RXM-315-LR_1 ETC2
Document overview
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Technical content
DESCRIPTION
The LR Receiver is ideal for the wireless transfer of serial data, control, or command information in the favorable 260-470MHz band. The receiver’s advanced synthesized architecture achieves an outstanding typical sensitivity of -112dBm, which provides a 5 to 10 times improvement in range over previous solutions. When paired with a compatible Linx transmitter, a reliable wireless link is formed capable of transferring data at rates of up to 10,000bps at distances of up to 3,000 feet. Applications operating over shorter distances or at lower data rates will also benefit from increased link reliability and superior noise immunity. Housed in a tiny reflow-compatible SMD package, the LR Receiver module is footprint-compatible with the popular LC-S Receiver, allowing existing users an instant path to improved range and lower cost. No external components are required (except an antenna), allowing for easy integration, even for engineers without previous RF experience. LR SERIES RECEIVER MODULE DATA GUIDE WIRELESS MADE SIMPLE® Revised 1/25/08 Figure 1: Package Dimensions 0.125" 0.630" LOT 10000 RXM-418-LR-S RF MODULE 0.812" Remote Control Keyless Entry Garage / Gate Openers Lighting Control Medical Monitoring / Call Systems Remote Industrial Monitoring Periodic Data Transfer Home / Industrial Automation Fire / Security Alarms Remote Status / Position Sensing Long-Range RFID Wire Elimination APPLICATIONS INCLUDE Long range Low cost PLL-synthesized architecture Direct serial interface Data rates to 10,000bps Qualified data output No external components needed Low power consumption Wide supply range (2.7 to 5.2VDC) Compact surface-mount package Wide temperature range RSSI and Power-down functions No production tuning
FEATURES
PART # DESCRIPTION TXM-315-LR Transmitter 315MHz TXM-418-LR Transmitter 418MHz TXM-433-LR Transmitter 433MHz RXM-315-LR Receiver 315MHz RXM-418-LR Receiver 418MHz RXM-433-LR Receiver 433MHz EVAL-*-LR Basic Evaluation Kit * = Frequency Receivers are supplied in tubes of 25 pcs.
ORDERING INFORMATION
Figure 7: LR Series Receiver Pinout (Top View) Pin #Name Description 1NC No Connection 2NC No Connection 3NC No Connection 4GND Analog Ground
5 VCCSupply Voltage
6 PDN
Power Down. Pulling this line low will place the receiver into a low-current state. The module will not be able to receive a signal in this state. 7RSSI Received Signal Strength Indicator. This line will supply an analog voltage that is proportional to the strength of the received signal. 8 DATA Digital Data Output. This line will output the demodulated digital data. 9NC No Connection 10NC No Connection 11NC No Connection 12NC No Connection 13NC No Connection 14NC No Connection
15 GND Analog Ground
The LR receiver is a low-cost, high-performance synthesized AM / OOK receiver, capable of receiving serial data at up to 10,000bps. Its exceptional sensitivity results in outstanding range performance. The LR’s compact surface-mount package is friendly to automated or hand production. LR Series modules are capable of meeting the regulatory requirements of many domestic and international applications. THEORY OF OPERATION The LR receiver is designed to recover data sent by an AM or Carrier-Present Carrier-Absent (CPCA) transmitter, also referred to as CW or On-Off Keying (OOK). This type of modulation represents a logic low ‘0’ by the absence of a carrier and a logic high ‘1’ by the presence of a carrier. This modulation method affords numerous benefits. The two most important are: 1) cost-effectiveness due to design simplicity and 2) higher allowable output power and thus greater range in countries (such as the U.S.) that average output power measurements over time. Please refer to Linx Application Note AN-00130 for a further discussion of modulation techniques. The LR receiver utilizes an advanced single-conversion superheterodyne architecture. Transmitted signals enter the module through a 50-ohm RF port intended for single-ended connection to an external antenna. RF signals entering the antenna are filtered and then amplified by an NMOS cascode Low Noise Amplifier (LNA). The filtered, amplified signal is then down-converted to a 10.7MHz Intermediate Frequency (IF) by mixing it with a low-side Local Oscillator (LO). The LO frequency is generated by a Voltage Controlled Oscillator (VCO) locked by a Phase-Locked Loop (PLL) frequency synthesizer that utilizes a precision crystal reference. The mixer stage incorporates a pair of double-balanced mixers and a unique image rejection circuit. This circuit, along with the high IF frequency and ceramic IF filters, reduces susceptibility to interference. The IF frequency is further amplified, filtered, and demodulated to recover the baseband signal originally transmitted. The baseband signal is squared by a data slicer and output to the DATA pin. The architecture and quality of the components utilized in the LR module enable it to outperform many far more expensive receiver products. Data Slicer LNA VCO PLL XTAL 90˚ Limiter Data Out RSSI/Analog 10.7MHz IF Filter Band Select Filter 50Ω RF IN (Antenna) Figure 8: LR Series Receiver Block Diagram DataData CarrierCarrier Figure 9: CPCA (AM) Modulation
A whip-style antenna provides outstanding overall performance and stability. A low-cost whip is can be easily fabricated from a wire or rod, but most designers opt for the consistent performance and cosmetic appeal of a professionally-made model. To meet this need, Linx offers a wide variety of straight and reduced-height whip-style antennas in permanent and connectorized mounting styles. The wavelength of the operational frequency determines an antenna’s overall length. Since a full wavelength is often quite long, a partial 1/2- or 1/4-wave antenna is normally employed. Its size and natural radiation resistance make it well matched to Linx modules. The proper length for a straight 1/4-wave can be easily determined using the adjacent formula. It is also possible to reduce the overall height of the antenna by using a helical winding. This reduces the antenna’s bandwidth, but is a great way to minimize the antenna’s physical size for compact applications. This also means that the physical appearance is not always an indicator of the antenna’s frequency. Linx offers a wide variety of specialized antenna styles. Many of these styles utilize helical elements to reduce the overall antenna size while maintaining reasonable performance. A helical antenna’s bandwidth is often quite narrow and the antenna can detune in proximity to other objects, so care must be exercised in layout and placement. Whip Style Loop Style L =234 FMHz Where:L = length in feet ofquarter-wave length F = operating frequencyin megahertz Specialty Styles A loop- or trace-style antenna is normally printed directly on a product’s PCB. This makes it the most cost-effective of antenna styles. The element can be made self-resonant or externally resonated with discrete components, but its actual layout is usually product specific. Despite the cost advantages, loop-style antennas are generally inefficient and useful only for short-range applications. They are also very sensitive to changes in layout and PCB dielectric, which can cause consistency issues during production. In addition, printed styles are difficult to engineer, requiring the use of expensive equipment, including a network analyzer. An improperly designed loop will have a high SWR at the desired frequency, which can cause instability in the RF stage. Linx offers low-cost planar and chip antennas that mount directly to a product’s PCB. These tiny antennas do not require testing and provide excellent performance in light of their small size. They offer a preferable alternative to the often-problematic “printed” antenna. COMMON ANTENNA STYLES There are literally hundreds of antenna styles and variations that can be employed with Linx RF modules. Following is a brief discussion of the styles most commonly utilized. Additional antenna information can be found in Linx Application Notes AN-00100, AN-00140, and AN-00500. Linx antennas and connectors offer outstanding performance at a low price. ONLINE RESOURCES Latest News Data Guides Application Notes Knowledgebase Software Updates If you have questions regarding any Linx product and have Internet access, make www.linxtechnologies.com your first stop. Our website is organized in an intuitive format to immediately give you the answers you need. Day or night, the Linx website gives you instant access to the latest information regarding the products and services of Linx. It’s all here: manual and software updates, application notes, a comprehensive knowledgebase, FCC information, and much more. Be sure to visit often! www.antennafactor.com The Antenna Factor division of Linx offers a diverse array of antenna styles, many of which are optimized for use with our RF modules. From innovative embeddable antennas to low-cost whips, domes to Yagis, and even GPS, Antenna Factor likely has an antenna for you, or can design one to meet your requirements. www.connectorcity.com Through its Connector City division, Linx offers a wide selection of high-quality RF connectors, including FCC- compliant types such as RP-SMAs that are an ideal match for our modules and antennas. Connector City focuses on high-volume OEM requirements, which allows standard and custom RF connectors to be offered at a remarkably low cost. www.linxtechnologies.com
When working with RF, a clear distinction must be made between what is technically possible and what is legally acceptable in the country where operation is intended. Many manufacturers have avoided incorporating RF into their products as a result of uncertainty and even fear of the approval and certification process. Here at Linx, our desire is not only to expedite the design process, but also to assist you in achieving a clear idea of what is involved in obtaining the necessary approvals to legally market your completed product. In the United States, the approval process is actually quite straightforward. The regulations governing RF devices and the enforcement of them are the responsibility of the Federal Communications Commission (FCC). The regulations are contained in Title 47 of the Code of Federal Regulations (CFR). Title 47 is made up of numerous volumes; however, all regulations applicable to this module are contained in Volume 0-19. It is strongly recommended that a copy be obtained from the Government Printing Office in Washington or from your local government bookstore. Excerpts of applicable sections are included with Linx evaluation kits or may be obtained from the Linx Technologies website, www.linxtechnologies.com. In brief, these rules require that any device that intentionally radiates RF energy be approved, that is, tested for compliance and issued a unique identification number. This is a relatively painless process. Linx offers full EMC pre- compliance testing in our HP / Emco-equipped test center. Final compliance testing is then performed by one of the many independent testing laboratories across the country. Many labs can also provide other certifications that the product may require at the same time, such as UL, CLASS A / B, etc. Once your completed product has passed, you will be issued an ID number that is to be clearly placed on each product manufactured. Questions regarding interpretations of the Part 2 and Part 15 rules or measurement procedures used to test intentional radiators, such as Linx RF modules, for compliance with the technical standards of Part 15, should be addressed to: Federal Communications Commission Equipment Authorization Division Customer Service Branch, MS 1300F2
7435 Oakland Mills Road
Columbia, MD 21046 Phone: (301) 725-1585 Fax: (301) 344-2050 E-Mail: labinfo@fcc.gov International approvals are slightly more complex, although Linx modules are designed to allow all international standards to be met. If you are considering the export of your product abroad, you should contact Linx Technologies to determine the specific suitability of the module to your application. All Linx modules are designed with the approval process in mind and thus much of the frustration that is typically experienced with a discrete design is eliminated. Approval is still dependent on many factors, such as the choice of antennas, correct use of the frequency selected, and physical packaging. While some extra cost and design effort are required to address these issues, the additional usefulness and profitability added to a product by RF makes the effort more than worthwhile. NOTE:Linx RF modules are designed as component devices that require external components to function. The modules are intended to allow for full Part 15 compliance; however, they are not approved by the FCC or any other agency worldwide. The purchaser understands that approvals may be required prior to the sale or operation of the device, and agrees to utilize the component in keeping with all laws governing its use in the country of operation. ACHIEVING A SUCCESSFUL RF IMPLEMENTATION Adding an RF stage brings an exciting new dimension to any product. It also means that additional effort and commitment will be needed to bring the product successfully to market. By utilizing premade RF modules, such as the LR Series, the design and approval process is greatly simplified. It is still important, however, to have an objective view of the steps necessary to ensure a successful RF integration. Since the capabilities of each customer vary widely, it is difficult to recommend one particular design path, but most projects follow steps similar to those shown at the right. In reviewing this sample design path, you may notice that Linx offers a variety of services (such as antenna design and FCC prequalification) that are unusual for a high-volume component manufacturer. These services, along with an exceptional level of technical support, are offered because we recognize that RF is a complex science requiring the highest caliber of products and support. “Wireless Made Simple” is more than just a motto, it’s our commitment. By choosing Linx as your RF partner and taking advantage of the resources we offer, you will not only survive implementing RF, you may even find the process enjoyable. HELPFUL APPLICATION NOTES FROM LINX It is not the intention of this manual to address in depth many of the issues that should be considered to ensure that the modules function correctly and deliver the maximum possible performance. As you proceed with your design, you may wish to obtain one or more of the following application notes, which address in depth key areas of RF design and application of Linx products. These applications notes are available online at www.linxtechnologies.com or by contacting the Linx literature department. DECIDE TO UTILIZE RF RESEARCH RF OPTIONS CHOOSE LINX MODULE ORDER EVALUATION KIT(S) TEST MODULE(S) WITH BASIC HOOKUP INTERFACE TO CHOSEN CIRCUIT AND DEBUG CONSULT LINX REGARDING ANTENNA OPTIONS AND DESIGN LAY OUT BOARD SEND PRODUCTION-READY PROTOTYPE TO LINX FOR EMC PRESCREENING OPTIMIZE USING RF SUMMARY GENERATED BY LINX SEND TO PART 15 TEST FACILITY RECEIVE FCC ID # COMMENCE SELLING PRODUCT Typical Steps For Implementing RF AN-00100 RF 101: Information for the RF Challenged AN-00125 Considerations For Operation Within The 260-470MHz Band AN-00130 Modulation Techniques For Low-Cost RF Data Links AN-00140 The FCC Road: Part 15 From Concept To Approval AN-00150 Use and Design of T-Attenuation Pads AN-00160 Considerations For Sending Data Over a Wireless Link AN-00232 General Considerations For Sending Data With The LC Series AN-00500 Antennas: Design, Application, Performance NOTE APPLICATION NOTE TITLE
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MERLIN, OR 97532 PHONE: (541) 471-6256 FAX: (541) 471-6251 www.linxtechnologies.com U.S. CORPORATE HEADQUARTERS WIRELESS MADE SIMPLE® Linx Technologies is continually striving to improve the quality and function of its products. For this reason, we reserve the right to make changes to our products without notice. The information contained in this Overview Guide is believed to be accurate as of the time of publication. Specifications are based on representative lot samples. Values may vary from lot-to-lot and are not guaranteed. "Typical" parameters can and do vary over lots and application. Linx Technologies makes no guarantee, warranty, or representation regarding the suitability of any product for use in any specific application. It is the customer's responsibility to verify the suitability of the part for the intended application. NO LINX PRODUCT IS INTENDED FOR USE IN ANY APPLICATION WHERE THE SAFETY OF LIFE OR PROPERTY IS AT RISK. Linx Technologies DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL LINX TECHNOLOGIES BE LIABLE FOR ANY OF CUSTOMER'S INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY FROM ANY DEFECTIVE OR NON-CONFORMING PRODUCTS OR FOR ANY OTHER BREACH OF CONTRACT BY LINX TECHNOLOGIES. The limitations on Linx Technologies' liability are applicable to any and all claims or theories of recovery asserted by Customer, including, without limitation, breach of contract, breach of warranty, strict liability, or negligence. Customer assumes all liability (including, without limitation, liability for injury to person or property, economic loss, or business interruption) for all claims, including claims from third parties, arising from the use of the Products. The Customer will indemnify, defend, protect, and hold harmless Linx Technologies and its officers, employees, subsidiaries, affiliates, distributors, and representatives from and against all claims, damages, actions, suits, proceedings, demands, assessments, adjustments, costs, and expenses incurred by Linx Technologies as a result of or arising from any Products sold by Linx Technologies to Customer. Under no conditions will Linx Technologies be responsible for losses arising from the use or failure of the device in any application, other than the repair, replacement, or refund limited to the original product purchase price. Devices described in this publication may contain proprietary, patented, or copyrighted techniques, components, or materials. Under no circumstances shall any user be conveyed any license or right to the use or ownership of such items. Disclaimer © 2008 by Linx Technologies, Inc. The stylized Linx logo, Linx, “Wireless Made Simple”, CipherLinx, and the stylized CL logo are the trademarks of Linx Technologies, Inc. Printed in U.S.A.