RXM-900-HP3

HIGH-PERFORMANCE RF MODULE RXM-900-HP3-xxx W IRELESS MADE SIMPLE ® HP3 SERIES RECEIVER MODULE DATA GUIDE DESCRIPTION The HP3 RF receiver module offers complete HP SERIES RF RECEIVER compatibility and numerous enhancements 0.780" RXM-900-HP3-SP* over previous generations. The HP3 is designed for the cost-effective, highperformance wireless transfer of analog or 0.236" digital information in the popular 902-928MHz SIP Style band. All HP3 Series modules feature eight 1.950" parallel selectable channels, but versions are HP SERIES RF RECEIVER also available which add serial selection of 100 0.750" RXM-900-HP3-SP* channels. To ensure reliable performance, the receiver employs FM / FSK demodulation and 0.190" an advanced dual-conversion microprocessorSMD Style controlled synthesized architecture. The Figure 1: Package Dimensions receiver is pin- and footprint-compatible with all previous generations, but its overall physical size has been reduced. Both SMD and pinned packages are available. When paired with an HP3 transmitter, a reliable link is created for transferring analog and digital information up to 1,000 feet. (under optimal conditions). As with all Linx modules, the HP3 requires no tuning or additional RF components (except an antenna), making integration straightforward even for engineers without prior RF experience. LOT 10000 Pin Spacing: 0.1" LOT 10000 1.940" FEATURES APPLICATIONS INCLUDE Wireless Networks / Data Transfer 8 parallel / 100 serial (PS Versions) Wireless Analog / Audio user-selectable channels Home / Industrial Automation FM / FSK demodulation for outstanding Remote Access / Control performance and noise immunity Remote Monitoring / Telemetry Exceptional sensitivity (-100dBm typical) Long-Range RFID Wide-range analog capability including MIDI Links audio (50Hz to 28kHz) Voice / Music / Intercom Links RSSI and Power-down lines Precision frequency ORDERING INFORMATION synthesized architecture PART # DESCRIPTION No external RF components required RXM-900-HP3-PPO HP3 Receiver (SIP 8 CH only) Compatible with previous RXM-900-HP3-PPS HP3 Receiver (SIP 8p / 100s CH) HP Series modules RXM-900-HP3-SPO HP3 Receiver (SMD 8 CH only) High data rate RXM-900-HP3-SPS HP3 Receiver (SMD 8p / 100s CH) (up to 56kbps) MDEV-900-HP3-PPS-USB HP3 Development Kit (Pinned Pkg.) Wide supply range (2.8 to 13.0VDC) MDEV-900-HP3-PPS-RS232 HP3 Development Kit (Pinned Pkg.) Direct serial interface MDEV-900-HP3-SPS-USB HP3 Development Kit (SMD Pkg.) Pinned and SMD packages MDEV-900-HP3-SPS-RS232 HP3 Development Kit (SMD Pkg.) Wide temperature range Receivers are supplied in tubes of 10 pcs. (-30°C to +85°C) Revised 1/28/08 ELECTRICAL SPECIFICATIONS Parameter POWER SUPPLY Operating Voltage Supply Current Power-Down Current RECEIVE SECTION Receive Frequency Range Center Frequency Accuracy Channel Spacing First IF Frequency Second IF Frequency Noise Bandwidth Data Rate Analog / Audio Bandwidth Analog / Audio Output Level Data Output: Logic Low Logic High Output Impedance Data Output Source Current Receiver Sensitivity RSSI: Dynamic Range Gain Voltage With No Carrier Spurious Emissions Interference Rejection: FC±1MHz FC±5MHz ANTENNA PORT RF Input Impedance TIMING Receiver Turn-On Time: via VCC via PDN Channel Change Time Max time between transitions ENVIRONMENTAL Operating Temperature Range – -30 – +85 T4 T3 T2 T1 – – – – – – – – 7.0 3.0 1.5 20 mSec mSec mSec mSec 4 4 4 4 4 ROUT – – – 54 57 50 – – – dB dB Ω 4 4 4 60 – – – 70 24 – -57 80 – 1.6 – dB mV/dB V dBm 4 4 4 4 – – 0.0 VCC-0.3 – – -94 – – 17 230 -100 0.5 VCC – – -107 VDC VDC kohms µA dBm 6 6 – 7 8,9 N3DB – – – FC 902.62 -50 – – – – 100 50 0.8 250 34.7 10.7 280 – – 1.1 – 927.62 +50 – – – – 56,000 28,000 2.0 MHz kHz kHz MHz MHz kHz bps Hz VAC 3 4 4 – – 4 5 3 VCC ICC IPDN 2.8 16.0 – 3.0 19.0 5.6 13.0 21.0 10.0 VDC mA µA – 1 2 Designation Min. Typical Max. Units Notes ABSOLUTE MAXIMUM RATINGS Supply Voltage VCC Any Input or Output Pin Operating Temperature Storage Temperature Soldering Temperature -0.3 -0.3 -30 -45 +260°C to +18.0 to VCC to +85 to +85 for 10 seconds VDC VDC °C °C *NOTE* Exceeding any of the limits of this section may lead to permanent damage to the device. Furthermore, extended operation at these maximum ratings may reduce the life of this device. PERFORMANCE DATA These performance parameters are based on module operation at 25°C from a 3.0VDC supply unless otherwise noted. Figure 2 illustrates the connections necessary for testing and operation. It is recommended all ground pins be connected to the ground plane. The pins marked NC have no electrical connection. ANT GND GND GND GND GND GND GND NC CS0 CS1 / SS CLOCK CS2 / SS DATA PDN RSSI MODE VCC AUDIO DATA NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC PC PC PC 5VDC PC Figure 2: Test / Basic Application Circuit TYPICAL PERFORMANCE GRAPHS 3.0 PDN RSSI VOLTAGE (V) 2.5 1 2.0 RX DATA 1.5 2 1.0 -110 CH2 2.00V 500uS Delta 1.920mS -100 -90 -80 -70 -60 -50 -40 CH1 1.00V RF INPUT (dBm) Figure 3: RX Enabled to Valid Data Figure 4: Receiver RSSI 10-6 °C Table 1: HP3 Series Receiver Specifications RX OFF Notes 1. Over the entire operating voltage range. 2. With the PDN pin low. 3. Serial mode. 4. Characterized, but not tested. 5. With 1kHz sine wave @ 115kHz transmitter deviation 6. No load. 7. With 1V output drop. 8. For 10-5 @ 9,600bps. 9. At specified center frequency. Page 2 10-5 RX ON >-35dBm BER 10-4 10-3 -92 -93 -94 1 CH1 500mV 1mS Delta 4.080mS -95 -96 -97 -98 PIN (dBm) -99 -100 -101 -102 Figure 5: Worst Case RSSI Response Time Figure 6: BER vs. Input Power (typical) Page 3 PIN ASSIGNMENTS Pinned Receiver 9 N/C 10 CS0 11 CS1 / SS CLOCK 12 CS2 / SS DATA 13 PDN PIN DESCRIPTIONS Surface-Mount Receiver 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 ANT GND GND GND GND GND GND GND NC CS0 CS1 / SS CLOCK CS2 / SS DATA PDN RSSI MODE VCC AUDIO DATA NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 Pin # Name Equivalent Circuit RF In Description 1 ANT 50Ω 50-ohm RF Input 16 VCC 17 AUDIO 14 RSSI 15 MODE 18 DATA 1 ANT 2 GND 3 GND 4 GND 5 GND 6 GND 7 GND 8 GND 2-8 9 10 GND NC CS0 CS0 25k Analog Ground No Connection Channel Select 0 µ 25k 11 CS1 / SS CLOCK CS1 µ 25k Channel Select 1 / Serial Select Clock Channel Select 2 / Serial Select Data 12 CS2 / SS DATA Figure 7: HP3 Series Receiver Pinout CS2 VCC µ Pin # 1 2-8 9 10 11 Name ANT GND NC CS0 CS1 / SS CLOCK CS2 / SS DATA PDN Description 50-ohm RF Input Analog Ground No Connection Channel Select 0 Channel Select 1 / Serial Select Clock. Channel Select 1 when in parallel channel selection mode, clock input for serial channel selection mode. Channel Select 1 / Serial Select Data. Channel Select 2 when in parallel channel selection mode, data input for serial channel selection mode. 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. Received Signal Strength Indicator. This line will supply an analog voltage that is proportional to the strength of the received signal. Mode Select. GND for parallel channel selection, VCC for serial channel selection Supply Voltage Recovered Analog Output Digital Data Output. This line will output the demodulated digital data. No Connection (SMD only) 19-36 NC 18 DATA 14 RSSI 13 PDN 470k PDN Power Down (Active Low) RSSI Received Signal Strength Indicator 12 15 MODE 25k Mode Select µ 16 VCC VCC Voltage Input 2.8-13V 13 14 RSSI 17 AUDIO 1VP-P Analog Output 15 16 17 18 19-36 Page 4 MODE VCC AUDIO DATA NC 4.7k Digital Data Output SMD Only No Connection Figure 8: Pin Functions and Equivalent Circuits Page 5 THEORY OF OPERATION The HP3 is a high-performance multi-channel, dual-conversion superhet receiver capable of recovering both analog (FM) and digital (FSK) information from a matching HP Series transmitter. FM / FSK modulation offers significant advantages over AM or OOK modulation methods, including increased noise immunity and the receiver’s ability to capture in the presence of multiple signals. This is especially helpful in crowded bands, like that in which the HP3 operates. POWER-UP SEQUENCE As previously mentioned, the HP3 is controlled by an on-board microprocessor. When power is applied, the microprocessor executes the receiver start-up sequence, after which the receiver is ready to receive valid data. The adjacent figure shows the start-up sequence. This sequence is executed when power is applied to the VCC line or when the PDN line is taken high. On power-up, the microprocessor reads the external channel selection lines and sets the frequency synthesizer to the appropriate channel. Once the frequency synthesizer has stabilized, the receiver is ready to accept data. POWER ON Squelch Data Output Pin Parallel Mode Determine Mode Serial Mode Read Channel Selection Inputs Program Freq. Synth To Default CH. 50 Channel Select { MODE CS0 CS1 CS2 4MHz Int. Osc. PLL 24MHz Crystal 10.7MHz BPF RSSI Program Frequency Synthesizer Crystal Oscillator Begins to Operate VCO Quad 34.7M BPF LNA 10.7M BPF IF Amp Digital Data Analog Data Crystal Oscillator Begins to Work Ready for Serial Data Input Determine Squelch State Data Output Pin Determine Squelch State Data Output Pin SAW BPF Cycle Here Until Channel or Mode Change Cycle Here Until More Data Input or Mode Change Limiter 10.7M Discriminator Figure 10: Start-Up Sequence Figure 9: HP3 Series Receiver Block Diagram POWER SUPPLY The HP3 incorporates a precision, low-dropout regulator on-board, which allows operation over an input voltage range of 2.8 to 13 volts DC. Despite this regulator, it is still important to provide a supply that is free of noise. Power supply noise can significantly affect the receiver sensitivity; therefore, providing a clean power supply for the module should be a high priority during design. Vcc TO MODULE 10Ω Vcc IN + The single-ended RF port is matched to 50-ohms to support commonly available antennas, such as those manufactured by Linx. The RF signal coming in from the antenna is filtered by a Surface Acoustic Wave (SAW) filter to attenuate unwanted RF energy. A SAW filter provides significantly higher performance than other filter types, such as an LC bandpass filter. Once filtered, the signal is amplified by a Low Noise Amplifier (LNA) to increase the receiver sensitivity and lower the overall noise figure of the receiver. After the LNA, the signal is mixed with a synthesized local oscillator operating 34.7MHz below the incoming transmission frequency to produce the first Intermediate Frequency (IF). The second conversion and FM demodulation is achieved by a highperformance IF strip that mixes the 34.7MHz first conversion frequency with 24.0MHz from a precision crystal oscillator. The resulting second IF of 10.7MHz is then highly amplified in preparation for demodulation. A quadrature demodulator is used to recover the baseband signal from the carrier. The demodulated waveform is filtered, after which it closely resembles the original signal. The signal is routed to the analog output pin and the data slicer stage, which provides squared digital output via the data output pin. A key feature of the HP3 is the transparency of its digital output, which does not impose balancing or duty-cycle requirements within a range of 100bps to 56kbps. An on-board microcontroller manages receiver functions and greatly simplifies user interface. The microcontroller reads the channel selection lines and programs the on-board synthesizer. This frees the designer from complex programming requirements and allows for manual or software channel selection. The microcontroller also monitors incoming signal strength and squelches the data output when the signal is not strong enough for accurate data detection. 10μF A 10Ω resistor in series with the supply followed by a Figure 11: Supply Filter 10µF tantalum capacitor from VCC to ground will help in cases where the quality of supply power is poor. This filter should be placed close to the module’s supply lines. These values may need to be adjusted depending on the noise present on the supply line. USING THE PDN PIN The Power Down (PDN) line can be used to power down the receiver without the need for an external switch. This line has an internal pull-up, so when it is held high or simply left floating, the module will be active. When the PDN line is pulled to ground, the receiver will enter into a low-current (100 or a timing problem, the receiver will default to serial channel 0. This is useful for debugging as it verifies serial port activity. Page 10 0 902.62 1 902.87 2 903.12 3 903.37 4 903.62 5 903.87 6 904.12 7 904.37 8 904.62 9 904.87 10 905.12 11 905.37 12 905.62 13 905.87 14 906.12 15 906.37 16 906.62 17 906.87 18 907.12 19 907.37 20 907.62 21 907.87 22 908.12 23 908.37 24 908.62 25 908.87 26 909.12 27 909.37 28 909.62 29 909.87 30 910.12 31 910.37 32 910.62 33 910.87 34 911.12 35 911.37 36 911.62 37 911.87 38 912.12 39 912.37 40 912.62 41 912.87 42 913.12 43 913.37 44 913.62 45 913.87 46 914.12 47 914.37 48 914.62 49 914.87 50* 915.12 *See NOTE on previous page. 867.92 868.17 868.42 868.67 868.92 869.17 869.42 869.67 869.92 870.17 870.42 870.67 870.92 871.17 871.42 871.67 871.92 872.17 872.42 872.67 872.92 873.17 873.42 873.67 873.92 874.17 874.42 874.67 874.92 875.17 875.42 875.67 875.92 876.17 876.42 876.67 876.92 877.17 877.42 877.67 877.92 878.17 878.42 878.67 878.92 879.17 879.42 879.67 879.92 880.17 880.42 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 915.37 915.62 915.87 916.12 916.37 916.62 916.87 917.12 917.37 917.62 917.87 918.12 918.37 918.62 918.87 919.12 919.37 919.62 919.87 920.12 920.37 920.62 920.87 921.12 921.37 921.62 921.87 922.12 922.37 922.62 922.87 923.12 923.37 923.62 923.87 924.12 924.37 924.62 924.87 925.12 925.37 925.62 925.87 926.12 926.37 926.62 926.87 927.12 927.37 927.62 = Also available in Parallel 880.67 880.92 881.17 881.42 881.67 881.92 882.17 882.42 882.67 882.92 883.17 883.42 883.67 883.92 884.17 884.42 884.67 884.92 885.17 885.42 885.67 885.92 886.17 886.42 886.67 886.92 887.17 887.42 887.67 887.92 888.17 888.42 888.67 888.92 889.17 889.42 889.67 889.92 890.17 890.42 890.67 890.92 891.17 891.42 891.67 891.92 892.17 892.42 892.67 892.92 Mode Page 11 PROTOCOL GUIDELINES While many RF solutions impose data formatting and balancing requirements, Linx RF modules do not encode or packetize the signal content in any manner. The received signal will be affected by such factors as noise, edge jitter, and interference, but it is not purposefully manipulated or altered by the modules. This gives the designer tremendous flexibility for protocol design and interface. Despite this transparency and ease of use, it must be recognized that there are distinct differences between a wired and a wireless environment. Issues such as interference and contention must be understood and allowed for in the design process. To learn more about protocol considerations, we suggest you read Linx Application Note AN-00160. Errors from interference or changing signal conditions can cause corruption of the data packet, so it is generally wise to structure the data being sent into small packets. This allows errors to be managed without affecting large amounts of data. A simple checksum or CRC could be used for basic error detection. Once an error is detected, the protocol designer may wish to simply discard the corrupt data or implement a more sophisticated scheme to correct it. TYPICAL APPLICATIONS The figure below shows a typical RS-232 circuit using the HP3 Series receiver and a Maxim MAX232. The receiver outputs a serial data stream and the MAX232 converts that to RS-232 compliant signals. The MODE line is grounded so the channels are selected by the DIP switches. VCC VCC 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 ANT GND GND GND GND GND GND GND NC CS0 CS1 / SS CLOCK CS2 / SS DATA PDN RSSI MODE VCC AUDIO DATA NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 C3 4.7uF + C4 4.7uF + INTERFERENCE CONSIDERATIONS The RF spectrum is crowded and the potential for conflict with other unwanted sources of RF is very real. While all RF products are at risk from interference, its effects can be minimized by better understanding its characteristics. Interference may come from internal or external sources. The first step is to eliminate interference from noise sources on the board. This means paying careful attention to layout, grounding, filtering, and bypassing in order to eliminate all radiated and conducted interference paths. For many products, this is straightforward; however, products containing components such as switching power supplies, motors, crystals, and other potential sources of noise must be approached with care. Comparing your own design with a Linx evaluation board can help to determine if and at what level design-specific interference is present. External interference can manifest itself in a variety of ways. Low-level interference will produce noise and hashing on the output and reduce the link’s overall range. High-level interference is caused by nearby products sharing the same frequency or from near-band high-power devices. It can even come from your own products if more than one transmitter is active in the same area. It is important to remember that only one transmitter at a time can occupy a frequency, regardless of the coding of the transmitted signal. This type of interference is less common than those mentioned previously, but in severe cases it can prevent all useful function of the affected device. Although technically it is not interference, multipath is also a factor to be understood. Multipath is a term used to refer to the signal cancellation effects that occur when RF waves arrive at the receiver in different phase relationships. This effect is a particularly significant factor in interior environments where objects provide many different signal reflection paths. Multipath cancellation results in lowered signal levels at the receiver and, thus, shorter useful distances for the link. Page 12 GND Figure 14: HP3 Receiver and MAX232 IC The figure below shows a circuit using the QS Series USB module. The QS converts the data from the receiver into USB compliant signals to be sent to a PC. The MODE line is high, so the module is in Serial Channel Select mode. The RTS and DTR lines are used to load the channels. Application Note AN-00155 shows sample source code that can be adapted to use on a PC. The QS Series Data Guide and Application Note AN-00200 discuss the hardware and software set-up required for QS Series modules. GSHD GSHD 6 GND GND 5 Figure 15: HP3 Receiver and Linx QS Series USB Module The receiver can also be connected to a microcontroller, which will interpret the data and take specific actions. A UART may be employed or an I / O line may be used to continuously monitor the DATA line for a valid packet. The receiver may be connected directly to the microcontroller without the need for buffering or amplification. + C5 4.7uF + 1 2 3 4 5 6 7 8 C1+ V+ C1C2+ C2VT2OUT R2IN MAX232 GND VCC GND T1OUT R1IN R1OUT T1IN T2IN R2OUT 16 15 14 13 12 11 10 9 USB-B 4 GND 3 2 DAT 1 5V GND GND C1 4.7uF + C2 4.7uF DB-9 GND 1 6 2 7 3 4 9 5 GND VCC GND 1 2 3 4 5 6 7 8 USBDP RI USBDM DCD GND DSR VCC DATA_IN SUSP_IND DATA_OUT RX_IND RTS TX_IND CTS 485_TX DTR SDM-USB-QS 16 15 13 12 11 10 9 1 2 3 4 5 6 GN D 7 8 9 10 11 12 13 VCC 14 16 17 18 ANT GND GND GND GND GND GND GND NC CS0 CS1 / SS CLOCK CS2 / SS DATA PDN RSSI MODE VCC AUDIO DATA NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 Page 13 BOARD LAYOUT GUIDELINES If you are at all familiar with RF devices, you may be concerned about specialized board layout requirements. Fortunately, because of the care taken by Linx in designing the modules, integrating them is very straightforward. Despite this ease of application, it is still necessary to maintain respect for the RF stage and exercise appropriate care in layout and application in order to maximize performance and ensure reliable operation. The antenna can also be influenced by layout choices. Please review this data guide in its entirety prior to beginning your design. By adhering to good layout principles and observing some basic design rules, you will be on the path to RF success. The adjacent figure shows the suggested PCB footprint for the module. The actual pad dimensions are shown in the Pad Layout section of this manual. A ground plane (as large as possible) should be placed on a lower layer of your PC board opposite the module. This ground plane can also be critical to the performance of your antenna, which will be discussed later. There should not be any ground or traces under the module on the same layer as the module, just bare PCB. GROUND PLANE ON LOWER LAYER MICROSTRIP DETAILS A transmission line is a medium whereby RF energy is transferred from one place to another with minimal loss. This is a critical factor, especially in highfrequency products like Linx RF modules, because the trace leading to the module’s antenna can effectively contribute to the length of the antenna, changing its resonant bandwidth. In order to minimize loss and detuning, some form of transmission line between the antenna and the module should be used, unless the antenna can be placed very close ( the overall length of the 1/4-wave PLANE VIRTUAL λ/4 radiating element. This is often not practical due to DIPOLE size and configuration constraints. In these instances, a designer must make the best use of the Figure 24: Dipole Antenna area available to create as much ground plane as possible in proximity to the base of the antenna. In cases where the antenna is remotely located or the antenna is not in close proximity to a circuit board, ground plane, or grounded metal case, a metal plate may be used to maximize the antenna’s performance. E λ/4 I λ/4 ANTENNA SHARING In cases where a transmitter and receiver VDD module are combined to form a transceiver, Transmitter 0.1μF it is often advantageous to share a single Module 0.1μF Antenna antenna. To accomplish this, an antenna 0.1μF GND switch must be used to provide isolation 0.1μF between the modules so that the full GND Receiver Module transmitter output power is not put on the 0.1μF sensitive front end of the receiver. There Select are a wide variety of antenna switches that Figure 22: Typical Antenna Switch are cost-effective and easy to use. Among the most popular are switches from Macom and NEC. Look for an antenna switch that has high isolation and low loss at the desired frequency of operation. Generally, the Tx or Rx status of a switch will be controlled by a product’s microprocessor, but the user may also make the selection manually. In some cases, where the characteristics of the Tx and Rx antennas need to be different or antenna switch losses are unacceptable, it may be more appropriate to utilize two discrete antennas. Page 18 5. Remove the antenna as far as possible from potential interference sources. Any frequency of sufficient amplitude to enter the receiver’s front end will reduce system range and can even prevent reception entirely. Switching power supplies, oscillators, or even relays can also be significant sources of potential interference. The single best weapon against such problems is attention to placement and layout. Filter the module’s power supply with a high-frequency bypass capacitor. Place adequate ground plane under potential sources of noise to shunt noise to ground and prevent it from coupling to the RF stage. Shield noisy board areas whenever practical. 6. In some applications, it is advantageous to place the module and antenna away from the main equipment. This can avoid interference problems and allows the antenna to be oriented for optimum performance. Always use 50Ω coax, like RG-174, for the remote feed. CASE GROUND PLANE (MAY BE NEEDED) NUT Figure 25: Remote Ground Plane Page 19 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 ® Whip Style 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. www.linxtechnologies.com • • • • • Latest News Data Guides Application Notes Knowledgebase Software Updates L= 234 F MHz Where: L = length in feet of quarter-wave length F = operating frequency in megahertz 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! Specialty Styles 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. Loop Style 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. www.connectorcity.com Through its Connector City division, Linx offers a wide selection of high-quality RF connectors, including FCCcompliant 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. Page 21 Page 20 LEGAL CONSIDERATIONS 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. 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 FCC prescreening, and 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 Office of Engineering and Technology Laboratory Division 7435 Oakland Mills Road Columbia, MD 21046-1609 Phone: (301) 362-3000 Fax: (301) 362-3290 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. Page 22 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. DECIDE TO UTILIZE RF RESEARCH RF OPTIONS ORDER EVALUATION KIT(S) TEST MODULE(S) WITH BASIC HOOKUP CHOOSE LINX MODULE INTERFACE TO CHOSEN CIRCUIT AND DEBUG CONSULT LINX REGARDING ANTENNA OPTIONS AND DESIGN LAY OUT BOARD In reviewing this sample design path, you may SEND PRODUCTION-READY PROTOTYPE TO LINX FOR EMC PRESCREENING notice that Linx offers a variety of services (such as antenna design and FCC prequalification) that are OPTIMIZE USING RF SUMMARY GENERATED BY LINX unusual for a high-volume component manufacturer. SEND TO PART 15 These services, along with an exceptional level of TEST FACILITY technical support, are offered because we recognize RECEIVE FCC ID # that RF is a complex science requiring the highest caliber of products and support. “Wireless Made COMMENCE SELLING PRODUCT Simple” is more than just a motto, it’s our Typical Steps For commitment. By choosing Linx as your RF partner Implementing RF 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. NOTE AN-00100 AN-00126 AN-00130 AN-00140 AN-00155 AN-00160 AN-00500 APPLICATION NOTE TITLE RF 101: Information for the RF Challenged Considerations For Operation Within The 902-928MHz Band Modulation Techniques For Low-Cost RF Data Links The FCC Road: Part 15 From Concept To Approval Serial Loading Techniques for the HP Series 3 Considerations For Sending Data Over a Wireless Link Antennas: Design, Application, Performance Page 23 WIRELESS MADE SIMPLE ® U.S. CORPORATE HEADQUARTERS LINX TECHNOLOGIES, INC. 159 ORT LANE MERLIN, OR 97532 PHONE: (541) 471-6256 FAX: (541) 471-6251 www.linxtechnologies.com Disclaimer 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. © 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.