DM74ALS245A Octal 3-STATE Bus Transceiver
September 1986
Revised February 2000
DM74ALS245A
Octal 3-STATE Bus Transceiver
General Description
This advanced low power Schottky device contains 8 pairs
of 3-STATE logic elements configured as octal bus trans-
ceivers. These circuits are designed for use in memory,
microprocessor systems and in asynchronous bidirectional
data buses. Two way communication between buses is
controlled by the (DIR) input. Data transmits either from the
A bus to the B bus or from the B bus to the A bus. Both the
driver and receiver outputs can be disabled via the (G)
enable input which causes outputs to enter the high imped-
ance mode so that the buses are effectively isolated.
Features
s
Advanced oxide-isolated, ion-implanted Schottky TTL
process
s
Non-inverting logic output
s
Glitch free bus during power up and down
s
3-STATE outputs independently controlled on A and B
buses
s
Low output impedance to drive terminated transmission
lines to 133Ω
s
Switching response specified into 500Ω/50 pF
s
Specified to interface with CMOS at V
OH
=
V
CC
−
2V
s
PNP inputs to reduce input loading
s
Switching specifications guaranteed over full tempera-
ture and V
CC
range
Ordering Code:
Order Number
DM74ALS245AWM
DM74ALS245ASJ
DM74ALS245AMSA
DM74ALS245AN
Package Number
M20B
M20D
MSA20
N20A
Package Description
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
20-Lead Shrink Small Outline Package (SSOP), EIAJ TYPE II, 5.3mm Wide
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Function Table
Control
Inputs
G
L
L
H
DIR
L
H
X
B Data to A Bus
A Data to B Bus
Hi-Z
Operation
H
=
HIGH Logic Level
L
=
LOW Logic Level
X
=
Either HIGH or LOW Logic Level
© 2000 Fairchild Semiconductor Corporation
DS006213
www.fairchildsemi.com
DM74ALS245A
Absolute Maximum Ratings
(Note 1)
Supply Voltage
Input Voltage
Control Inputs
I/O Ports
Operating Free Air Temperature Range
Storage Temperature Range
Typical
θ
JA
N Package
M Package
53.0°C/W
72.0°C/W
7V
5.5V
0°C to
+70°C
−65°C
to
+150°C
Note 1:
The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
7V
Recommended Operating Conditions
Symbol
V
CC
V
IH
V
IL
I
OH
I
OL
T
A
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Operating Free Air Temperature
0
Parameter
Min
4.5
2
0.8
−15
24
70
Typ
5
Max
5.5
Units
V
V
V
mA
mA
°C
Electrical Characteristics
over recommended operating free air temperature range. All typical values are measured at V
CC
=
5V, T
A
=
25°C.
Symbol
V
IK
V
OH
Parameter
Input Clamp Voltage
HIGH Level
Output Voltage
V
OL
I
I
I
IH
I
IL
I
O
I
CC
LOW Level Output Voltage
Input Current at Maximum
Input Voltage
HIGH Level Input Current
LOW Level Input Current
Output Drive Current
Supply Current
Conditions
V
CC
=
4.5V, I
IN
= −18
mA
V
CC
=
4.5V, I
OH
= −3
mA
V
CC
=
4.5V, I
OH
=
Max
I
OH
= −0.4
mA, V
CC
=
4.5V to 5.5V
V
CC
=
4.5V
V
CC
=
5.5V
I
OL
=
24 mA
V
IN
=
7V
V
IN
=
5.5V
V
CC
=
5.5V, V
IN
=
2.7V
V
CC
=
5.5V, V
IN
=
0.4V
V
CC
=
5.5V, V
OUT
=
2.25V
V
CC
=
5.5V
Outputs HIGH
Outputs LOW
3-STATE
−30
30
36
38
Control Inputs
A or B Ports
2.4
2
V
CC
−
2
0.35
0.5
0.1
0.1
20
−0.1
−112
45
55
58
3.2
2.3
Min
Typ
Max
−1.5
Units
V
V
V
V
V
mA
µA
mA
mA
mA
mA
mA
Switching Characteristics
Symbol
t
PLH
t
PHL
t
PZL
t
PZH
t
PLZ
t
PHZ
Parameter
Propagation Delay Time
LOW-to-HIGH Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
Output Enable Time to LOW Level
Output Enable Time to HIGH Level
Output Disable Time from LOW Level
Output Disable Time from HIGH Level
(Note 2)
Circuit Configuration
Min
3
3
5
5
4
2
Max
10
10
20
20
15
10
Units
ns
ns
ns
ns
ns
ns
over recommended operating free air temperature range
Note 2:
Switching characteristic conditions are V
CC
=
4.5V to 5.5V, R
L
=
500Ω, C
L
=
50 pF.
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