SCD4435N Rev B

FEATURES

❑

ACT4435N Transceiver meets H009 data bus specifications

❑

Transmitter can be used to drive clock signal line

❑

Operates with ±15 Volts to ±12 Volts power supplies

❑

Direct replacement for CT1641 and CT1816 devices

❑

Voltage source output for higher bus drive power

❑

Plug-in and flat package available

❑

Monolithic construction using linear ASICs

❑

Processed and screened to MIL-STD-883 specs

❑

MIL-PRF-38534 compliant devices available

❑

Aeroflex is a Class H & K MIL-PRF-38534 Manufacturer

GENERAL DESCRIPTION

The Aeroflex Laboratories transceiver model ACT4435N is a new generation monolithic transceiver which provide full compliance with

Macair and MIL-STD-1553 data bus requirements

The model ACT 4435N performs the front-end analog function of inputting and outputting data through a transformer to a H009 data bus.

The 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 ACT 4435N active filter design has additional high frequency roll-off to

provide the required 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, isolated on the

transceiver side with two 35 Ohm bus terminating resistors, with the bus terminated by a 170 Ohm resistor the data bus signal produced is 20.0

Volts typical P-P at A-A’ (See Figure 5). When both DATA and DATA inputs are held low or high, the transmitter output becomes a low

impedance and signal is “removed” from the line. In addition, an overriding “INHIBIT" input returns the output to a high impedance state. 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 H009 specifications. The transmitter may be safely operated

for an indefinite period at 100% duty cycle into a data bus short circuit.

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 Volts P-P and reject signals less than 0.6 Volts P-P when used

with a 1:1 turns ratio transformer (See Figure 5 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.

A low level at the Strobe input inhibits the DATA and DATA outputs. If unused, a 2K Ohm pull-up to +5 Volts is recommended.

ACT4435N Transceiver

Standard Products

for H009 Specification

June 18, 2004

ACT4435NFP / 4435N