Complies with Directive 2002/95/EC (RoHS) ETSI Compliant I. Product Overview The DR-TXC100-315 and DR-TXC100-433 Evaluation Boards allow for evaluation of the RF performance of the TXC100 300-450MHz Transmitter at 315 MHz and 433.92 MHz, respectively. The board is designed to serve as a standalone evaluation platform or to be incorporated on a user’s design simply by soldering directly to the prototype PCB via standard .025” square header pins. All configurable functions of the TXC100 are accessible for the user to directly interface to any embedded microcontroller design. The DR-TXC100 RF output uses an end launch SMA connector for quick and convenient connection to an external antenna or spectrum analyzer or the connector may be removed and replaced with a λ/4 monopole antenna soldered to the center pin. The output is optimized for two common frequencies of 315MHz and 433.92MHz. The 433.92MHz evaluation board is ETSI compliant. All matching components are accessible for optimization at other frequencies of interest. Evaluation Board Electrical Characteristics Characteristics Max Units 450 MHz ASK Data Rate 100 Kbps FSK Data Rate 20 Kbps Operating Frequency Sym Min fo 300 OOK/ASK/ FSK Modulation Types The DR-TXC100 serves as a guide to PCB layout. Placement and routing can be easily duplicated for quick design-in and proven performance, speeding product time-to-market and reducing design efforts. Typical Peak RF Output Power +10 Standby Current II. Key Features • Operating Frequency Range: 300-450 MHz • Modulation Types: OOK/ASK/FSK • Operation supply voltage: 2.1V - 3.6V • High Date rate: ASK: 100 kbps FSK: 20 kbps • Low current consumption: ASK mode: 7 mA typical FSK mode: 10 mA typical • Low Stand by current: < 1 nA • Adjustable Output power: -10dBm to +10dBm • Adjustable FSK Shift • Programmable Clock Output dBm 1 nA Vdc Supply Voltage Range VDD 2.1 3.6 Operating Temperature Ta -40 +125 o C Reference Crystal Parameters Characteristics Sym Crystal Frequency fc Load Capacitance Cl Min Typical Max fo/32 9 Units MHz 3 pF 10 fF Motional Capacitance Cm Tolerance Tol ±30 www.rfm.com Email: [email protected] ppm RF Monolithics, Inc. 4441 Sigma Road Dallas, Texas 75244 (800) 704-6079 toll-free in U.S. and Canada 1 of 7 III. Schematic Diagram Table 1: Bill of Material for the DR-TXC100 ‡ Ref Des 315MHz Band 433MHz Band C4,C5,C9 100pF 100pF C10* .01uF .01uF C6 DNP DNP C11,C13 1uF 1uF C12,C14 .01uF .01uF C8 220pF 220pF C7 680pF 680pF C1¹ 15pF 3.3pF C3¹ 15pF 12pF C2¹ 22pF 5.6pF L1¹² 27nH 22nH L2¹² 22nH 18nH R1 DNP 0 Ohm R2 0 Ohm DNP Y1 9.84375 ∞ 13.560 ◊ ¹Matching Components ²Use wirewound inductors ONLY for best performance * Install for External Reference ONLY ‡ ETSI COMPLIANT ∞ Hong Kong Crystal P/N SSL9843750E03FAFR800 ◊ Hong Kong Crystal P/N SSM1356000E03FAFR800 2 of 7 IV. Connections and Quick Start Test Equipment Needed: • Spectrum Analyzer • Regulated, Variable Power Supply • Digital Multimeter (DMM) Setup 1) Turn on power supply set to +3V and then turn off. 2) Connect GND lead to any GND pin. 3) Connect +lead of power supply to +input of DMM. 4) Connect COM lead of DMM to VCC of DR-TXC100. 5) Turn DMM to mA setting. 6) Connect the ANT connection (SMA connector) to the spectrum analyzer and set to 315MHz or 433.92MHz with Span = 1MHz. 7) Turn on power supply. The spectrum analyzer should show a peak of about +10dBm at the set frequency (315MHz or 433.92MHz). 8) Observe the current draw on the DMM. 9) Vary the power supply from +2.1V to +3.6V and observe the output power vs. current. V. Jumper Descriptions 3 of 7 Jumpers The DR-TXC100 functions can be tested by configuring the jumper settings or applying external stimulus from a pulse/function generator to pin 2 of the respective jumper. Table 2 shows the jumper designations and associated functions. TABLE 2: Jumper Designations JUMPER JP1 JP2 NOTE: Pin 1 (VCC) denoted by square pad. JP3 Data Pin The TXC100 transmits ASK or FSK data at 100kbps and 20kbps, respectively. JP1 controls whether a logic ‘1’ or logic ‘0’ is applied. For ASK, a logic ‘1’ will turn on the power amplifier. For FSK, a logic ‘1’ will shift the carrier to the higher deviation frequency specified by JP3, JP4, JP5. For ASK, a logic ‘0’ will turn off the power amplifier. For FSK, a logic ‘0’ will shift the output to the fundamental carrier frequency. An external modulating signal can be applied to JP1-2 by removing the jumper and clipping onto the center pin directly and observing the output modulation on the spectrum analyzer. JP4 JP5 JP6 JP7 JP9 Position 1-2 2-3 1-2 2-3 1-2 2-3 1-2 2-3 1-2 2-3 1-2 2-3 1-2 2-3 1-2 2-3 Description Data ‘1’ Data ‘0’ FSK Mode ASK Mode FreqDev(2) ‘1’ FreqDev(2) ‘0' FreqDev(1) ‘1’ FreqDev(1) ‘0' FreqDev(0) ‘1’ FreqDev(0) ‘0' CLK(1) ‘1’ CLK(1) ‘0’ CLK(0) ‘1’ CLK(0) ‘0’ Enabled Power Down Mode Pin Jumper JP2 sets the modulation mode, either ASK or FSK. Deviation Setting The FSK deviation is set by jumpers JP3-JP5. The position of these jumpers sets 1 of 8 possible deviation settings. The maximum deviation is highly dependent on the crystal as is the carrier frequency desired. For 315MHz the max deviation is approximately 55kHz. For 433.92MHz the max deviation is approximately 80kHz. The frequency deviation is affected by the motional capacitance of the crystal. For larger deviations, a crystal with a larger motional capacitance should be used. See Table 3 for jumper deviation settings. TABLE 3: Jumper Deviation Settings JP3 (bit2) 1-2 1-2 1-2 1-2 2-3 2-3 2-3 2-3 JP4 (bit1) 1-2 1-2 2-3 2-3 1-2 1-2 2-3 2-3 JP5 (bit0) 1-2 2-3 1-2 2-3 1-2 2-3 1-2 2-3 Logic 111 110 101 100 011 010 001 000 Description Max Deviation 7/8 x Max Dev 3/4 x Max Dev 5/8 x Max Dev 1/2 x Max Dev 3/8 x Max Dev 1/4 x Max Dev 1/8 x Max Dev Clock Output The clock output frequency is set by jumpers JP6-JP7. The clock can be used for an on-board microcontroller or as an external timing reference. The clock frequency is the crystal frequency divided by 4, 8, and 16. Table 4 shows the jumper setting to configure the clock frequency. TABLE 4: Jumper Settings for Clock Frequency JP6 (bit1) 1-2 1-2 2-3 2-3 JP7 (bit0) 1-2 2-3 1-2 2-3 Logic 11 10 01 00 Description Xtal/16 Xtal/8 Xtal/4 Logic ‘0’ Output 4 of 7 Chip Enable/Standby The chip can be enabled or put into standby mode by setting jumper JP9. In standby mode the current usage drops to <1nA for ultra low power standby. This pin is internally pulled low so removal of the shunt will automatically put the chip in standby mode. To enable the chip place the shunt jumper across JP9(1-2). External Reference Input It is possible to input a custom reference frequency if it is not available as a standard crystal frequency. A test point is provided to apply this frequency from an external source such as a low phase noise RF signal generator. The crystal must be removed to inject this signal. Add .01uF capacitors to C5 and C10 and insert a 0-Ohm, 0603 resistor at C4. 5 of 7 Spectral Shaping Select Spectral Shaping is used to reduce the sideband noise and harmonics associated with fast switching input data signals. To reduce stray inductance the selection for this option is a soldered component. R1 and R2 select either spectral shape biasing or regular power supply biasing. The DR-TXC100 comes with a 0-Ohm resistor soldered into R2, which selects no spectral shaping. Simply remove R2 and solder in a 0-Ohm, 0603 resistor to R1 to select spectral shaping. VI. Recommended Layout Layout considerations should be addressed for two key areas: crystal and RF output. The crystal is a critical part to the accuracy of the output frequency. Its distance from the chip introduces additional parasitic capacitance to the load capacitance of the crystal. This has the effect of reducing the output frequency slightly. The best approach is to put the crystal as close as possible to the chip to avoid adding additional stray capacitance as much as possible. The RF output power is heavily dependent upon the matching circuit components and the distance the signal has to travel. By keeping all components related to the RF output as close as possible minimizes any loss associated with long runs to the output connector. Always use a ground plane under any RF signal to keep the impedance constant. Place decoupling capacitors to GND on all VCC pins. 6 of 7 4441 Sigma Road Dallas, Texas 75244 (800) 704-6079 toll-free in U.S. and Canada Email: [email protected] www.rfm.com www.wirelessis.com © 2006 RF Monolithics, Inc. DR-TXC100 11107 Rev. 3 7 of 7