Low Power Driver / Receiver
For MIL-STD-1553 & Macair
■ 1.5 Watt Total Hybrid Dissipation at 25% Transmitting Duty Cycle
■ Monolithic Design
■ Compatible with MIL-STD-1553A/B & Macair A3818, A5232, A5690 & A4905
■ Meets MIL-STD-1553B
■ TTL Compatible
■ Full Military (-55°C to +125°C) Temperature Range
■ Driver / Receiver in a single Package for Space & Weight Savings
■ Filtering on Receiver to Improve S/N Ratio of System
■ Pin for Pin interchangeable with CT3231 Series
■ Packaging – Hermetic Metal Plug-In or Flat Package
• 24 Lead, 1.27" sq. max x .2" Ht Flat package
• 24 Pin, 1.27" sq. max x .175" Ht Plug-In package
The CT3232 Driver section accepts complementary TTL Data at the input, and produces a 30
Volt nominal peak-to-peak differential signal across a 140Ω load at the output. When coupled to the
Data Bus with a 1:1 transformer, isolated on the Data Bus side with two 55.0Ω fault isolation
resistors, and loaded by two 70Ω terminations plus additional receivers, the Data Bus signal
produced is 7.2 Volts nominal peak-to-peak.
When both “DATA” and “DATA” inputs are held low or both are held high, the driver output
becomes a high impedance and is “removed” from the line. In addition, an overriding “INHIBIT”
input provides for removal of the Driver output from the line. A logic “1” applied to the “INHIBIT”
takes priority over the condition of the data inputs and disables the Driver. See Driver Logic
Waveforms, Figure 3.
DATA and DATA inputs must be complementary waveforms, of 50% duty cycle average, with no
gate delays between them.
The CT3232 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 (respectively) of the input beyond a predetermined threshold. See Receiver Logic
Waveforms, Figure 2.
The positive and negative thresholds may be internally set by grounding the appropriate pins, or
externally set with resistors. The pre-set internal thresholds will detect Data Bus signals exceeding
1Volt p-p and ignore signals less than 0.5Volt p-p when used with 1:1 transformer (See Figure 4 for
a suitable transformer and typical connection).
A low level at the STROBE input inhibits the DATA and DATA outputs. If unused, a 2KΩ pull-up to
+5V is recommended.
eroflex Circuit Technology – Data Bus Modules For The Future © SCDCT3232 REV A 6/27/02