+5 volt power for bus A
MIL-STD-1533 bus driver A, positive signal
MIL-STD-1553 bus driver A, negative signal
Receiver A enable. If low, forces RXA and RXA low (HI-1567) or High (HI-1568)
Ground for bus A
+5 volt power for bus B
MIL-STD-1533 bus driver B, positive signal
MIL-STD-1553 bus driver B, negative signal
Receiver B enable. If low, forces RXB and RXB low (HI-1567) or High (HI-1568)
Ground for bus B
Receiver B output, inverted
Receiver B output, non-inverted
Transmit inhibit, bus B. If high BUSB, BUSB disabled
Transmitter B digital data input, non-inverted
Transmitter B digital data input, inverted
Receiver A output, inverted
Receiver A output, non-inverted
Transmit inhibit, bus A. If high BUSA, BUSA disabled
Transmitter A digital data input, non-inverted
Transmitter A digital data input, inverted
The HI-1567 family of data bus transceivers contains differ-
ential voltage source drivers and differential receivers. It is in-
tended for applications using a MIL-STD-1553 A/B data bus.
The device produces a trapezoidal output waveform during
Data input to the device’s transmitter section is from the com-
plementary CMOS /TTL inputs TXA/B and TXA/B. The
transmitter accepts Manchester II bi-phase data and con-
verts it to differential voltages on BUSA/B and BUSA/B. The
transceiver outputs are either direct- or transformer-coupled
to the MIL-STD-1553 data bus. Both coupling methods pro-
duce a nominal voltage on the bus of 7.5 volts peak to peak.
comparator that produces CMOS/TTL data at the RXA/B
and RXA/B output pins. When the MIL-STD-1553 bus is idle
and RXENA or RXENB are high, RXA/B will be logic “0” on
HI-1567 and logic “1” on HI-1568.
The receiver outputs are forced to the bus idle state (logic “0”
for HI-1567 or logic “1” for HI-1568) when RXENA or RXENB
MIL-STD-1553 BUS INTERFACE
A direct-coupled interface (see Figure 2) uses a 1:2.5 ratio
isolation transformer and two 55 ohm isolation resistors
between the transformer and the bus. The primary center-
tap of the isolation transformer must be connected to GND.
The transmitter is automatically inhibited and placed in the
high impedance state when both TXA/B and TXA/B are
driven with the same logic state. A logic “1” applied to the
TXINHA/B input forces the transmitter to the high impedance
state, regardless of the state of TXA/B and TXA/B.
The receiver accepts bi-phase differential data from the MIL-
STD-1553 bus through the same direct- or transformer-
coupled interface as the transmitter. The receiver’s differen-
tial input stage drives a filter and threshold
In a transformer-coupled interface (see Figure 2), the
transceiver is connected to a 1:1.79 isolation transformer
which in turn is connected to a 1:1.4 coupling transformer.
The transformer coupled method also requires two coupling
resistors equal to 75% of the bus characteristic impedence
(Zo) between the coupling transformer and the bus.
Figure 3 and Figure 4 show test circuits for measuring
electrical characteristics of both direct- and transformer-
coupled interfaces respectively. (See electrical
characteristics on the following pages).
HOLT INTEGRATED CIRCUITS