74VHC244
®
OCTAL BUS BUFFER
WITH 3 STATE OUTPUTS (NON INVERTED)
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HIGH SPEED: tPD = 3.9 ns (TYP.) at VCC = 5V
LOW POWER DISSIPATION:
ICC = 4 µA (MAX.) at TA = 25 oC
HIGH NOISE IMMUNITY:
VNIH = VNIL = 28% VCC (MIN.)
POWER DOWN PROTECTION ON INPUTS
SYMMETRICAL OUTPUT IMPEDANCE:
|IOH| = IOL = 8 mA (MIN)
BALANCED PROPAGATION DELAYS:
tPLH ≅ tPHL
OPERATING VOLTAGE RANGE:
VCC (OPR) = 2V to 5.5V
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 244
IMPROVED LATCH-UP IMMUNITY
LOW NOISE VOLP = 0.9V (Max.)
DESCRIPTION
The 74VHC244 is an advanced high speed
CMOS OCTAL BUS BUFFER (3-STATE)
fabricated with sub-micron silicon gate and
double-layer metal wiring C2MOS technology.
G output enable governs four BUS BUFFERs.
M
(Micro Package)
T
(TSSOP Package)
ORDER CODES :
74VHC244M
74VHC244T
This device is designed to be used with 3 state
memory address drivers, etc.
Power down protection is provided on all inputs
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.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
PIN CONNECTION AND IEC LOGIC SYMBOLS
June 1999
1/8
74VHC244
INPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
PIN No
SYMBOL
1
1G
NAME AND FUNCTION
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
Output Enable Input
19
2G
10
GND
Ground (0V)
20
VCC
Positive Supply Voltage
Output Enable Input
TRUTH TABLE
INPUT
G
OUTPUT
An
Yn
L
L
L
L
H
H
X
H
Z
X: "H" or "L"
Z: High impedance
ABSOLUTE MAXIMUM RATINGS
Symbol
VCC
Parameter
Supply Voltage
VI
DC Input Voltage
VO
DC Output Voltage
Value
Unit
-0.5 to +7.0
V
-0.5 to +7.0
V
-0.5 to VCC + 0.5
V
IIK
DC Input Diode Current
- 20
mA
IOK
DC Output Diode Current
± 20
mA
IO
DC Output Current
± 25
mA
DC VCC or Ground Current
± 75
mA
ICC or IGND
Tstg
TL
Storage Temperature
Lead Temperature (10 sec)
-65 to +150
o
300
o
C
C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied.
RECOMMENDED OPERATING CONDITIONS
Symbol
VCC
Parameter
Supply Voltage
Unit
V
V
VI
Input Voltage
0 to 5.5
VO
Output Voltage
0 to VCC
Top
dt/dv
Operating Temperature
Input Rise and Fall Time (see note 1) (VCC = 3.3 ± 0.3V)
(VCC = 5.0 ± 0.5V)
1) VIN from 30% to 70% of VCC
2/8
Value
2.0 to 5.5
-40 to +85
0 to 100
0 to 20
V
o
C
ns/V
ns/V
74VHC244
DC SPECIFICATIONS
Symbol
VIH
VIL
VOH
VOL
IOZ
II
ICC
Parameter
Test Conditions
Value
T A = 25 o C
V CC
(V)
Min.
Typ.
Unit
-40 to 85 o C
Max.
Min.
High Level Input
Voltage
2.0
1.5
1.5
3.0 to 5.5
0.7VCC
0.7VCC
Low Level Input
Voltage
2.0
0.5
3.0 to 5.5
0.3VCC
High Level Output
Voltage
Low Level Output
Voltage
High Impedance
Output Leakage
Current
Input Leakage Current
Quiescent Supply
Current
Max.
V
0.5
0.3VCC
V
2.0
IO=-50 µA
1.9
2.0
1.9
3.0
IO=-50 µA
IO=-50 µA
2.9
3.0
2.9
4.5
4.4
4.5
4.4
3.0
4.5
IO=-4 mA
IO=-8 mA
2.58
3.94
2.0
IO=50 µA
0.0
0.1
0.1
3.0
IO=50 µA
0.0
0.1
0.1
4.5
IO=50 µA
0.0
0.1
0.1
3.0
4.5
IO=4 mA
IO=8 mA
0.36
0.36
0.44
0.44
VI = VIH or VIL
VO = VCC or GND
±0.25
±2.5
5.5
0 to 5.5
VI = 5.5V or GND
±0.1
±1.0
µA
5.5
VI = VCC or GND
4
40
µA
V
2.48
3.8
V
µA
AC ELECTRICAL CHARACTERISTICS (Input tr = tf =3 ns)
Symbol
Parameter
V CC
(V)
tPLH
tPHL
Propagation Delay
Time
tPZL
tPZH
Output Enable Time
tPLZ
tPHZ
Output Disable Time
tOSLH
tOSHL
Output to Output Skew
Time (note 1)
Test Condition
CL
(pF)
3.3(*)
3.3(*)
5.0(**)
5.0(**)
3.3(*)
3.3(*)
5.0(**)
5.0(**)
3.3(*)
5.0(**)
3.3(*)
5.0(**)
15
50
15
50
15
50
15
50
50
50
50
50
RL = 1KΩ
RL = 1KΩ
RL = 1KΩ
RL = 1KΩ
RL = 1KΩ
RL = 1KΩ
Value
T A = 25 o C
Min. Typ. Max.
5.8
8.4
8.3
11.9
3.9
5.5
5.4
7.5
6.6
10.6
9.1
14.1
4.7
7.3
6.2
9.3
10.3
14.0
6.7
9.2
1.5
1.0
Unit
-40 to 85 o C
Min. Max.
1.0
10.0
1.0
13.5
1.0
6.5
1.0
8.5
1.0
12.5
1.0
16.0
1.0
8.5
1.0
10.5
1.0
16.0
1.0
10.5
1.5
1.0
ns
ns
ns
ns
(*) Voltage range is 3.3V ± 0.3V
(**) Voltage range is 5V ± 0.5V
Note 1: Parameter guaranteed by design. tsoLH = |tpLHm - tpLHn|, tsoHL = |tpHLm - tpHLn|
3/8
74VHC244
CAPACITIVE CHARACTERISTICS
Symbol
Parameter
Test Conditions
Value
T A = 25 o C
Min.
CIN
Input Capacitance
Typ.
4
Unit
-40 to 85 o C
Max.
10
Min.
Max.
10
pF
COUT
Output Capacitance
6
pF
CPD
Power Dissipation
Capacitance (note 1)
19
pF
1) CPD 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. ICC(opr) = CPD • VCC • fIN + ICC/48(per Gate)
DYNAMIC SWITCHING CHARACTERISTICS
Symbol
Parameter
Test Conditions
Value
V CC
(V)
T A = 25 o C
Min. Typ. Max.
Dynamic Low Voltage
Quiet Output (note 1, 2)
5.0
0.6
VIHD
Dynamic High Voltage
Input (note 1, 3)
5.0
VILD
Dynamic Low Voltage
Input (note 1, 3)
5.0
VOLP
VOLV
-0.9
CL = 50 pF
Unit
-40 to 85 o C
Min.
Max.
0.9
-0.6
3.5
V
1.5
1) Worst case package.
2) Max number of outputs defined as (n). Data inputs are driven 0V to 5.0V, (n -1) outputs switching and one output at GND.
3) Max number of data inputs (n) switching. (n-1) switching 0V to 5.0V. Inputs under test switching: 5.0V to threshold (VILD), 0V to threshold (VIHD), f=1MHz.
TEST CIRCUIT
TEST
tPLH, tPHL
SWITCH
Open
tPZL, tPLZ
VCC
tPZH, tPHZ
GND
CL = 15/50 pF or equivalent (includes jig and probe capacitance)
RL = R1 = 1KΩ or equivalent
RT = ZOUT of pulse generator (typically 50Ω)
4/8
74VHC244
WAVEFORM 1: PROPAGATION DELAYS (f=1MHz; 50% duty cycle)
WAVEFORM 2: OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle)
5/8
74VHC244
SO-20 MECHANICAL DATA
mm
DIM.
MIN.
TYP.
A
a1
inch
MAX.
MIN.
TYP.
2.65
0.10
0.104
0.20
a2
MAX.
0.004
0.007
2.45
0.096
b
0.35
0.49
0.013
0.019
b1
0.23
0.32
0.009
0.012
C
0.50
0.020
c1
45 (typ.)
D
12.60
13.00
0.496
0.512
E
10.00
10.65
0.393
0.419
e
1.27
0.050
e3
11.43
0.450
F
7.40
7.60
0.291
0.299
L
0.50
1.27
0.19
0.050
M
S
0.75
0.029
8 (max.)
P013L
6/8
74VHC244
TSSOP20 MECHANICAL DATA
mm
DIM.
MIN.
inch
TYP.
MAX.
A
MIN.
TYP.
MAX.
1.1
0.433
A1
0.05
0.10
0.15
0.002
0.004
0.006
A2
0.85
0.9
0.95
0.335
0.354
0.374
b
0.19
0.30
0.0075
0.0118
c
0.09
0.2
0.0035
0.0079
D
6.4
6.5
6.6
0.252
0.256
0.260
E
6.25
6.4
6.5
0.246
0.252
0.256
E1
4.3
4.4
4.48
0.169
0.173
0.176
e
0.65 BSC
0.0256 BSC
K
0o
4o
8o
0o
4o
8o
L
0.50
0.60
0.70
0.020
0.024
0.028
A
A2
A1
b
K
e
L
E
c
D
E1
PIN 1 IDENTIFICATION
1
7/8
74VHC244
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is
granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are
subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products
are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
The ST logo is a trademark of STMicroelectronics
© 1999 STMicroelectronics – Printed in Italy – All Rights Reserved
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8/8
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