
31
INTERFACE TO MIL-STD-1553 BUS
FIGURE 14 illustrates the interface between the BU-61703/5
SSRT and a MIL-STD-1553 bus. Connections for both direct
(short stub) coupling and transformer (long stub) coupling, as
well as the peak-to-peak voltage levels at various points (when
transmitting), are indicated in the diagram.
BU-61703/5
SSRT
DATA
BUS
Z
0
55
55
(1:2.5)
11.6 Vpp
28 Vpp
1 FT MAX
Z
0
(1:1.79)
11.6 Vpp
20 Vpp
(1:1.41)
COUPLING
TRANSFORMER
0.75 Z
0
0.75 Z
0
LONG STUB
(TRANSFORMER
COUPLED)
20 FT MAX
28 Vpp
SHORT STUB
(DIRECT COUPLED)
OR
NOTE: Z
0 =
70 TO 85 OHMS
ISOLATION
TRANSFORMER
ISOLATION
TRANSFORMER
NOTES:
1. Shown for one of two redundant buses that interface to the BU-61703/5 hybrid.
2. Transmitted voltage level on 1553 bus is 6 Vp-p min, 7 Vp-p nominal, 9 Vp-p max.
3. Transmitted voltage for a transformer-coupled stub is 18 Vp-p min, 27 Vp-p max for
MIL-STD-1553B; 20 Vp-p min, 27 Vp-p max for MIL-STD-1760.
4. Required tolerance on isolation resistors is 2%. Instantaneous power dissipation
(when transmitting) is approximately 0.45 W typ, 0.8 W (max) for each isolation resistor.
FIGURE 14. SSRT INTERFACE TO MIL-STD-1553 BUS.