1/9
June 2001
s
HIGH SPEED: t
PD
= 5.4 ns (TYP.) at V
CC
= 5V
s
LOW POWER DISSIPATION:
I
CC
= 4
A (MAX.) at T
A
=25C
s
COMPATIBLE WITH TTL OUTPUTS:
V
IH
= 2V (MIN.), V
IL
= 0.8V (MAX)
s
POWER DOWN PROTECTION ON INPUTS
& OUTPUTS
s
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 8 mA (MIN)
s
BALANCED PROPAGATION DELAYS:
t
PLH
t
PHL
s
OPERATING VOLTAGE RANGE:
V
CC
(OPR) = 4.5V to 5.5V
s
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 240
s
IMPROVED LATCH-UP IMMUNITY
s
LOW NOISE: V
OLP
= 0.9V (MAX.)
DESCRIPTION
The 74VHCT240A is an advanced high-speed
CMOS OCTAL BUS BUFFER (3-STATE)
fabricated with sub-micron silicon gate and
double-layer metal wiring C
2
MOS technology.
G enable input governs four BUS BUFFERs.
This device is designed to be used with 3 state
memory address drivers, etc.
Power down protection is provided on all inputs
and outputs and 0 to 7V can be accepted on
inputs with no regard to the supply voltage. This
device can be used to interface 5V to 3V since all
inputs are equipped with TTL threshold.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
74VHCT240A
OCTAL BUS BUFFER
WITH 3 STATE OUTPUTS (INVERTED)
PIN CONNECTION AND IEC LOGIC SYMBOLS
ORDER CODES
PACKAGE
TUBE
T & R
SOP
74VHCT240AM
74VHCT240AMTR
TSSOP
74VHCT240ATTR
TSSOP
SOP
74VHCT240A
2/9
INPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
TRUTH TABLE
X: Don`t Care
Z : High Impedance
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
1) Output in OFF State
2) High or Low State
PIN No
SYMBOL
NAME AND FUNCTION
1
1G
Output Enable Input
2, 4, 6, 8
1A1 to 1A4
Data Inputs
9, 7, 5, 3
2Y1 to 2Y4
Data Outputs
11, 13, 15,
17
2A1 to 2A4
Data Inputs
18, 16, 14,
12
1Y1 to 1Y4
Data Outputs
19
2G
Output Enable Input
10
GND
Ground (0V)
20
V
CC
Positive Supply Voltage
INPUTS
OUTPUT
G
An
Yn
L
L
H
L
H
L
H
X
Z
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
-0.5 to +7.0
V
V
I
DC Input Voltage
-0.5 to +7.0
V
V
O
DC Output Voltage (see note 1)
-0.5 to +7.0
V
V
O
DC Output Voltage (see note 2)
-0.5 to V
CC
+ 0.5
V
I
IK
DC Input Diode Current
- 20
mA
I
OK
DC Output Diode Current
20
mA
I
O
DC Output Current
25
mA
I
CC
or I
GND
DC V
CC
or Ground Current
50
mA
T
stg
Storage Temperature
-65 to +150
C
T
L
Lead Temperature (10 sec)
300
C
74VHCT240A
3/9
RECOMMENDED OPERATING CONDITIONS
1) Output in OFF State
2) High or Low State
3) VIN from 0.8V to 2V
DC SPECIFICATIONS
AC ELECTRICAL CHARACTERISTICS (Input t
r
= t
f
= 3ns)
(*) Voltage range is 5.0V
0.5V
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
4.5 to 5.5
V
V
I
Input Voltage
0 to 5.5
V
V
O
Output Voltage (see note 1)
0 to 5.5
V
V
O
Output Voltage (see note 2)
0 to V
CC
V
T
op
Operating Temperature
-55 to 125
C
dt/dv
Input Rise and Fall Time (see note 3) (V
CC
= 5.0
0.5V)
0 to 20
ns/V
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
V
IH
High Level Input
Voltage
4.5 to
5.5
2
2
2
V
V
IL
Low Level Input
Voltage
4.5 to
5.5
0.8
0.8
0.8
V
V
OH
High Level Output
Voltage
4.5
I
O
=-50
A
4.4
4.5
4.4
4.4
V
4.5
I
O
=-8 mA
3.94
3.8
3.7
V
OL
Low Level Output
Voltage
4.5
I
O
=50
A
0.0
0.1
0.1
0.1
V
4.5
I
O
=8 mA
0.36
0.44
0.55
Ioz
High Impedance
Output Leakage
Current
4.5 to
5.5
V
I
= V
IH
or V
IL
V
O
= 0V to 5.5V
0.25
2.5
2.5
A
I
I
Input Leakage
Current
0 to
5.5
V
I
= 5.5V or GND
0.1
1.0
1.0
A
I
CC
Quiescent Supply
Current
5.5
V
I
= V
CC
or GND
4
40
40
A
I
CC
Additional Worst
Case Supply
Current
5.5
One Input at 3.4V,
other input at V
CC
or GND
1.35
1.5
1.5
mA
I
OPD
Output Leakage
Current
0
V
OUT
= 5.5V
0.5
5.0
5.0
A
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(*)
(V)
C
L
(pF)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
t
PLH
t
PHL
Propagation Delay
Time
5.0
15
5.4
7.4
1.0
8.5
1.0
8.5
ns
5.0
50
5.9
8.4
1.0
9.5
1.0
9.5
t
PLZ
t
PHZ
Output Disable
Time
5.0
15
RL = 1K
8.3
10.4
1.0
12.0
1.0
12.0
ns
5.0
50
8.8
11.4
1.0
13.0
1.0
13.0
t
PZL
t
PZH
Output Enable
Time
5.0
50
RL = 1K
8.2
11.4
1.0
13.0
1.0
13.0
ns
74VHCT240A
4/9
CAPACITIVE CHARACTERISTICS
1) C
PD
is defined as the value of the IC's internal equivalent capacitance which is calculated from the operating current consumption without
load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. I
CC(opr)
= C
PD
x V
CC
x f
IN
+ I
CC
/8 (per
Circuit)
DYNAMIC SWITCHING CHARACTERISTICS
1) Worst case package.
2) Max number of outputs defined as (n). Data inputs are driven 0V to 3.0V, (n-1) outputs switching and one output at GND.
3) Max number of data inputs (n) switching. (n-1) switching 0V to 3.0V. Inputs under test switching: 3.0V to threshold (V
ILD
), 0V to threshold
(V
IHD
), f=1MHz.
Symbol
Parameter
Test Condition
Value
Unit
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
C
IN
Input Capacitance
6
10
10
10
pF
C
OUT
Output
Capacitance
9
pF
C
PD
Power Dissipation
Capacitance
(note 1)
19
pF
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
V
OLP
Dynamic Low
Voltage Quiet
Output (note 1, 2)
5.0
C
L
= 50 pF
0.9
1.1
V
V
OLV
1.1
-0.9
V
IHD
Dynamic High
Voltage Input
(note 1, 3)
5.0
2.0
V
ILD
Dynamic Low
Voltage Input
(note 1, 3)
5.0
0.8
74VHCT240A
5/9
TEST CIRCUIT
C
L
=15/ 50pF or equivalent (includes jig and probe capacitance)
R
L
= R
1
= 1K
or equivalent
R
T
= Z
OUT
of pulse generator (typically 50
)
WAVEFORM 1 : PROPAGATION DELAYS (f=1MHz; 50% duty cycle)
TEST
SWITCH
t
PLH
, t
PHL
Open
t
PZL
, t
PLZ
V
CC
t
PZH
, t
PHZ
GND
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