CT1815 10MHz Low Level Serial Interface for MIL-STD-1397 Type D Features CIRCUIT TECHNOLOGY Internally set threshold Matched to 50 ohm system impedance power on and off Operates with ±5 volt supplies Power management Accepts synchronous input data Unique Manchester decoder requires no clock Generates one clock per received bit May be used for serial decoding of indefinite word lengths Other Wire and Fiber Optic types available LE X LA ISO 9001 E I NC . C F S A E RO www.aeroflex.com B • • • • • • • • • RTIFIE D General Description The CT1815 is a single hybrid micro-circuit which incorporates a serial encoder, transceiver, and Manchester decoder in one package. The encoder accepts serial NRZ data in conjunction with two synchronous clocks. This data stream is then Manchester encoded and maybe transformer coupled thru an external transformer to a 75 ohm tri-axial cable for transmission through up to 1000 feet of cable. The CT1815 receiver section accepts bipolar Manchester encoded signals and passes level detected signals to the serial decoder. The serial decoder reconstructs an NRZ data stream with derived clock. This allows the data to be processed by our CT2500 monolithic protocol chip for MIL-STD-1397 serial interfaces. All the input and output signals of the CT1815 are completely compatible with the CT2500. The CT1815 has a power management function. A transmitter standby mode is available to reduce the overall power consumption of the CT1815. Aeroflex Circuit Technology is an 80,000ft2 MIL-PRF-38534 certified facility in Plainview, N.Y. XFMR SEC/DATA Input Serial NRZ Data 10 MHz Shift Clock XFMR SEC 20 MHz Gated Clock 1CT:1 Serial Manchester Encoder Envelope Primary Data Output +5V 78Ω Master Reset Encoder Enable Primary Data Output Power Management XFMR SEC ACT15-1031 Power Management External to Hybrid XFMR SEC/DATA Input Decoded Data Envelope Manchester Decoder and Clock Regeneration Data Reconstruction Rx Strobe ClockR Decoded DataR Figure 1 – Block Diagram eroflex Circuit Technology – Data Bus Modules For The Future © SCDCT1815 REV A 6/12/98 Transmission synchronously with a recovered clock. The receiver is designed to meet the MIL-STD-1397 Type D requirements. The CT1815 accepts synchronous NRZ Data in conjunction with two clocks signals. The NRZ data stream is then converted to Manchester code which is transformer coupled to a 75 ohm Tri-axial cable for transmission up to 1000 ft. Electrical Requirements The specification detailed herein encompasses a hybrid Transceiver/Encoder-Decoder designed to meet the requirements of the MIL-STD-1397 Type D. The transmitter may be placed into standby condition. This reduces power consumption by approximately 600mW. Power management is made available via two standard TTL input pins. The Receiver is always active and is not affected by the power management circuitry. The transceiver is transformer coupled to the specified triaxial cable and is screened to the individual test methods of MIL-STD-883 See Figure 1 for Block Diagram. Inputs and Outputs are all Synchronous NRZ DATA STREAMS The transceiver is matched for 75 ohm operation over a wide band of frequencies. This condition is maintained with power on and off. Transformer Isolation The CT1815 is connected with pin 3 and pin 32 to the ACT15-1031 transformer secondary winding. The center tap of the secondary winding is connected to +5 volts. For matching 75Ω load operation, a 78Ω resistor must be placed across the primary winding of the transformer. Reception The CT1815 receiver section accepts a bipolar signal which is level detected and passed to the serial decoder. The decoder section reconstructs the data and strips the clock from the serial stream. An NRZ decoded data stream is then produced Encoder Timing / Transmitter Specification Symbol Parameter / Condition Min Typ Max Unit Encode Timing t1 Input data set-up time 10 40 ns t2 Encode clock set-up time 10 40 ns t3 Encode envelope set-up time 10 40 ns t4 Encode envelope turn-off time 10 35 ns t5 Transmitter activation set-up time 150 ns t6 Transmitter deactivation hold-time 50 ns tw1 20 MHz gated CK pulse width high 20 30 ns tw2 Encoder shift CK pulse width high 45 55 ns Output Signals Va Output amplitude (see Figure 2) T 2.75 3.25 3.75 V Pulse period 97 100 103 ns Ts Width of 1st positive half bit 45 65 ns Te Width of last half bit 47 65 ns T/2 Half pulse period 47 53 ns Tr Pulse rise time 2.0 V/ns Tf Pulse fall time 2.0 V/ns Vs Voltage overshoot 350 mV Tos Offset Voltage 2T after last zero crossing 150 mV Tdtx Delay from 20 MHz clock input to data output on transformer secondary 20 55 ns Zo Output Impedance 75 80 Ω Aeroflex Circuit Technology 70 2 50 SCDCT1815 REV A 6/12/98 Plainview NY (516) 694-6700 Aeroflex Circuit Technology BIT 0 BIT 1 BIT 2 P1 = 50ns ±0.1% P2 = 100ns ±0.1% BIT N t1 NRZ Serial Input t W2 t2 Encoder Shift Clock Input P2 t W1 20 MHz GATED Clock P1 t3 t4 NRZ Envelope 3 t5 t6 Encoder Enable Power Management Pin Tf 2T SCDCT1815 REV A 6/12/98 Plainview NY (516) 694-6700 Transmitter Output 90% Va VS T 90% V US T dTX 10% T/2 10% Tr T Figure 2 Encoder – Transmitter Timing TOS Te 1 st Data BIT 2 nd Data BIT 3 rd Data BIT 4 th Data BIT 5 th Data BIT Manchester II Receiver Data Decoded Data Envelope R X Data t6 t1 t5 t7 t2 Data R t4 t3 CK R t5 Figure 3 Receiver / Decode Timing Symbol Parameter / Condition Min Nom Max Units t1 Envelope delay time - 45 100 nsec t2 Data decode delay - 115 125 nsec t3 Clock low transition delay - 130 - nsec t4 ClockR high time 35 50 65 nsec t5 ClockR low time 35 50 65 nsec t6 Envelope off delay 120 - 270 nsec t7 Receiver strobe enable to input data set-up time 5 - - nsec t8 Receiver strobe disable to input data hold-time 20 - - ? Power Management Functional Table Encoder Enable (Pin 10) Power Management Input (Pin 9) Receiver Status Transmitter Status 0 0 Active Standby X 1 Active Active 1 X Active Active Power management timing see Figure 2. Aeroflex Circuit Technology 4 SCDCT1815 REV A 6/12/98 Plainview NY (516) 694-6700 Functional Description and Pinout Pin # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 No connection No connection XFMR secondary/ RX data input Test Point Test Point Test Point -5 Volts RX strobe Power management input Encoder enable Case/signal GND Case/signal GND Decoded data envelope TP3 test point TP1 test point TP2 test point -5 Volts TP4 test point ClockR No connection Decoded DataR No connection +5 volts +5 volts 10 MHz encoder shift clock NRZ serial input data Encode envelope 28 20 MHz gated clock (encoder) 29 Master reset reset pulse <15 nsec No connection No connection XFMR secondary/ RX DATA input XFMR secondary XFMR primary/ TX DATA output 30 31 32 33 34 Function Load or Drive Low level disables receiver Controls transmitter power consumption in conjunction with pin 10 3 S loads 1 S load Controls transmitter power consumption in conjunction with pin 9 1 S load High after reception of first half bit; goes low after reception of last half bit (normally low in inactive state) Alignment point: no electrical connection permitted Alignment point: no electrical connection permitted Alignment point: no electrical connection permitted 4 S drive Pin Name Aeroflex Circuit Technology Transmitter-receiver I/O pin No connection permitted No connection permitted No connection permitted Alignment point: no electrical connection permitted Reconstructed clock; one clock pulse per input bit received 3 S drive NRZ reconstructed data. Sampled on clockR rising edge 3 S drive One cycle required per data bit. Must be high in first half of bit cell 1 S load Serial input to be Manchester encoded with the 20 MHz gated CK Must be high to enable transmission; must go low before reception of last 20 MHz positive edge to complete transmission Each bit to be encoded requires two positive edges of the 20 MHz CK. These edges must occur at 25ns and 75ns into the bit cell. The end of transmission requires an additional edge in conjunction with a logic low on the encode envelope. tR, tF < 5nsec. Logic low resets encoder 1 S load 1 S load 1 S load 2 S load Transmitter-Receiver I/O pin Secondary isolated winding, same phase as outer conducter Transformer lead for connection to outer conductor of tri-axial 5 SCDCT1815 REV A 6/12/98 Plainview NY (516) 694-6700 Absolute Maximum Ratings Load and Drive Definitions VCC (Pins 23, 24) +7 Volts Max VEE (Pins 7, 17) -7 Volts Max Logic Input Voltage Applied: Logic Low -1.2V @ 10mA Max Logic High +5.5 Volts 1 S load: requires IIL = -2mA max., VIL = 0.8V max IIH = 50µA max., VIH = 2.5V min CIN < 15 pf 1 S drive: IOH = 50µA min., VOH = 2.5V min IOL = -2 mA min., VOL = 0.5V max Damage will not result from cable open circuits or short circuits (on the transformer primary) of the following types: • Line-to-line • Line-to-ground • 120V AC 60Hz common mode signal Power Consumption Current (mA) Typ Max ICC Standby mode 235 305 IEE Standby mode 75 100 ICC 100% Transmission 447 585 IEE 100% Transmission 242 315 Aeroflex Circuit Technology Environmental Parameters Operating Temperature -55°C to +100°C Case Storage Temperature -55°C to +150°C Screened per individual test methods of MIL-STD-883. 6 SCDCT1815 REV A 6/12/98 Plainview NY (516) 694-6700 CIRCUIT TECHNOLOGY Ordering Information Model Number Package Plug-in Package CT1815 Flat Package CT1815FP Plug-In Package Outline 1.200 ±.005 Pin 1 & ESD Designator 1.810 MAX .100 TYP Both Sides .200 .270 ±.010 .100 ±.005 TYP .018 ±.002 DIA .120 ±.010 Both Sides (17 Pins/Side) Flat Package Outline .015 ±.003 .180 MAX .100 ±.005 .400 MIN 1.410 MAX Lead 1 & ESD Designator 1.810 MAX .010 ±.002 Aeroflex Circuit Technology 35 South Service Road Plainview New York 11830 Telephone: (516) 694-6700 FAX: (516) 694-6715 Toll Free Inquiries: 1-(800)THE-1553 Specifications subject to change without notice. Aeroflex Circuit Technology 7 SCDCT1815 REV A 6/12/98 Plainview NY (516) 694-6700