SCD4462D Rev E

FEATURES

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ACT4462D Dual Transceiver meets H009 and MacAir / 1553 / 1760 specifications

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Variable output amplitude adjustment

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H009 or MacAir / MIL-STD-1553 / MIL-STD-1760 – Pin selectable

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H009 transmitter can be used to drive clock signal line

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Bipolar ±15V to ±12V & Logic +5V Supplies

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Voltage source output

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Receiver thresholds adjustable – Using threshold adjustment pins

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1.25"L x 0.61"W, 24 lead, ceramic, hermetic package

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Monolithic construction using linear ASICs

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Processed and screened to MIL-STD-883 specs

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Designed for commercial, industrial and aerospace applications

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

DESCRIPTION

Aeroflex Plainview transceiver model ACT4462D is the first

transceiver to combine H009 Bus and MacAir / 1553 / 1760 Bus

operation in a Variable Amplitude Dual Channel, pin selectable,

hybrid. In addition to pin selectable bus operation the transceiver

allows the user to externally set the receiver threshold, for either

channel, to optimize system performance. Two pins, per channel,

are brought out for external threshold adjustment, and, with the

addition of a resistor from each pin to ground the threshold can be

tailored for each channel separately. This Dual Channel, Variable

Amplitude, Pin Selectable H009 or MacAir/1553/1760

Transceiver allows the user to stock one component when the

system has both a H009 Bus as well as a MacAir/1553/1760 Bus.

It should also appeal to H009/MacAir/1553/1760 test equipment

manufacturers.

TRANSMITTER

H009 OPERATION

is in H009 operation and 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 34 Ohm bus terminating resistors,

with the bus terminated by a 170 Ohm resistor the data bus signal

produced is 21Vp-p typical at A-A' (See Figure 9). 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 “TX INHIBIT" input returns

the output to a high impedance state. A logic “1” applied to the

“TX 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.

MacAIR / 1553 / 1760 OPERATION

When the 1553/H009 select pin is left open circuit, the

transmitter is in the MacAir

/1553 /1760 operation and accepts

bi-phase TTL data at the input and when coupled to the data bus

with a 1:1 transformer, isolated on the data bus side with two 55

Ohm fault isolation resistors, and loaded by two 70 Ohm

terminations plus additional receivers, the data bus signal

produced is 7.0Vp-p minimum at A-A’ (See Figure 11 and 12).

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 “TX INHIBIT" input

provides for the removal of the transmitter output from the line. A

logic “1” applied to the “TX INHIBIT” takes priority over the

condition of the data inputs and disables the transmitter (See

Transmitter Logic Waveforms - Figure 3).

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 transmitter output level is controlled by an external DC

resistors connected in parallel to the capacitor (low ESR), are

needed to connect the transmitter outputs to the primary of the

coupling transformer.

The main difference between H009 transmitter operation and

MacAir/1553/1760 transmitter operation is the Inhibit function

(TX INHIBIT A / TX INHIBIT B). In H009 operation, when both

the DATA and DATA transmitter inputs are held low or high, the

transmitter output impedance is low, and there is no transmitter

output signal. This function is used to terminate the bus, for a

period of time, in a H009 system. When the TX INHIBIT is pulled

a high impedance state, effectively removing it from the 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 and 4). Since H009 and

MacAir/

1553/1760 bus thresholds are usually different, the

receiver threshold levels for both channels can be set, for either

bus operation, with the Threshold adjust pins.

Grounding the

DATA and DATA threshold adjust pins, for channel A or B, will

set normal 1553 threshold levels of about 0.9Vp-p at 1MHz. By

adding a resistor from each threshold pin to ground the receiver

threshold level can be increased from normal 1553 levels to

normal H009 levels of about 2Vp-p at 1Mhz, or set anywhere in

between.

ACT4462D Dual Transceiver Variable Amplitude Universal

Standard Products

for H009 Specification or MacAir/1553/1760 Bus Operation

October 9, 2007

www.aeroflex.com/Avionics