ACT ACT4468DI, ACT4468DFI, ACT4468DF, ACT4468D Datasheet

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– Data Bus Modules For The Future © SCD4468D REV B 5/25/00

Features

ACT4468D Dual Transceiver

ACT4468D

Dual Transceivers for MIL-STD-1553

• World’s smallest and lowest standby power dual
transceiver 0.3" x 1" packages

• Dual transceiver meets military data bus
requirements, MIL-STD-1553 and MIL-STD-1760

• Low power dissipation at full output power

• Single +5V power supply

• Current source output

• Monolithic construction using dielectrically
isolated(D.I.)

• Processed and screened to MIL-STD-883 specs

• DESC SMD# 5962–92061 Pending

TX DATA IN
TX DATA IN

TX INHIBIT

+5 V

GROUND

STROBE

DRIVER

INPUT
AMP

SHAPING

REFERENCE

ACTIVE
FILTER

OUTPUT
STAGE

COMP.

COMP.

Block Diagram (without Transformer), 1/2 of unit shown

TX/RX

TX/RX

RX DATA OUT

RX DATA OUT

CIRCUIT TECHNOLOGY

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General Description

The Aeroflex Circuit Technology
Model ACT4468D is a next
generation D.I. monolithic transceiver
which provide full compliance with
MIL-STD-1553/1760 and data bus
requirements in the smallest
packages with the lowest standby
power consumption and one power
supply operation.

The dual channel Model ACT4468D
perform the front-end analog function
of inputting and outputting data
through a transformer to a
MIL-STD-1553/1760 data bus.

Design of these transceivers reflects
particular attention to active filter
performance. This results in low bit
and word error rate with superior
waveform purity and minimal zero
crossover distortion. Efficient
transmitter electrical and thermal
design provides low internal power
dissipation and heat rise at high as
well as low duty cycles.

Each channel of the dual transceiver
is completely separate from the other
and fully independent. This includes
power leads as well as signal lines.
Hence, each channel may be
connected to a different data bus with
no interaction.

Transmitter:

The Transmitter section accepts
bi-phase TTL data at the input and
when coupled to the data bus with a
1:2.5 transformer, isolated on the
data bus side with two 52.5 Ohm fault
isolation resistors, and loaded by two
70 Ohm terminations plus additional
receivers, the data bus signal
produced is 7.5Volts nominal P-P at
A-A’. (See Figure 5.) When both
DATA and DATA
high, the transmitter output becomes

inputs are held low or

echnology

Aeroflex Circuit Technology

SCD4468D REV B 5/25/00 Plainview NY [phone]

CIRCUIT TECHNOLOGY

a high impedance and is “removed”
from the line. In addition, an
overriding “INHIBIT" input provides
for the removal of the transmitter
output from the line. A logic “1”
applied to the “INHIBIT” takes
priority over the condition of the data
inputs and disables the transmitter.
(See Transmitter Logic Waveform,
Figure 1.)

The transceiver utilizes an active
filter to suppress harmonics above
1MHz. The Transmitter may be
safely operated at 100% duty cycle
for an indefinite period into a short
circuited 1553 bus.

Figure 1. Transmitter Logic Waveforms

DATA IN

Receiver:

The Receiver section accepts
bi-phase differential data at the input
and produces two TTL signals at the
output. The outputs are DATA and

, and represent positive and

DATA
negative excursions of the input
beyond a pre-determined
threshold.(See Receiver Logic
Waveform. Figure 2.)

The pre-set internal thresholds will
detect data bus signals exceeding

1.150 Volts P-P and reject signals
less than 0.6 volts P-P when used
with a 1:2.5 turns ratio transformer.
(See Figure 5 for transformer data
and typical connection.)

DATA IN

INHIBIT

LINE TO LINE

OUTPUT

NOTES:

1.DATA and DATA

2.DATA and DATA

inputs must be complementary waveforms or 50% duty cycle average, with no delays between them.
must be in the same state during off time (both high or low).

Figure 2. Receiver Logic Waveforms

LINE TO LINE
INPUT

DATA OUT

DATA

OUT

NOTE: Waveforms shown are for normally low devices. For normally high receiver output

Note overlap

level devices, the receiver outputs are swapped as shown by the dashed lines.

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