
18 
15
ns 2.0
4.5
6.0
Fig.5
 

December 1990 6
Philips Semiconductors Product specification
Octal buffer/line driver; 3-state; inverting 74HC/HCT240
DC CHARACTERISTICS FOR 74HCT
For the DC characteristics see
“74HC/HCT/HCU/HCMOS Logic Family Specifications”
.
Output capability: bus driver 
IICC 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 ∆ICC per input, multiply this value by the unit load coefficient shown in the table below.
AC CHARACTERISTICS FOR 74HCT
GND = 0 V; tr=tf= 6 ns; CL= 50 pF
INPUT UNIT LOAD COEFFICIENT
1A
n
2A
n
1OE 
2OE
1.50
1.50
0.70
0.70
SYMBOL PARAMETER
T
amb
 (°C) TEST CONDITIONS
74HCT
UNIT
V
CC
(V)
WAVEFORMS
+25 −40 to +85 −40 to +125
min. typ. max. min. max. min. max.
t
PHL
/ t
PLH
propagation delay
1An to 1Yn; 
2An to 2Y
n
11 20 25 30 ns 4.5 Fig.5
t
PZH
/ t
PZL
3-state output enable time
1OE to 1Yn; 
2OE to 2Y
n
13 30 38 45 ns 4.5 Fig.6
t
PHZ
/ t
PLZ
3-state output disable time
1OE to 1Yn; 
2OE to 2Y
n
13 25 31 38 ns 4.5 Fig.6
t
THL
/ t
TLH
output transition time 5 12 15 18 ns 4.5 Fig.5
 

December 1990 7
Philips Semiconductors Product specification
Octal buffer/line driver; 3-state; inverting 74HC/HCT240
AC WAVEFORMS
PACKAGE OUTLINES
See
“74HC/HCT/HCU/HCMOS Logic Package Outlines”
.
Fig.5 Waveforms showing the input (1An, 2An) to output (1Yn, 2Yn) propagation delays and the output transition
times.
(1) HC : VM= 50%; VI= GND to VCC.
HCT: VM= 1.3 V; VI= GND to 3 V.
Fig.6 Waveforms showing the 3-state enable and disable times.
(1) HC : VM= 50%; VI= GND to VCC.
HCT: VM= 1.3 V; VI= GND to 3 V.