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Octal 3-State Noninverting
Bus Transceiver
These octal bus transceiver are designed for asynchronous two-way
communication between data buses. The control function
implementation minimized external timing requirements.
The device allows data transmission from the A bus to the B bus or
from the B bus to the A bus depending upon the logic level at the
directional control (DIR) input. The enable input(E) can be used to
disable the device so that the buses are effectively isolated.
•
Bidirectional Bus Transceiver in a High-Density 20-Pin Package
•
3-state Outputs Dirve Bus Lines Directly
•
P-N-P Inputs D-C Loading on Bus Li nes
•
Hysteresis at Bus Inputs Improve Noise Margins
•
Typical Propagation Delay Times; Port to Port ... 8 ns
TECHNICAL DATA
IN74LS245
ORDERING INFORMATION
IN74LS245N Plastic
IN74LS245DW SOIC
TA = 0° to 70° C
for all packages
LOGIC DIAGRAM
PIN 20=V
PIN 10 = GND
CC
PIN ASSIGNMENT
FUNCTION TABLE
Control Inputs
Output
Enable
L L Data Transmitted
L H Data Transmitted
H X Buses Isolated
X = don’t care
Direction Operation
from Bus B to
Bus A
from Bus A to
Bus B
(High Impedanc e
State)
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IN74LS245
MAXIMUM RATINGS
*
Symbol Parameter Value Unit
V
CC
V
V
OUT
Supply Voltage 7.0 V
Input Voltage 7.0 V
IN
Output Voltage 5.5 V
Tstg Storage Temperature Range -65 to +150
*
Maximum Ratings are those values beyond which damage to the device may occur.
Functional operation should be restricted to the Recommended Operating Conditions.
RECOMMENDED OPERATING CONDITIONS
Symbol Parameter Min Max Unit
V
CC
V
IH
V
IL
I
OH
I
OL
T
A
Supply Voltage 4.75 5.25 V
High Level Input Voltage 2.0 V
Low Level Input Voltage 0.8 V
High Level Output Current -15 mA
Low Level Output Current 24 mA
Ambient Temperature Range 0 +70
°
C
°
C
DC ELECTRICAL CHARACTERISTICS
over full operating conditions
Guaranteed Limit
Symbol Parameter Test Conditions Min Max U nit
V
V
OH
Input Clamp Voltage VCC = min, IIN = -18 mA -1.5 V
IK
High Level Output Voltage VCC = min, IOH = -1.0 mA 2.7 V
VCC = min, IOH = -3.0 mA 2.4
VCC = min, IOH = -15 mA 2.0
V
OL
Low Level Output Voltage VCC = min, IOL = 12 mA 0.4 V
VCC = min, IOL = 24 mA 0.5
VT+ - VT-Hysteresis VCC = min 0.2 V
I
I
OZH
OZL
I
IH
Output Off Current HIGH VCC = max, V
Output Off Current LOW VCC = max, V
= 2.7 V 20
OUT
= 0.4 V -0.2 mA
OUT
High Level Input Current VCC = max, VIN = 2.7 V 20
VCC = max, VIN = 5.5 V
0.1 mA
(A or B)
VCC = max, VIN = 7.0 V
0.1
for Pin1, Pin 19
I
IL
I
O
Low Level Input Current VCC = max, VIN = 0.4 V -0.2 mA
Output Short Circuit Current VCC = max, VO =0 V
-40 -225 mA
(Note 1)
I
CC
Supply Outputs High VCC = max 70 mA
Current Outputs Low Outputs open 90
All outputs disable 95
µ
A
µ
A
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IN74LS245
Note 1: Not more thanone output should be shorted at a time, and duration of the short-circuit should not exceed
one second.
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IN74LS245
AC ELECTRICAL CHARACTERISTICS
t
= 6.0 ns)
f
(TA = 25°C, VCC = 5.0 V, tr = 15 ns,,
Symbol Parameter Test Condition Min Max Unit
t
PLH
Propagation Delay Time, Low-to-High Level
12 ns
Output (from A or B to Output)
t
t
PHL
PZH
Propagation Delay Time, High-to-Low Level
Output (from A or B to Output)
Output Enable Time to High Level (from OE
CL = 45 pF,
= 667
R
L
12 ns
Ω
40 ns
to Output)
t
PZL
Output Enable Time to Low Level (from OE
40 ns
to Output)
t
t
PHZ
PLZ
Output Disabl e Time from High Level
(from OE to Output) C
Output Disable Time from Low Level
= 5 pF
L
R
= 667
L
25 ns
Ω
25 ns
(from OE to Output)
Figure 1. Switching Waveforms
(See Figure 3)
NOTES A. CL includes probe and jig capacitance.
B. All diodes are 1N916 or 1N3064.
Figure 3. Test Circuit
t
- S1 closed, S2 opened
PZL
t
- S1 opened, S2 closed
PZH
t
, t
PLZ
- S1 and S2 closed
PHZ
Figure 2. Switching Waveforms
(See Figure 4)
NOTES A. CL includes probe and jig capacitance.
B. All diodes are 1N916 or 1N3064.
Figure 4. Test Circuit
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EXPANDED LOGIC DIAGRAM
IN74LS245
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