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RM3283
PRODUCT SPECIFICATION
6
Truth Table
ARINC nputs
V(A) - V(B)
Null
Low
High
X
X
X
Test Inputs
Outputs
Output
State
Null
Low
High
Low
High
Null
TESTA
0
0
0
0
1
1
TESTB
0
0
0
1
0
1
OUTA
0
0
1
0
1
0
OUTB
0
1
0
1
0
0
Applications Discussion
The standard connections for the RM3283 are shown in
Figure 10. Dual supplies from
±
12 to
±
15 VDC are recom-
mended for the
±
V
S
supplies. Decoupling of all supplies
should be done near the IC to avoid propagation of noise
spikes due to switching transients. The ground connection
should be sturdy and isolated from large switching currents
to provide as quiet a ground reference as possible.
The noise filter capacitors are optional and are added to
provide extra noise immunity by limiting bandwidth of the
input signal before it reaches the window comparator stage.
Two capacitors are required for each channel and they must
all be the same value. The suggested capacitor value for a
100 kHz operation is 39 pF. For lower data rates, larger val-
ues of capacitance may be used to yield better node perfor-
mance. To get optimum performance, the following equation
can be used to calculate capacitor value for a specific data
rate:
Where C
FILTER
is the capacitor value in pF, and F
O
is the
input frequency (10 kHz
£
F
O
£
150 kHz).
The RM3283 can be used with the Fairchild RM3182/
RM3182A line driver to provide a complete analog ARINC
429 interface. A simple application which can be used for
systems requiring a repeater-type circuit for long transmis-
sions is given in Figure 11. More RM3182 drivers may be
added to test multiple ARINC channels, as shown.
C
FILTER
3.95
10
6
–
′
F
O
=