74VHCT244AM [STMICROELECTRONICS]
OCTAL BUS BUFFER WITH 3 STATE OUTPUTS NON INVERTED; 具有三态输出非反相八路总线缓冲器
| 型号： | 74VHCT244AM |
| 厂家： | 
ST |
| 描述： | OCTAL BUS BUFFER WITH 3 STATE OUTPUTS NON INVERTED |
| 文件： | 总8页 (文件大小：66K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
74VHCT244A
OCTAL BUS BUFFER
WITH 3 STATE OUTPUTS (NON INVERTED)
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HIGH SPEED:tPD =3.9ns (TYP.) atVCC = 5V
LOW POWER DISSIPATION:
ICC =4 µA (MAX.) at TA =25 oC
COMPATIBLEWITH TTL OUTPUTS:
VIH =2V (MIN), VIL = 0.8V(MAX)
POWERDOWN PROTECTIONON INPUTS&
OUTPUTS
SYMMETRICAL OUTPUT IMPEDANCE:
|IOH| = IOL = 8 mA (MIN)
BALANCEDPROPAGATIONDELAYS:
tPLH tPHL
■
■
■
■
■
■
M
T
(Micro Package)
(TSSOPPackage)
ORDER CODES :
74VHCT244AM
74VHCT244AT
OPERATING VOLTAGERANGE:
VCC (OPR)= 4.5V to 5.5V
PIN AND FUNCTION COMPATIBLEWITH
74 SERIES244
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.
■
■
IMPROVED LATCH-UP IMMUNITY
LOWNOISEVOLP = 0.9V(Max.)
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
DESCRIPTION
The 74VHCT244A is an advanced high speed
CMOS OCTAL BUS BUFFER (3-STATE)
fabricated with sub-micron silicon gate and
double-layermetal wiring C2MOS technology.
G output enable governs four BUS BUFFERs.
PIN CONNECTION AND IEC LOGIC SYMBOLS
1/8
August 1999
74VCHT244A
INPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
PIN No
1
SYMBOL NAME AND FUNCTION
1G Output Enable Input
2,4,6,8
9,7,5,3
1A1to1A4 Data Inputs
2Y1to2Y4 Data Outputs
11,13, 15,17 2A1to2A4 Data Inputs
18,16, 14,12 1Y1to1Y4 Data Outputs
19
10
20
2G
GND
VCC
Output Enable Input
Ground (0V)
Positive Supply Voltage
TRUTH TABLE
INPUT
OUTPUT
G
L
An
L
Yn
L
L
H
H
H
X:”H” or”L”
X
Z
Z:Highimpedance
ABSOLUTE MAXIMUM RATINGS
Symbol
VCC
VI
Parameter
Value
Unit
Supply Voltage
-0.5to+7.0
-0.5to+7.0
-0.5to+7.0
V
V
DC Input Voltage
VO
DC Output Voltage (see note 1)
DC Output Voltage (see note 2)
DC Input Diode Current
DC Output Diode Current
DC Output Current
V
VO
-0.5toVCC +0.5
-20
V
IIK
mA
mA
mA
mA
oC
oC
IOK
20
±
IO
± 25
± 50
ICC orIGND DC VCC or Ground Current
Tstg
TL
Storage Temperature
-65to+150
300
Lead Temperature (10 sec)
AbsoluteMaximum Ratingsarethose values beyond whichdamage tothe device may occur. Functional operation under these condition isnot implied.
1)Outputin OFFState
2)High or Low State
RECOMMENDED OPERATING CONDITIONS
Symbol
VCC
VI
Parameter
Value
4.5to5.5
0to5.5
Unit
V
Supply Voltage
Input Voltage
V
VO
Output Voltage (see note 1)
0to5.5
V
VO
Output Voltage (see note 2)
0toVCC
-40to+85
0to20
V
oC
Top
Operating Temperature
dt/dv
ns/V
Input Rise and Fall Time (see note 3) (VCC = 5.0 ± 0.5V)
1)Outputin OFFState
2)High or Low State
3)VIN from0.8Vto2 V
2/8
74VHCT244A
DC SPECIFICATIONS
Symbol
Parameter
Test Conditions
VCC
(V)
Value
TA = 25 oC
Min. Typ. Max. Min. Max.
Unit
-40 to 85 oC
VIH
VIL
High Level Input
Voltage
4.5to5.5
2
2
V
V
Low Level Input
Voltage
4.5to5.5
0.8
0.8
VOH
High Level Output
Voltage
4.5
4.5
I =-50 A
4.4
4.5
0.0
4.4
3.8
µ
O
V
IO=-8mA
3.94
VOL
Low Level Output
Voltage
4.5
I =50 A
0.1
0.36
±0.25
0.1
0.44
±2.5
µ
O
V
4.5
IO=8mA
IOZ
High Impedance
Output Leakage
Current
4.5to5.5
V = VIH orVIL
µA
I
VO =0V to5.5V
II
Input Leakage Current
0to5.5
5.5
VI =5.5Vor GND
±0.1
±1.0
µA
ICC
Quiescent Supply
Current
V =VCC orGND
I
2
20
A
µ
∆ICC
Additional Worst Case
Supply Current
5.5
0
One Input at 3.4V,
other input at VCC or
GND
1.35
0.5
1.5
5.0
mA
IOPD
Output Leakage
Current
VOUT =5.5V
A
µ
AC ELECTRICAL CHARACTERISTICS (Input tr = tf =3 ns)
Symbol
Parameter
Test Condition
Value
TA = 25 oC
Unit
VCC
CL
-40 to 85 oC
(V)
(pF)
Min. Typ. Max. Min. Max.
(*)
tPLH
tPHL
Propagation Delay
Time
5.0
15
50
5.4
5.9
7.7
8.2
8.8
7.4
8.4
1.0
1.0
1.0
1.0
1.0
8.5
9.5
ns
ns
ns
(*)
5.0
(*)
tPLZ
tPHZ
Output Disable Time
5.0
15
50
50
R =1K
10.4
11.4
11.4
12.0
13.0
13.0
Ω
L
(*)
5.0
(*)
tPZL
tPZH
Output Enable Time
5.0
R =1K
Ω
L
(*) Voltagerangeis5.0V ± 0.5V
3/8
74VCHT244A
CAPACITIVE CHARACTERISTICS
Symbol
Parameter
Test Conditions
Value
TA = 25 oC
Min. Typ. Max. Min. Max.
Unit
-40 to 85 oC
CIN
Input Capacitance
4
9
10
10
pF
pF
pF
COUT Output Capacitance
CPD
Power Dissipation
18
Capacitance (note 1)
1)CPD isdefined as thevalue ofthe IC’sinternal equivalent capacitance whichiscalculated fromthe operating current consumption without load. (Referto
TestCircuit).Average operating current can beobtained bythe followingequation. ICC(opr)= CPD • VCC • fIN + ICC/48(per Gate)
DYNAMIC SWITCHING CHARACTERISTICS
Symbol
Parameter
Test Conditions
VCC
(V)
Value
TA = 25 oC
Min. Typ. Max. Min. Max.
Unit
-40 to 85 oC
VOLP
VOLV
Dynamic Low Voltage
Quiet Output (note 1, 2)
5.0
0.9
1.1
-1.1
2.0
-0.9
V
IHD
Dynamic High Voltage
Input (note 1, 3)
5.0
5.0
CL = 50pF
V
VILD
Dynamic Low Voltage
Input (note 1, 3)
0.8
1)Worstcase package.
2)Max number ofoutputs defined as (n). Datainputs aredriven 0Vto5.0V, (n -1)outputs switching andone outputatGND.
3)Max number ofdatainputs (n)switching.(n-1)switching 0Vto5.0V. Inputsunder testswitching: 5.0Vtothreshold (VILD),0V tothreshold (VIHD),f=1MHz.
TEST CIRCUIT
TEST
SWITCH
Open
tPLH, tPHL
tPZL, tPLZ
tPZH, tPHZ
VCC
GND
CL = 15/50 pF or equivalent (includes jig and probe capacitance)
RL =R1 =1KΩ orequivalent
RT = ZOUT ofpulse generator (typically50Ω)
4/8
74VHCT244A
WAVEFORM 1: PROPAGATION DELAYS
(f=1MHz; 50% duty cycle)
WAVEFORM 2: OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle)
5/8
74VCHT244A
SO-20 MECHANICAL DATA
mm
inch
TYP.
DIM.
MIN.
TYP.
MAX.
2.65
0.20
2.45
0.49
0.32
MIN.
MAX.
0.104
0.007
0.096
0.019
0.012
A
a1
a2
b
0.10
0.004
0.35
0.23
0.013
0.009
b1
C
0.50
0.020
c1
D
45 (typ.)
12.60
10.00
13.00
10.65
0.496
0.393
0.512
0.419
E
e
1.27
0.050
0.450
e3
F
11.43
7.40
0.50
7.60
1.27
0.75
0.291
0.19
0.299
0.050
0.029
L
M
S
8 (max.)
P013L
6/8
74VHCT244A
TSSOP20 MECHANICAL DATA
mm
inch
TYP.
DIM.
MIN.
TYP.
MAX.
1.1
MIN.
MAX.
0.433
0.006
0.374
0.0118
0.0079
0.260
0.256
0.176
A
A1
A2
b
0.05
0.85
0.19
0.09
6.4
0.10
0.9
0.15
0.95
0.30
0.2
0.002
0.335
0.0075
0.0035
0.252
0.246
0.169
0.004
0.354
c
D
6.5
6.4
6.6
0.256
0.252
E
6.25
4.3
6.5
E1
e
4.4
4.48
0.173
0.65 BSC
4o
0.0256 BSC
4o
K
0o
8o
0o
8o
L
0.50
0.60
0.70
0.020
0.024
0.028
A2
A
K
L
b
e
A1
E
c
D
E1
PIN 1 IDENTIFICATION
1
7/8
74VCHT244A
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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
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8/8
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