54ABT245.pdf
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261 KB
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Pobierz
July 1998
54ABT245
Octal Bidirectional Transceiver with TRI-STATE
®
Outputs
General Description
The ’ABT245 contains eight non-inverting bidirectional buff-
ers with TRI-STATE outputs and is intended for bus-oriented
applications. Current sinking capability i
s 4
8 mA on both the
A and B ports. The Transmit/Receive (T/R) input determines
the direction of data flow through the bidirectional trans-
ceiver. Transmit (active HIGH) enables data from A ports to B
ports; Receive (active LOW) enables data from B ports to A
ports. The Output Enable input, when HIGH, disables both A
and B ports by placing them in a High Z condition.
n
Guaranteed output skew
n
Guaranteed multiple output switching specifications
n
Output switching specified for both 50 pF and 250 pF
loads
n
Guaranteed simultaneous switching, noise level and
dynamic threshold performance
n
Guaranteed latchup protection
n
High impedance glitch-free bus loading during entire
power up and power down cycle
n
Non-destructive hot insertion capability
n
Disable time is less than enable time to avoid bus
contention
n
Standard Microcircuit Drawing (SMD) 5962-9214801
Features
n
Bidirectional non-inverting buffers
n
A and B output sink capability of 48 mA, source
capability of 24 mA
Ordering Code:
Military
Package
Package Description
Number
54ABT245J-QML
J20A
20-Lead Ceramic Dual-In-Line
54ABT245W-QML
W20A
20-Lead Cerpak
54ABT245E-QML
E20A
20-Lead Ceramic Leadless Chip Carrier, Type C
Logic Symbol
DS100204-1
TRI-STATE
®
is a registered trademark of National Semiconductor Corporation.
www.national.com
© 1998 National Semiconductor Corporation
DS100204
Connection Diagrams
Pin Assignment for DIP
and Flatpak.
Pin Assignment for LCC
DS100204-3
Pin Descriptions
Pi
n Names
DS100204-5
Description
O
E
Output Enable Input (Active LOW)
T/R
Transmit/Receive Input
A
0
–A
7
Side A Inputs or TRI-STATE Outputs
B
0
–B
7
Side B Inputs or TRI-STATE Outputs
Truth Table
Inputs
Output
OE
T/R
L
L
Bus B Data to Bus A
L
H
Bus A Data to Bus B
H
X
High Z State
H
=
HIGH Voltage Level
L
=
LOW Voltage Level
X = Immaterial
Logic Diagram
DS100204-4
www.national.com
2
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Storage Temperature
in LOW State (Max)
twice the rated I
OL
(mA)
DC Latchup Source Current
−500 mA
Over Voltage Latchup (I/O)
10V
Recommended Operating
Conditions
Free Air Ambient Temperature
Military
−65˚C to +150˚C
Ambient Temperature under Bias
−55˚C to +125˚C
Junction Temperature under Bias
Ceramic
−55˚C to +175˚C
−55˚C to +125˚C
V
CC
Pin Potential to
Ground Pin
Supply Voltage
Military
−0.5V to +7.0V
+4.5V to +5.5V
Input Voltage (Note 2)
−0.5V to +7.0V
Minimum Input Edge Rate
t)
Data Input 50 mV/ns
Enable Input 20 mV/ns
Note 1:
Absolute maximum ratings are values beyond which the device may
be damaged or have its useful life impaired. Functional operation under these
conditions is not implied.
Note 2:
Either voltage limit or current limit is sufficient to protect inputs.
(
D
V/
D
Input Current (Note 2)
−30 mA to +5.0 mA
Voltage Applied to Any Output
in the Disabled or
Power-off State
−0.5V to 5.5V
in the HIGH State
−0.5V to V
CC
Current Applied to Output
DC Electrical Characteristics
Symbol
Parameter
ABT245
Conditions
Units
V
CC
Min
Typ
Max
V
IH
Input HIGH Voltage
2.0
V
Recognized HIGH Signal
V
IL
Input LOW Voltage
0.8
V
Recognized LOW Signal
I
IN
=
−18 mA (OE, T/R)
V
CD
Input Clamp Diode Voltage
−1.2
V
Min
I
OH
=
−3 mA (A
n
,B
n
)
V
OH
Output HIGH
Voltage
54ABT
2.5
V
Min
54ABT
2.0
V
Min
I
OH
= −24 mA (A
n
,B
n
)
V
OL
Output LOW
Voltage
54ABT
0.55
I
OL
= 48 mA (A
n
,B
n
)
V
Min
V
IN
=
2.7V (OE, T/R) (Note 3)
I
IH
Input HIGH Current
5
µA
Max
V
IN
=
V
CC
(OE, T/R)
5
V
IN
=
7.0V (OE, T/R)
I
BVI
Input HIGH Current Breakdown Test
7
µA
Max
V
IN
=
5.5V (A
n
,B
n
)
I
BVIT
Input HIGH Current Breakdown Test
(I/O)
100
µA
Max
V
IN
=
0.5V (OE, T/R) (Note 3)
I
IL
Input LOW Current
−5
µA
Max
V
IN
=
0.0V (OE, T/R)
−5
I
ID
=
1.9 µA (OE, T/R)
All Other Pins Ground
ed
V
ID
Input Leakage Test
4.75
V
0.0
V
OUT
=
2.7V (A
n
,B
n
);
OE
=
2.0V
I
IH
+I
OZH
Output Leakage Current
50
µA
0 − 5.5V
V
OUT
=
0.5V (A
n
,B
n
); OE
=
2.0V
I
IL
+I
OZL
Output Leakage Current
−50
µA
0 − 5.5V
V
OUT
=
0.0V (A
n
,B
n
)
I
OS
Output Short-Circuit Current
−100
−275
mA
Max
V
OUT
=
V
CC
(A
n
,B
n
)
I
CEX
Output High Leakage Current
50
µA
Max
V
OUT
=
5.5V (A
n
,B
n
);
All Others GND
I
ZZ
Bus Drainage Test
100
µA
0.0
I
CCH
Power Supply Current
50
µA
Max
All Outputs HIGH
I
CCL
Power Supply Current
30
mA
Max
All Outputs LOW
OE
=
V
CC
, T/R
=
GND or V
CC
;
All Other GND or V
CC
I
CCZ
Power Supply Current
50
µA
Max
I
CCT
Additional
Outputs Enabled
2.5
mA
V
I
= V
CC
− 2.1V
I
CC
/Input
Outputs TRI-STATE
2.5
mA
Max
OE, T/R V
I
= V
CC
− 2.1V
Outputs TRI-STATE
50
µA
Data Input V
I
= V
CC
− 2.1V
All Others at V
CC
or GND.
3
www.national.com
DC Electrical Characteristics
(Continued)
Symbol
Parameter
ABT245
Conditions
Units
V
CC
Min
Typ
Max
I
CCD
Dynamic I
CC
No Load
0.1
mA/
MHz
Outputs Open
OE
=
GND, T/R
=
GND or V
CC
One Bit Toggling, 50% Duty Cycle
(Note 4)
(Note 3)
Max
Note 3:
Guaranteed but not tested.
Note 4:
For 8 bits toggling, I
CCD
<
0.8 mA/MHz.
DC Electrical Characteristics
Conditions
C
L
=
50 pF,
R
L
=
500
Symbol
Parameter
Min
Max
Units
V
CC
W
T
A
=
25˚C (Note 5)
V
OLP
Quiet Output Maximum Dynamic V
OL
1.1
V
5.0
T
A
=
25˚C(Note 5)
V
OLV
Quiet Output Minimum Dynamic V
OL
-0.45
V
5.0
Note 5:
Max number of outputs defined as (n).n−1data inputs are driven 0V to 3V. One output at LOW.
AC Electrical Characteristics
Symbol
Parameter
54ABT
Units
T
A
=
−55˚C to +125˚C
V
CC
=
4.5V–5.5V
C
L
=
50 pF
Min
Max
t
PLH
Propagation Delay
1.0
4.8
ns
t
PHL
Data to Outputs
1.0
4.8
t
PZH
Output Enable
1.0
6.7
ns
t
PZL
Time
2.0
7.5
t
PHZ
Output Disable
1.7
7.4
ns
t
PLZ
Time
1.7
6.5
Capacitance
Symbol
Parameter
Typ
Units
Conditions
T
A
=
25˚C
V
CC
=
0V (OE , T/R)
C
IN
Input Capacitance
5.0
pF
V
CC
=
5.0V (A
n
,B
n
)
C
I/O
(Note 6)
I/O Capacitance
11.0
pF
Note 6:
C
I/O
is measured at frequency f
=
1 MHz, per MIL-STD-883B, Method 3012.
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4
Capacitance
(Continued)
t
PLH
vs Temperature (T
A
)
C
L
=
50 pF, 1 Output Switching
t
PHL
vs Temperature (T
A
)
C
L
= 50 pF, 1 Output Switching
DS100204-14
DS100204-15
t
PLH
vs Load Capacitance
1 Output Switching, T
A
=
25˚C
t
PHL
vs Load Capacitance
1 Output Switching, T
A
=
25˚C
DS100204-16
DS100204-17
Dashed lines represent design characteristics; for specified guarantees, refer to AC Characteristics Table.
t
PLH
vs Load Capacitance
8 Outputs Switching, T
A
=
−40˚C to +85˚C
t
PHL
vs Load Capacitance
8 Outputs Switching, T
A
=
25˚C
DS100204-18
DS100204-19
5
www.national.com
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