MAX1472

19-2907; Rev 1; 11/03 MAX1472 Evaluation Kit General Description The MAX1472 evaluation kit (EV kit) allows for a detailed evaluation of the MAX1472 ASK transmitter. It enables testing of the device’s RF performance and requires no additional support circuitry. The RF output uses a 50Ω matching network and an SMA connector for convenient connection to test equipment. A reversepolarity SMA is also included to connect to a 1/4 wave whip antenna. The EV kit can also directly interface to the user’s embedded design for easy data encoding. The MAX1472 EV kit comes in two versions: a 315MHz version and a 433.92MHz version. The passive components are optimized for these frequencies. These components can easily be changed to work at RF frequencies from 300MHz to 450MHz. For easy implementation into the customer’s design, the MAX1472 EV kit also features a proven PC board layout, which can be easily duplicated for quicker time-tomarket. The EV kit Gerber files are available for download at www.maxim-ic.com. o Proven PC Board Layout o Proven Components Parts List o Multiple Test Points Provided On-Board o Available in 315MHz or 433.92MHz Optimized Versions o Adjustable Frequency Range from 300MHz to 450MHz* o Fully Assembled and Tested o Can Operate as a Stand-Alone Transmitter with Included Battery *Requires component changes Features Evaluates: MAX1472 Ordering Information PART MAX1472EVKIT-315 MAX1472EVKIT-433 TEMP RANGE -40°C to +85°C -40°C to +85°C IC PACKAGE 8 SOT23-8 8 SOT23-8 Component List DESIGNATION Antenna (315MHz) QTY 0 DESCRIPTION 315MHz 1/4 wave whip antenna Lynx ANT-315-CW-RH, not installed 433MHz 1/4 wave whip antenna Lynx ANT-433-CW-RH, not installed SMA connector top mount, not installed Digi-Key J500-ND Johnson 142-0701-201 Battery holder MPD BA2032 Coin-cell battery Panasonic BR2032 15pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H150J 7pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H7R0J DESIGNATION C2 (315MHz) QTY 1 DESCRIPTION 22pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H220J 12pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H120J 0.01µF ±10%, 50V ceramic capacitors (0603) Murata GRM188R71H103KA01 680pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H681J Not installed 15pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H150J 10pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H100J 0.47µF +80% - 20%, 16V ceramic capacitor (0603) Murata GRM188F51C474Z Antenna (433MHz) 0 C2 (433MHz) 1 ANTENNA_OUT 1 C3, C10 2 BAT1 Battery 1 1 C4 C5, C16, C18, C19 C6 (315MHz) 1 0 1 C1 (315MHz) 1 C6 (433MHz) 1 C1 (433MHz) 1 C7 1 ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX1472 Evaluation Kit Evaluates: MAX1472 Component List (continued) DESIGNATION C11, C12 QTY 2 DESCRIPTION 220pF ±5%, 50V ceramic capacitors (0603) Murata GRM1885C1H221J 12pF ±5%, 50V ceramic capacitors (0603) Murata GRM1885C1H120J 2-pin headers Digi-Key S1012-36-ND or equivalent Shunts Digi-Key S9000-ND or equivalent 3-pin headers Digi-Key S1012-36-ND or equivalent 27nH ±5% inductor (0603) Coilcraft 0603CS-27NXJB 22nH ±5% inductor (0603) Coilcraft 0603CS-22NXJB 22nH ±5% inductor (0603) Coilcraft 0603CS-22NXJB 15nH ±5% inductor (0603) Coilcraft 0603CS-15NXJB 5kΩ potentiometer BC Components SM4W502 Y1 (433MHz) 1 DESIGNATION R2 R3 R4 REF_IN QTY 0 1 1 1 DESCRIPTION 0Ω resistor (0603), any, not installed 5.1Ω resistor (0603), any 36kΩ ±5% resistor (0603), any RP-SMA connector Lynx CONREVSMA001 SMA connector top mount Digi-Key J500-ND Johnson 142-0701-201 Switch Panasonic EVQ-PJS04K Test points Mouser 151-203 or equivalent MAX1472EKA ICM7555ISA Crystal 9.84375 MHz Hong Kong Crystal SSL9843750E03FAFZ800 or Crystek 017000 Crystal 13.56MHz Hong Kong Crystal SSM1356000E03FAFZ800 or Crystek 017001 MAX1472 EV kit PC board C14, C15 2 JU1, JU4 2 RFOUT 1 JU1 3 SW1 VDD, VSS, ENABLE, DATA-IN U1 U2 1 4 1 1 JU2, JU3 2 L1 (315MHz) L1 (433MHz) L3 (315MHz) L3 (433MHz) R1 1 1 1 1 1 Y1 (315MHz) 1 — 1 Component Suppliers SUPPLIER Coilcraft Crystek Hong Kong Crystal Murata PHONE 800-322-2645 800-237-3061 852-2412 0121 800-831-9172 FAX 847-639-1469 941-561-1025 852-2498 5908 814-238-0490 Connections and Setup This section provides a step-by-step guide to operating the EV kit and testing the device’s functionality. Do not turn on the DC power until all connections are made: 1) Connect a DC supply set to +3.0V, through an ammeter, to the VDD and VSS terminals on the EV kit. Do not turn on the supply. 2) Connect the RF OUT SMA connector to the spectrum analyzer. Set the analyzer to a center frequency of 315MHz (or 433.92MHz) and a span of 1MHz. 3) Turn on the DC supply. The spectrum analyzer should display a peak of about +10dBm at 315MHz (or 433.92MHz). 4) Disconnect the spectrum analyzer and connect the power meter instead. Measure the output power and also the current draw. Quick Start The following procedure allows for proper device evaluation. Required Test Equipment • Regulated power supply capable of providing +3.0V • Spectrum analyzer such as the Agilent 8562E • Optional ammeter for measuring supply current • Power meter such as the Agilent EPM-441A 2 _______________________________________________________________________________________ MAX1472 Evaluation Kit 5) Calculate the efficiency. This is done using the following equation: Efficiency = 10 ^ (Pout / 10) / (V x I) where I is in mA. For example, the efficiency is 46.6% for an output of +11dBm, and a current of 9mA (at 3.0V). Data Input The MAX1472 EV kit transmits ASK data with data rates up to 100kbps. JU2 controls whether the MAX1472 transmits CW (jumper pins 1 and 2 connected), an external data stream (no jumper), or train pulses generated by the ICM7555 timer (jumper pins 2 and 3 connected). JU4 controls whether the ICM7555 data is being generated continuously or at the push of SW1. Evaluates: MAX1472 Layout Issues A properly designed PC board is an essential part of any RF/microwave circuit. On high-frequency inputs and outputs, use controlled-impedance lines and keep them as short as possible to minimize losses and radiation. At high frequencies, trace lengths that are on the order of λ/10 or longer can act as antennas. Keeping the traces short also reduces parasitic inductance. Generally, 1in of a PC board trace adds about 20nH of parasitic inductance. The parasitic inductance can have a dramatic effect on the effective inductance. For example, a 0.5in trace connecting a 100nH inductor adds an extra 10nH of inductance or 10%. To reduce the parasitic inductance, use wider traces and a solid ground or power plane below the signal traces. Also, use low-inductance connections to ground on all GND pins, and place decoupling capacitors close to all VDD connections. The EV kit PC board can serve as a reference design for laying out a board using the MAX1472. REF_IN External Frequency Input For applications where the correct frequency crystal is not available, it is possible to directly inject an external frequency through the REF_IN SMA (not provided). Connect the SMA to a low-phase-noise generator. The addition of C18 and C19 is necessary (use 0.01 µ F capacitors). Battery Operation The MAX1472 EV kit can be powered by an external power supply or by the supplied 3V coin-cell battery. Set jumper JU3 to connect pins 2 and 3 for battery operation. RF Output The MAX1472 EV kit includes two SMA connectors for RF output. RFOUT is a standard SMA and is used to connect the PA output to test equipment. Output is matched to 50Ω. ANTENNA_OUT is a reverse polarity SMA and is used to connect to a 1/4 wave whip antenna . Note that resistor R2 (0Ω) needs to be added. Detailed Description Enable Control The MAX1472 can be controlled externally using the ENABLE connector. The IC draws approximately 1nA (at room temperature) in shutdown mode. Jumper JU1 is used to control this mode. The shunt can be placed between pins 1 and 2 for continuous operation. Remove the JU1 shunt for external control. See Table 1 for jumper function descriptions. I/O Connections Table 2 lists all I/O connections. Table 2. I/O Connectors SIGNAL RFOUT REF_IN ANTENNA_OUT VSS VDD DATA_IN ENABLE RF output External reference frequency input Reverse polarity SMA for 1/4 wave antenna Ground 3.0V power input Data input External power-down control DESCRIPTION Table 1. Jumper Functions JUMPER JU1 JU1 JU2 JU2 JU2 JU3 JU3 JU4 JU4 STATE 1-2 NC 1-2 2-3 NC 1-2 2-3 1-2 NC FUNCTION Normal operation External power-down control RF carrier-transmit mode Transmit pulse-train mode External data transmit External supply operation Battery operation Continuous data generation Data controlled by SW1 For additional information and a list of application notes, consult the Maxim website, www/maxim-ic.com. _______________________________________________________________________________________ 3 MAX1472 Evaluation Kit Evaluates: MAX1472 Figure 1. MAX1472 EV Kit 50Ω OUTPUT AT 315MHz AT 433.92MHz 15pF 7pF 22pF 12pF 15pF 10pF 27nH 22nH 22nH 15nH 9.84375MHz 13.56MHz * C1 C2 C6 L1 L3 Y1 C14 12pF Y1 * C15 12pF C19 OPEN REF_IN 1 2 C16 OPEN *VALUES AFFECTED BY PC BOARD LAYOUT. 1 VDD VSS 1 R1 5kΩ C18 OPEN 2 3 VSS VDD 2 PAVSS U1 3 7 C7 0.47µF 6 VDD 1 JU1 4 PA ENABLE 5 ENABLE TRIGGER 2 TRIGGER DISCHARGE U2 ICM7555 3 VDD SW1 4 JU4 RESET CONTROL VOLTAGE 5 OUTPUT THRESHOLD 6 7 C11 220pF XTAL1 XTAL2 8 C5 OPEN VDD JU3 C10 0.01µF 1 2 3 GND V+ VDD R3 5.1Ω C4 680pF C12 220pF C1 * C2 * MAX1472 DATA L1 * JU2 DATA_IN BAT1 8 L3 * RFOUT R2 0Ω ANTENNA_OUT 1 2 C6 * TRIGGER R4 36kΩ TRIGGER C3 0.01µF Figure 2. MAX1472 EV Kit Circuit Diagram 4 _______________________________________________________________________________________ MAX1472 Evaluation Kit Evaluates: MAX1472 Figure 4. MAX1472 EV Kit PC Board Layout—Top Copper Figure 3. MAX1472 EV Kit Component Placement Guide—Top Silkscreen Figure 5. MAX1472 EV Kit PC Board Layout—Bottom Copper Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 5 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.