TRF7900APW

TRF7900A www.ti.com SWRS031 – OCTOBER 2005 Fully Integrated Analog Front-End Dual Receiver Base Unit for 27-MHz Wireless Mouse and Keyboard Systems • FEATURES • • • • • 23 Discrete Components Intgrated into One Chip – Only External Components are Bypass and Filter Capacitors, and One Crystal RF Tuner, Mixer, Transistors, Passives, Coils, and Ceramic Filter Functionality All on One Chip Integrated Phase Locked Loop 8 User-Selectable Frequencies – Each Channel (Mouse and Keyboard) Can Independently Select Any of the Available Frequencies Internally Generated 6-MHz Clock to Drive USB Microcontroller • • • • High Data Throughput Rate – 5-kHz Square Wave Simultaneously per Channel – 10 kbps Miller Encoded Data I2C Control Interface Received Signal Strength Indicator 5-V Supply Available in 28-Pin TSSOP (PW) Pacakge APPLICATIONS • • • • • • 27-MHz Wireless Mouse and Keyboard Systems Human Interface Devices Wireless Control Remote Control Toys Wireless Headset Remote instrumentation DESCRIPTION The TRF7900A is a dual integrated RF transceiver designed for human-interface devices (HID). Operating at 27 MHz, it integrates multiple components (PLL, RF mixer, simulated SAW filter, tuning circuit, and miscellaneous passive components) to provide frequency selection from 8 discrete channels. This integration lowers component, manufacturing and system costs. USB or PS/2 Power PCB Loop Antenna TPS71533 I2C Control 2 Data Channels 6MHz for uP TRF7900A 12 MHz Crystal MSP430 The TRF7900A simplifies system design by reducing system component count and manual circuit tuning. By integrating the PLL, SAW filter, and RF mixer, the TRF7900A eliminates the manual tuning of RLC circuits required in traditional implementations. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2005, Texas Instruments Incorporated TRF7900A www.ti.com SWRS031 – OCTOBER 2005 The receiver also generates 8 frequencies that can be programmatically selected via the I2C interface bus for both the mouse channel and/or the keyboard channel. Another 6-MHz clock is internally generated to clock the USB microcontroller; this enables a single crystal to be used to supply the clock needs for the receiver channels and the microcontroller. The optimized receiver design enables simultaneous reception on both parallel channels up to 5 kHz (10 kbps Miller encoding) per channel. A receive strength signal indicator register can be read via the I2C bus to determine the signal strength. Correlating the RSSI reading to the packet error rate enables the controller to diagnose the signal and understand the user condition. ORDERING INFORMATION PACKAGED DEVICES PACKAGE TYPE TRF7900APW TSSOP - 28 TRANSPORT MEDIA, QUANTITY Rails, 50 TRF7900APWR TSSOP - 28 Tape and Reel, 2000 ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) VS– to VS+ Supply voltage VI Input voltage VID Differential input voltage Continuous power dissipation VALUE UNIT (1) 5.5 V ±VS± 0.5 V ±2 V See Dissipation Rating Table TJ Maximum junction temperature, any condition (2) 150 °C TJ Maximum junction temperature, continuous operation, long term reliability(3) 125 °C Tstg Storage temperature range (1) (2) -65 to 150 °C Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds 300 °C ESD ratings: Human Body Model 4000 V ESD ratings: Charged Device Model 1500 V ESD ratings: Machine Model 200 V The absolute maximum ratings under any condition is limited by the constraints of the silicon process. Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those specified is not implied. The maximum junction temperature for continuous operation is limited by package constraints. Operation above this temperature may result in reduced reliability and/or lifetime of the device. DISSIPATION RATINGS (1) (2) 2 PACKAGE θJC θJA (1) PW (28) 13.7 56.5 POWER RATING (2) TA≤ 25°C TA = 85°C 1.77 W 708 mW This data was taken using the JEDEC standard high-K test PCB. Power rating is determined with a junction temperature of 125°C. This is the point where distortion starts to substantially increase. Thermal management of the final PCB should strive to keep the junction temperature at or below 125°C for best performance and long term reliability. TRF7900A www.ti.com SWRS031 – OCTOBER 2005 RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) MIN VS– to VS+ Suppy voltage, analog NOM MAX 4.0 UNIT 5.5 V MAX UNIT 100 mA 50 ppm ELECTRICAL CHARACTERISTICS VS = 5 V, TA = 25°C (unless otherwise noted) PARAMETER IO TEST CONDITIONS Output current MIN TYP 100 RF Specifications Precision of required external 12-MHz crystal Channel spacing 50 kHz 26.995 MHz 27.045 MHz 27.095 MHz 27.145 MHz 27.195 MHz 27.295 MHz Optional channel 27.245 MHz Optional channel 26.945 MHz Communication spacing Antenna Input Resistance RO Output resistance, Out_1 and Out_2 DC Differential 27 MHz