RCT-433-AS 1 preliminary rev date: 5/21/01 suface mount 433.92 mhz saw-stabilized ook transmitter designed for short-range remote control applications works with ook/ask receivers >600 foot operating range when used with rcr-433-hp receiver 4800 baud data rate the RCT-433-AS is ideal for remote control applications where low- cost and longer range are required. the transmitter operates from a 1.5-12v supply, making it ideal for battery powered applications. the transmitter employs a saw-stabilized oscillator, ensuring accu- rate frequency control for best range performance. output power and harmonic emissions are easy to control, making fcc and etsi com- pliance easy. the manufacturing-friendly smt style package and low-cost make the RCT-433-AS suitable for high volume applications. applications remote keyless entry (rke) remote lighting controls on-site paging asset tracking wireless alarm and security systems long range rfid key features low-cost 1.5-12v operation 5ma current consumption at 3v 0dbm output power at 3v small size: .25? x .4? 4800 baud operation figure 1. mechanical drawing figure 2. suggested pad layout free datasheet http://
RCT-433-AS 2 preliminary rev date: 5/21/01 rating value units power supply and all input pins -0.3 to +15 vdc absolute maximum ratings storage temperature -50 to +100 c soldering temperature (10 sec) 1 350 c characteristic symbol min typ max units notes operating voltage v cc 1.5 3.0 12 vdc none operating current - data=vcc i cc --- 4.5 --- ma @ 3v frequency accuracy tol fc -75 0 +75 khz @ 3v center frequency f c -- 433.92 --- mhz none output power none --- 0 --- dbm @ 3v baud rate - nrz none dc --- 4800 bps none electrical characteristics operating temperature range t op c tbd -20 --- +70 pin name description 1 ant 50 ohm antenna output. the antenna port impedence affects output power and harmonic emissions. an l-c low-pass filter may be needed to suffi- ciently filter harmonic emissions. gnd transmitter ground. connect to ground plane. 3 2 data digital data input. this input is cmos compatible and should be driven with cmos level inputs. 4 pin description notes : 1). hand solder only. the transmitter is not suitable for reflow soldering. vcc pins 4 provides operating voltage for the transmitter. vcc should be bypassed with a .01uf ceramic capacitor and filtered with a 4.7uf tantalum capacitor. noise on the power supply will degrade transmitter noise performance. operating current - data=gnd i cc --- 1.5 --- ua @ 3v free datasheet http://
RCT-433-AS 3 preliminary rev date: 5/21/01 theory of operation ook modulation ook modulation is a binary form of amplitude modulation. when a logical 0 is being sent, the carrier is fully supressed. when a logical 1 is being sent, the carrier is fully on. ook is the modulation method of choice for remote control applications where power consumption and cost are the primary factors. because ook transmitters draw no power when they transmit a 0, they exhibit significantly better power consumption than fsk transmitters. ook data rate is limited by the start-up time of the oscillator. high-q oscillators which have very stable center frequencies take longer to start-up than low-q oscillators. the start-up time of the oscillator deter- mines the maximum data rate that the transmitter can send. saw stabilized the transmitter is basically a negative resistance lc oscillator whose senter frequency is tightly controlled by a saw resonator. saw (surface accoustic wave) resonators are fundamental frequency devices that resonate at frequencies much higher than crystals. data rate the oscillator start-up time is on the order of 40usec, which limits the maximum data rate to 4.8 kbit/sec. power supply the RCT-433-AS is designed to operate from a 1.5- 12v power supply. it is crucial that this power supply be very quiet. the power supply should be bypassed using a 0.01uf low-esr ceramic capacitor and a 4.7uf tantalum capacitor. these capacitors should be placed as close to the power pins as possible. antenna output pin 1 is a 50 ohm antenna output. it will support most antenna types, including printed antennas integrated directly onto the pcb. the performance of the different antennas varies. please refer to the applications note ?antennas 101? for more information on antennas. this applications note also includes information on microstrip trans- mission lines. any time a trace is longer than 1/8th the wavelength of the frequency it is carrying, it should be a 50 ohm microstrip. regardless of the antenna type chosen, the vswr at the antenna port should be <2:1. ideally, the impedence at the antenna port would be 50 ohms resistive. the impedence at the antenna power affects the vswr, power output, and harmonic output of the transmitter. in some cases, the output of the transmitter may need a low-pass lc filter to reduce harmonic emis- sions. check with our technical support department for more information. radiotronix, inc. 1141 se grand suite 118 oklahoma city ok 73129 405-604-3093 free datasheet http://
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