DS7820A/DS8820A
Dual Line Receiver
General Description
The DS7820A and the DS8820A are improved performance
digital line receivers with two completely independent units
fabricated on a single silicon chip. Intended for use with digi-
tal systems connected by twisted pair lines, they have a dif-
ferential input designed to reject large common mode sig-
nals while responding to small differential signals. The output
is directly compatible with TTL or LS integrated circuits.
The response time can be controlled with an external capaci-
tor to reject input noise spikes. The output state is a logic "1"
for both inputs open. Termination resistors for the twisted
pair line are also included in the circuit. Both the DS7820A
and the DS8820A are specified, worst case, over their full
operating temperature range (-55C to +125C and 0C to
70C respectively), over the entire input voltage range, for
10% supply voltage variations.
Features
n
Operation from a single +5V logic supply
n
Input voltage range of
15V
n
Strobe low forces output to "1" state
n
High input resistance
n
Fanout of ten with TTL integrated circuits
n
Outputs can be wire OR'ed
n
Series 54/74 compatible
Connection Diagram
Dual-in-Line Package
DS005797-2
Note 1: Pin 7 connected to bottom of cavity package.
Top View
Order Number DS7820AJ or DS8820AN See NS Package Number J14A or N14A
For Complete Military 883 Specificatons, See RETS Data Sheet.
Order Number DS7820AJ/883
See NS Package Number J14A or W14B
May 1999
DS7820A/DS8820A
Dual
Line
Receiver
1999 National Semiconductor Corporation
DS005797
www.national.com
Absolute Maximum Ratings
(Note 3)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage
8.0V
Common-Mode Voltage
20V
Differential Input Voltage
20V
Strobe Voltage
8.0V
Output Sink Current
50 mA
Storage Temperature Range
-65C to 150C
Maximum Power Dissipation (Note 2) at 25C
Cavity Package
Molded Package
1308 mW
1207 mW
Lead Temperature (Soldering, 4 sec.)
260C
Operating Conditions
Min
Max
Units
Supply Voltage (V
CC
)
DS7820A
4.5
5.5
V
DS8820A
4.75
5.25
V
Temperature (T
A
)
DS7820A
-55
+125
C
DS8820A
0
+70
C
Note 2: Derate cavity package 8.7 mW/C above 25C; derate molded pack-
age 9.7 mW/C above 25C.
Electrical Characteristics
(Notes 4, 5, 6)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
V
TH
Differential Threshold Voltage
I
OUT
= -400 A,
-3V
V
CM
+3V
0.06
0.5
V
V
OUT
2.5V
-15V
V
CM
+15V
0.06
1.0
V
I
OUT
= +16 mA,
-3V
V
CM
+3V
-0.08
-0.5
V
V
OUT
0.4V
-15V
V
CM
+15V
-0.08
-1.0
V
R
I-
Inverting Input Resistance
-15V
V
CM
+15V
3.6
5
k
R
I+
Non-Inverting Input Resistance
-15V
V
CM
+15V
1.8
2.5
k
R
T
Line Termination Resistance
T
A
= 25C
120
170
250
I
I-
Inverting Input Current
V
CM
= 15V
3.0
4.2
mA
V
CM
= 0V
0
-0.5
mA
V
CM
= -15V
-3.0
-4.2
mA
I
I+
Non-Inverting Input Current
V
CM
= 15V
5.0
7.0
mA
V
CM
= 0V
-1.0
-1.6
mA
V
CM
= -15V
-7.0
-9.8
mA
I
CC
Power Supply Current
One Side Only
I
OUT
= Logical "0"
V
DIFF
= -1V
V
CM
= 15V
3.9
6.0
mA
V
CM
= -15V
9.2
14.0
mA
V
DIFF
= -0.5V, V
CM
= 0V
6.5
10.2
mA
V
OH
Logical "1" Output Voltage
I
OUT
= -400 A, V
DIFF
= 1V
2.5
4.0
5.5
V
V
OL
Logical "0" Output Voltage
I
OUT
= +16 mA, V
DIFF
= -1V
0
0.22
0.4
V
V
SH
Logical "1" Strobe Input Voltage
I
OUT
= +16 mA, V
OUT
0.4V, V
DIFF
= -3V
2.1
V
V
SL
Logical "0" Strobe Input Voltage
I
OUT
= -400 A, V
OUT
2.5V, V
DIFF
= -3V
0.9
V
I
SH
Logical "1" Strobe Input Current
V
STROBE
= 5.5V, V
DIFF
= 3V
0.01
5.0
A
I
SL
Logical "0" Strobe Input Current
V
STROBE
= 0.4V, V
DIFF
= -3V
-1.0
-1.4
mA
I
SC
Output Short Circuit Current
V
O
= 0V, V
CC
= 5.5V, V
STROBE
= 0V
-2.8
-4.5
-6.7
mA
Note 3: "Absolute Maximum Ratings" are those values beyond which the safety of the device cannot be guaranteed. Except for "Operating Temperature Range" they
are not meant to imply that the devices should be operated at these limits. The table of "Electrical Characteristics" provides conditions for actual device operation.
Note 4: These specifications apply for 4.5V
V
CC
5.5V, -15V
V
CM
15V and -55C
T
A
+125C for the DS7820A or 4.75V
V
CC
5.25V, 0C
T
A
+70C
for the DS8820A unless otherwise specified. Typical values given are for V
CC
= 5.0V, T
A
= 25C and V
CM
= 0V unless stated differently.
Note 5: All currents into device pins shown as positive, out of device pins as negative, all voltages referenced to ground unless otherwise noted. All values shown
as max or min on absolute value basis.
Note 6: Only one output at a time should be shorted.
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2
Switching Characteristics
T
A
= 25C, V
CC
= 5V, unless otherwise noted
Symbol
Parameter
Conditions
Min
Typ
Max
Units
t
pd0
Propagation Delay, Differential
Input to "0" Output
R
L
= 400
, C
L
= 15 pF, see Figure 1
30
45
ns
t
pd1
Propagation Delay, Differential
Input to "1" Output
27
40
ns
t
pd0
Propagation Delay, Strobe
Input to "0" Output
16
25
ns
t
pd1
Propagation Delay, Strobe
Input to "1" Output
18
30
ns
AC Test Circuit and Waveforms
DS005797-7
Note 7: *Includes Jig and Probe Capacitance
DS005797-8
A = Differential Input to "0" Output
B = Differential Input to "1" Output
C = Strobe Input to "0" Output
D = Strobe Input to "1" Output
FIGURE 1.
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3
Typical Performance Characteristics
Supply Voltage Sensitivity
DS005797-6
Common-Mode Voltage
Sensitivity
DS005797-9
Temperature Sensitivity
DS005797-10
Transfer Function
DS005797-11
Termination Resistance
DS005797-12
Input Characteristics
DS005797-13
Power Supply Current
DS005797-14
Internal Power Dissipation
DS005797-15
Output Voltage Levels
DS005797-16
Differential Input Delays
DS005797-17
Strobe Delays
DS005797-18
Noise Rejection
DS005797-19
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4
Schematic Diagram
Typical Applications
DS005797-1
Note 8: Schematic shows one-half of unit.
Differential Line Driver and Receiver
DS005797-3
Note 9: Optional to control response time.
Single Ended (EIA-RS232C) Receiver with Hysteresis
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5
Typical Applications
(Continued)
DS005797-4
DS005797-5
(Output = "1" for Open Input)
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6
Physical Dimensions
inches (millimeters) unless otherwise noted
Ceramic Dual-In-Line Package (J)
Order Number DS7820AJ or DS7820AJ/883
NS Package Number J14A
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7
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
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accordance with instructions for use provided in the
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significant injury to the user.
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can be reasonably expected to cause the failure of
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www.national.com
Molded Dual-In-Line Package (N)
Order Number DS8820AN
NS Package Number N14A
DS7820A/DS8820A
Dual
Line
Receiver
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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