Document
CT1775 Universal MacAir/1553 Dumb RTU Hybrid
PRELIMINARY DATA SHEET
www.aeroflex.com/Avionics FEATURES
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CT1775 Replaces DDC BUS-65201 Includes: - Universal Transceiver - Encoder/decoder - Dual Rank I/O Registers - Fail-safe Timer - Clock Oscillator Simple Controls for Single or Dual Redundant Data Bus Configurations Provides Flags for: - Own Address (With Parity) - Mode Code - Broadcast - Time Out - Valid Word - Sync Type 16 Bit or 8 Bit 3-State - Parallel I/O and Serial Out Wraparound Built-In Test MIL-PRF-38534 Compliant Circuits Available Packaging – Hermetic Metal - 68 Pin, 1.85" x 1.6" x .19" Plug-In Type Package
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DESCRIPTION
The CT1775 Universal MACAIR/1553 Dumb Remote Terminal Unit (RTU) consists of a transceiver, and encoder/decoder, control logic, dual rank I/O registers and internal clock oscillator packaged in a 1.6" x 1.9" hermetic hybrid. It provides all the functions required to interface between a MACAIR (sinusodial) or MIL-STD-1553 (Trapezoidal) serial MUX data bus and a subsystem parallel 3-state data highway. Utilizing several ASIC ICs, the CT1775 provides sufficient handshaking, control and data lines to permit versatile operation as a remote terminal, a bus controller or a bus monitor, in either single or dual redundant data bus configurations. As a transmitter, the CT1775 accepts 8 bit or 16 bit parallel date from the subsystem, and outputs serial Manchester II coded Command, Status or Data words, under subsystem control. As a receiver, it accepts serial MIL-STD-1553 or MACAIR transmissions and transfers all Command, Status and Data words to the 8 bit or 16 bit data highway, under subsystem control. The CT1775 also provides flags to the subsystem when Broadcast, Mode Code, and Own Address (with parity) commands are decoded. The CT1775 contains a terminal fail-safe timeout circuit which flags message lengths exceeding 768µs, and terminates serial data transmission. Wraparound selftest is initiated by a control line which causes the encoder serial output to be connected to the decoder input. The CT1775 provides a serial output of decoded words, thus allowing Command Word look ahead, for the fastest terminal response.
SCDCT1775 Rev B
TX DATA
SHAPING NETWORK
ENCODER AND CONTROL LOGIC REGISTER SERIAL DATA IN REGISTER
CHAN SELECT BDST INHIBIT BROADCAST MODE CODE VALID WORD MANCHESTER VAL CMD WD FAIL-SAFE COMM DATA SYNC RTENABLE PARITY SERIAL DATA OUT BIT STATUS SERIAL DATA OUT REGISTER REGISTER FAILSAFE DRIVER
DRIVER
RX DATA FILTER DECODER AND CONTROL LOGIC
LIMITER
RX DATA
CLOCK GEN CLOCK OUT XTAL MRST DEC RST CLOCK IN RX STROBE 5
CLOCK POWER
DATA SELECT1 DATA SELECT2
TAKE ENA ADDR DATA ADDR IN PAR S/T DSC ADDR SELECT OUT PAR IN
FIGURE 1 – CT1775 BLOCK DIAGRAM
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DATA
SCDCT1775 Rev B ENC ENABLE SYNC SELECT ESC SEND OUT DATA LOAD LOAD DATA1 DATA2 LATCH LATCH DATA1 DATA2 SHAPING NETWORK MANCHESTER T/O D15 (MSB) THRU D0 (LSB)
TX INHIBIT
TX DATA
DRIVER
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VALUES AT NOMINAL POWER SUPPLY VOLTAGES UNLESS OTHERWISE SPECIFIED
PARAMETER Receiver Differential Input Impedance (DC to 1MHz) Differential Input Voltage Input Threshold (Direct Coupled) CMRR (DC to 2MHZ) CMV (DC to 2MHZ) RX STROBE Characteristics Transmitter Differential Output Voltage Direct Coupled (across 145Ω Load) Transformer Coupled (at stub) Output Rise and Fall time Output Noise TX INHIBIT Characteristics Logic IIH, IIL, IOH, IOL VOH VOL VIH VIL Clock VOHC (Internal Clock) VOLC (Internal Clock) VIHC (External Clock) VILC (External Clock) Power Supplies +5V OSC/CLOCK Supply Voltage Tolerances Current Drain +5V Logic Supply Voltage Tolerances Current Drain +15V (or +12V) Supply Voltage Tolerances Current Drain -15V Supply Voltage Tolerances Current Drain Idle 25% Transmit 100% Transmit -12V Supply Voltage Tolerances Current Drain Idle 25% Transmit 100% Transmit Temperature Range Operating (Case) Storage Physical Characteristics Size 68 pin DDIP
SCDCT1775 Rev B
VALUE
UNITS KΩ VP-P VP-P dB V TTL Loads
4 min 40 max 1 typ 40 min ±10 min 1 typ
30 typ 21 typ 130 typ 10 max 1 typ See pin function & loading Table 2.5 min 0.4 max 2.0 min 0.7 max Supply -0.3 min Ground +0.3 min Supply -0.5 min Ground +0.5 min
VP-P VP-P ns mVP-P TTL Loads
V V V V V V V V
±10 8 typ; 13 max ±10 250 max ±5 65 max ±5 65 max 105 max 250 max ±5 65 max 105 max 250 max −55 to +125 −65 to +150
% mA % mA % mA % mA mA mA % mA mA mA °C °C
1.6 x 1.9 x 0.18
in
TABLE 1 – CT1775 SPECIFICATIONS
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GENERAL
As shown in the block diagram of Figure 1, the CT1775 provides all functions required to implement a Dumb Remote Terminal Unit (RTU). It is designed for the greatest flexibility and ease of use. CT1775 can be operated with either an internal or external clock. Simple control lines are provided to interface with either single channel or dual redundant configurations. Control lines are available to implement either on line or off line wraparound built-in test. CT1775 can be configured to perform a parity check on its hard-wired term.