SCD4404N Rev C

FEATURES

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ACT4404N transceiver meets MIL-STD-1553A & B, Macair A3818, A4905, A5232 and A5690 specs

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Bipolar supply ±15V to ±12V, logic supply +5V

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Monolithic construction

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Direct replacement for CT3232M

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Voltage source output for higher bus drive power

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Variable receiver threshold capability

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Designed for commercial, industrial and aerospace applications

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MIL-PRF-38534 compliant devices available

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Aeroflex-Plainview is a Class H & K MIL-PRF-38534 manufacturer

GENERAL DESCRIPTION

The Aeroflex-Plainview transceiver model ACT4404N is a new generation monolithic transceiver which provide full compliance

with Macair and MIL-STD-1553 data bus requirements.

The model ACT4404N performs the front-end analog function of inputting and outputting data through a transformer to a

MIL-STD-1553 or Macair data bus. The ACT4404N can be considered a "Universal" Transceiver in that it is compatible with

MIL-STD-1553A/B, Macair (A-3818, A-4905, A-5232 and A-5690).

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. The ACT4404N active filter design has additional high

frequency roll-off to provide the required Macair low harmonic distortion waveform without increasing the pulse delay

characteristics significantly.

Efficient transmitter electrical and thermal design provides low internal power dissipation and heat rise at high and well as low

duty cycles. An optional receiver input threshold adjustment can be accomplished by the use of the ''External Threshold"

terminals.

TRANSMITTER

The Transmitter section accepts bi-phase TTL data at the input and when coupled to the data bus with a 1:1 transformer the data

bus signal produced is 7.0 Volts typical P-P at point A-A’ (See Figure 3 or 4). When both DATA and DATA inputs are held low or

high, the transmitter output becomes 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 Waveforms - Figure 1).

The transmitter utilizes an active filter to suppress harmonics above 1 MHz to meet Macair specifications A-3818, A-4905,

A-5232 and A-5690. The transmitter may be safely operated for an indefinite period at 100% duty cycle into a data bus short

circuit.

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.

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 DATA, and represent positive and negative excursions of the input beyond a pre-determined threshold (See Receiver

Logic Waveforms - Figure 2).

The internal threshold is nominally set to detect data bus signals exceeding 1.05 Vp-p and reject signals less than 0.6 Vp-p when

used with a 1:1 turns ratio transformer (See Figure 3 or 4 for transformer data and typical connection). This threshold setting can

be held by grounding the appropriate pins or modified with the use of external resistors.

recommended.

ACT4404N Single Transceiver

Standard Products

www.aeroflex.com/Avionics

March 4, 2005

for MACAIR (A3818, A4905, A5232, A5690), MIL-STD-1553

& SAE-AS15531