TXM-315-LR

TXM-315-LR ETC2

Document overview

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Technical content

DESCRIPTION

The LR Series transmitter is ideal for the cost- effective wireless transfer of serial data, control, or command information in the favorable 260-470MHz band. When paired with a compatible Linx receiver, 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. The transmitter’s synthesized architecture delivers outstanding stability and frequency accuracy and minimizes the affects of antenna pulling. Housed in a tiny reflow-compatible SMD package, the transmitter requires no external components (except an antenna), which greatly simplifies integration and lowers assembly costs. LR SERIES TRANSMITTER MODULE DATA GUIDE WIRELESS MADE SIMPLE® Revised 1/28/08 Figure 1: Package Dimensions 0.360" 0.500" 0.130" Typ. TXM-418-LR RF MODULE LOT 2000 „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 „No external RF components needed „Low power consumption „Low voltage (2.1 to 3.6VDC) „Compact surface mount package „Wide temperature range „Power-down function „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 Transmitters are supplied in tubes of 50 pcs.

ORDERING INFORMATION

Figure 5: LR Series Transmitter Pinout (Top View) Pin #Name Description 1GND Analog Ground 2DATA Digital Data Input 3GND Analog Ground 4LADJ/VCC Level Adjust. This line can be used to adjust the output power level of the transmitter. Connecting to VCCwill give the highest output, while placing a resistor to VCCwill lower the output level (see Figure 4 on Page 3).

5 ANT50-ohm RF Output

6 GND Analog Ground

8 PDN

Power Down. Pulling this line low will place the transmitter into a low-current state. The module will not be able to transmit a signal in this state. PIN DESCRIPTIONS MODULE DESCRIPTION The LR transmitter is a low-cost, high-performance synthesized ASK / OOK transmitter, capable of sending serial data at up to 10,000bps. Because the transmitter is completely self-contained, requiring an antenna as the only additional RF component, application is extremely straightforward and assembly and testing costs are reduced. When combined with an LR Series receiver, a reliable serial link is formed capable of transferring data over line-of-site distances of up to 3,000 feet. The LR is housed in a compact surface-mount package that integrates easily into existing designs and is equally friendly to prototyping and volume production. The module’s low power consumption makes it ideal for battery-powered products. The transmitter is compatible with many other Linx receiver products, including the LC, LR, KH, and OEM product families. For applications where range is critical, the LR receiver is the best choice due to its outstanding sensitivity. LR Series modules are capable of meeting the regulatory requirements of domestic and international applications. THEORY OF OPERATION The LR Series transmitter is designed to generate 1mW of output power into a 50-ohm single-ended antenna while suppressing harmonics and spurious emissions to within legal limits. The transmitter is comprised of a VCO locked by a frequency synthesizer that is referenced to a high precision crystal. The output of the VCO is amplified and buffered by an internal power amplifier. The amplifier is switched by the incoming data to produce a modulated carrier. The carrier is filtered to attenuate harmonics and then output to free space via the 50-ohm antenna port. The synthesized topology makes the module highly immune to the effects of antenna port loading and mismatch. This reduces or eliminates frequency pulling, bit contraction, and other negative effects common to low-cost transmitter architectures. It also allows for reliable performance over a wide operating temperature range. Like its companion LR Series receiver, the LR Series transmitter delivers a significantly higher level of performance and reliability than the LC Series or other SAW-based devices, yet remains very small and cost-effective. PLLVCOPA XTAL DATA PDN RF OUT Figure 6: LR Series Transmitter Block Diagram *CAUTION* This product incorporates numerous static-sensitive components. Always wear an ESD wrist strap and observe proper ESD handling procedures when working with this device. Failure to observe this precaution may result in module damage or failure.

The module does not have an internal voltage regulator; therefore it requires a clean, well-regulated power source. While it is preferable to power the unit from a battery, it can also be operated from a power supply as long as noise is less than 20mV. Power supply noise can affect the transmitter modulation; therefore, providing a clean power supply for the module should be a high priority during design. A 10Ωresistor in series with the supply followed by a 10µF tantalum capacitor from V CCto ground will help in cases where the quality of the supply is poor. Note that the values may need to be adjusted depending on the noise present on the supply line. TRANSMITTING DATA Once a reliable RF link has been established, the challenge becomes how to effectively transfer data across it. While a properly designed RF link provides reliable data transfer under most conditions, there are still distinct differences from a wired link that must be addressed. Since the LR Series modules do not incorporate internal encoding or decoding, a user has tremendous flexibility in how data is handled. If you want to transfer simple control or status signals, such as button presses or switch closures, and your product does not have a microprocessor on board, or you wish to avoid protocol development, consider using an encoder and decoder IC set. These chips are available from a range of manufacturers, including Linx. They take care of all encoding and decoding functions and generally provide a number of data pins to which switches can be directly connected. In addition, address bits are usually provided for security and to allow the addressing of multiple units independently. These ICs are an excellent way to bring basic remote control / status products to market quickly and inexpensively. Additionally, it is a simple task to interface with inexpensive microprocessors, such as the Microchip PIC, or one of many IR, remote control, or modem ICs. It is always important to separate what types of transmissions are technically possible from those that are legally allowable in the country of intended operation. While the LR Series is ideally suited to the long range transfer of control and command information, it can also be used with great success for the transfer of true variable data such as temperature, pressure, or sensor data. However, the 260 - 470MHz band in which the module operates is regulated by Part 15, Section 231 of the FCC regulations. Many types of transmissions, especially those involving automatic transmissions or variable data, may need to be periodic. You may wish to review Application Notes AN-00125 and AN-00140 along with Part 15, Section 231 of the FCC regulations for further details on acceptable transmission content in the Unites States. Another area of consideration is that of data structure or protocol. The data should be formatted in a predictable way and should be able to deal with errors due to interference. This will ensure that the data is received and interpreted correctly. If you are not familiar with the considerations for sending serial data in a wireless environment, you will want to review Application Note AN-00160. THE DATA INPUT The CMOS-compatible data input on Pin 2 is normally supplied with a serial bit stream from a microprocessor or encoder, but it can also be used with standard UARTs. When a logic ‘1’ is present on the DATA line and the PDN line is high, then the Power Amplifier (PA) will be activated and the carrier frequency will be sent to the antenna port. When a logic ‘0’ is present on the DATA line or the PDN line is low, the PA is deactivated and the carrier is fully suppressed. The DATA line should always be driven with a voltage that is common to the supply voltage present on Pin 7 (V CC). The DATA line should never be allowed to exceed the supply voltage, as permanent damage to the module could occur. USING THE PDN PIN The transmitter’s Power Down (PDN) line can be used to power down the transmitter without the need for an external switch. It allows easy control of the transmitter’s state from external components, such as a microcontroller. By periodically activating the transmitter, sending data, then powering down, the transmitter’s average current consumption can be greatly reduced, saving power in battery operated applications. The PDN line does not have an internal pull-up, so it will need to be pulled high or tied directly to V CCto turn on the transmitter. The pull-up should be a minimum of 30μA (10kΩor less). When the PDN line is pulled to ground, the transmitter will enter into a low-current (<5nA) power-down mode. When in this mode, the transmitter will be completely off and cannot perform any function.Note: The voltage on the PDN line should not exceed V CC . When used with a higher voltage source, such as a 5V microcontroller, an open collector line should be used or adiode placed in series with the control line (anode toward the module). Either methodavoids damage to the module by preventing 5V from being placed on the PDN line whileallowing the line to be pulled low. USING LADJ The Level Adjust (LADJ) line allows the transmitter’s output power to be easily adjusted for range control, lower power consumption, or to meet legal requirements. This is done by placing a resistor between V CCand LADJ. The value of the resistor determines the output power level. When LADJ is connected to VCC, the output power and current consumption will be at its maximum. Figure 4 on Page 3 shows a graph of the output power vs. LADJ resistance. This line is very useful during FCC testing to compensate for antenna gain or other product-specific issues that may cause the output power to exceed legal limits. A variable resistor can be temporarily used so that the test lab can precisely adjust the output power to the maximum level allowed by law. The variable resistor’s value can be noted and a fixed resistor substituted for final testing. Even in designs where attenuation is not anticipated, it is a good idea to place a resistor pad connected to LADJ and V CCso that it can be used if needed. For more sophisticated designs, LADJ can be also controlled by a DAC or digital potentiometer to allow precise and digitally variable output power control. 10Ω 10μF Vcc IN Vcc TO MODULE Figure 7: Supply Filter

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

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 LEGAL CONSIDERATIONS 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

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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.