HD74LVC245A
Octal Bidirectional Transceivers with 3-state Outputs
ADE-205-111B(Z)
3rd Edition
December 1996
Description
The HD74LVC245A has eight buffers with three state outputs in a 20 pin package. When (T /
R)
is high,
data flows from the A inputs to the B outputs, and when (T /
R)
is low, data flows from the B inputs to the
A outputs. A and B bus are separated by making enable input (OE) high level. Low voltage and high
speed operation is suitable at the battery drive product (note type personal computer) and low power
consumption extends the life of a battery for long time operation.
Features
•
•
•
•
•
•
V
CC
= 2.0 V to 5.5 V
All inputs V
IH
(Max.) = 5.5 V (@V
CC
= 0 V to 5.5 V)
All input outputs V
I/O
(Max.) = 5.5 V (@V
CC
= 0 V or output off state)
Typical V
OL
ground bounce < 0.8 V (@V
CC
= 3.3 V, Ta = 25°C)
Typical V
OH
undershoot > 2.0 V (@V
CC
= 3.3 V, Ta = 25°C)
High output current ±24 mA (@V
CC
= 3.0 V to 5.5 V)
Function Table
Inputs
OE
L
L
H
H:
L:
X:
Z:
High level
Low level
Immaterial
High impedance
T/
R
L
H
X
Operation
B data to A bus
A data to B bus
Z
HD74LVC245A
Pin Arrangement
T/R 1
A0 2
A1 3
A2 4
A3 5
A4 6
A5 7
A6 8
A7 9
GND 10
20 V
CC
19 OE
18 B0
17 B1
16 B2
15 B3
14 B4
13 B5
12 B6
11 B7
(Top view)
Absolute Maximum Ratings
Item
Supply voltage
Input diode current
Input voltage
Output diode current
Symbol
V
CC
I
IK
V
I
I
OK
Ratings
–0.5 to 6.0
–50
–0.5 to 6.0
–50
50
Input / output voltage
V
I/O
–0.5 to V
CC
+0.5
–0.5 to 6.0
Output current
V
CC
, GND current / pin
Storage temperature
I
O
I
CC
or I
GND
Tstg
±50
100
–65 to 150
Unit
V
mA
V
mA
mA
V
V
mA
mA
°C
V
I
= –0.5 V
T /
R, OE
V
O
= –0.5 V
V
O
= V
CC
+0.5 V
Output "H" or "L"
Output "Z" or V
CC
:OFF
Conditions
Note: The absolute maximum ratings are values which must not individually be exceeded, and furthermore,
no two of which may be realized at the same time.
2
HD74LVC245A
Recommended Operating Conditions
Item
Supply voltage
Symbol
V
CC
Ratings
1.5 to 5.5
2.0 to 5.5
Input / output voltage
V
I
V
I/O
0 to 5.5
0 to V
CC
0 to 5.5
Operating temperature
Output current
Ta
I
OH
–40 to 85
–12
–24
*2
I
OL
Input rise / fall time
*1
12
24
*2
t
r
, t
f
10
Unit
V
V
V
V
V
°C
mA
mA
mA
mA
ns/V
V
CC
= 2.7 V
V
CC
= 3.0 V to 5.5 V
V
CC
= 2.7 V
V
CC
= 3.0 V to 5.5 V
Conditions
Data retention
At operation
T /
R, OE
Output "H" or "L"
Output "Z" or V
CC
:OFF
Notes: 1. This item guarantees maximum limit when one input switches.
Waveform : Refer to test circuit of switching characteristics.
2. duty cycle
≤
50%
3
嵌入式系统
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