19-3615; Rev 0; 3/05 MAX7044 Evaluation Kit The MAX7044 evaluation kit (EV kit) allows for a detailed evaluation of the MAX7044 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 reverse polarity 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 MAX7044EV 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 MAX7044 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. Features ♦ Proven PC Board Layout ♦ Proven Components Parts List ♦ Multiple Test Points Provided on Board ♦ Available in 315MHz or 433.92MHz Optimized Versions ♦ Adjustable Frequency Range from 300MHz to 450MHz* ♦ Fully Assembled and Tested ♦ Can Operate as a Stand-Alone Transmitter with Included Battery *Requires component changes Ordering Information PART TEMP RANGE IC PACKAGE MAX7044EVKIT-315 -40°C to +85°C 8 SOT23-8 MAX7044EVKIT-433 -40°C to +85°C 8 SOT23-8 Component List DESIGNATION QTY 12pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H120J C11, C12 2 220pF ±5%, 50V ceramic capacitors (0603) Murata GRM1885C1H221J 1 10.0pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H100J C14, C15 2 12pF ±5%, 50V ceramic capacitors (0603) Murata GRM1885C1H120J C2 (315MHz) 1 18pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H180J JU1 1 2-pin header Digi-Key S1012-36-ND or equivalent C2, C6 (433MHz) 2 15pF ±5%, 50V ceramic capacitors (0603) Murata GRM1885C1H150J JU2, JU3 2 3-pin headers Digi-Key S1012-36-ND or equivalent L1 (315MHz) 1 2 0.01µF ±10%, 50V ceramic capacitors (0603) Murata GRM188R71H103KA01 27nH ±5% inductor (0603) Coilcraft 0603CS-27NXJB L1 (433MHz) 1 13nH ±5% inductor (0603) Murata LGW18AN13NG00 L3 (315MHz) 1 18nH ±5% inductor (0603) Coilcraft 0603CS-18NXJB L3 (433MHz) 1 11nH ±5% inductor (0603) Coilcraft 0603CS-11NXJB R1 1 5kΩ potentiometer BC Components SM4W502 DESIGNATION QTY C1 (315MHz) 1 C1 (433MHz) C4, C10 C5, C7, C16, C18, C19 0 C6 (315MHz) 1 DESCRIPTION Not installed, capacitors 15pF ±5%, 50V ceramic capacitor (0603) Murata GRM1885C1H150J DESCRIPTION ________________________________________________________________ Maxim Integrated Products 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. 1 Evaluates: MAX7044 General Description Evaluates: MAX7044 MAX7044 Evaluation Kit Component List (continued) DESIGNATION QTY R2 0 DESCRIPTION Not installed, 0Ω resistor (0603), any R3 1 0Ω resistor (0603), any R5 1 47kΩ ±5% resistor (0603), any R6 1 15kΩ ±5% resistor (0603), any R7 1 33kΩ ±5% resistor (0603), any RFOUT 1 SMA connector, top-mount Digi-Key J500-ND Johnson 142-0701-201 1 RP-SMA connector LINX CONREVSMA001 1 SMA connector, top-mount, Digi-Key J500-ND Johnson 142-0701-201 ANTENNA_OUT REF_IN Antenna (315MHz) 0 315MHz 1/4-wave whip antenna, not provided Linx ANT-315-CW-RH Component Suppliers PHONE FAX Coilcraft SUPPLIER 800-322-2645 847-639-1469 Crystek 800-237-3061 941-561-1025 Hong Kong Crystal 852-2412 0121 852-2498 5908 Murata 800-831-9172 814-238-0490 Note: Indicate that you are using the MAX7044 when contacting these component suppliers. Quick Start The following procedure allows for proper device evaluation. Required Test Equipment • One regulated power supply capable of providing +3.0V • One spectrum analyzer such as the Agilent 8562E • One optional ammeter for measuring supply current • One power meter such as the Agilent EPM-441A 2 DESIGNATION QTY Antenna (433MHz) 0 433MHz 1/4-wave whip antenna, not provided Lynx ANT-433-CW-RH CLKOUT, VDD, VSS, DATA_IN 4 Test points Mouser 151-203 or equivalent 1 Crystal, 9.84375MHz Hong Kong Crystals SSL9843750E03FAFZ800 or Crystek 017000 Y1 (433MHz) 1 Crystal, 13.56MHz Hong Kong Crystal SSM1356000E03FAFZ800 or Crystek 017001 BAT1 1 Battery 1 U1 1 MAX7044AKA-T (8-pin SOT23) None 3 Shunts (JU1) Digi-Key S9000-ND or equivalent None 1 MAX7044 EV kit PC board Y1 (315MHz) DESCRIPTION Battery holder MPD BA2032 Coin-cell battery Panasonic BR2032 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 +13dBm 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. Calculate the efficiency. This is done using the following equation: Efficiency = 10^(POUT / 10) / (V x I). 5) For example, for an output of +13dBm, and a current of 14.5mA (at 3.0V), the efficiency is 46%. 6) In order to transmit ASK data, remove the shunts at JU1 and JU2, and connect DATA_IN to an external data source. _______________________________________________________________________________________ MAX7044 Evaluation Kit 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 MAX7044. Detailed Description Power-Down Control The MAX7044 has an automatic shutdown mode that places the device in low-power mode if the DATA input has not toggled for a specific amount of time. The IC draws approximately 40nA (at room temperature) in shutdown mode. In order to transmit continuously, the device has to be placed in test mode by biasing the DATA pin to VDD/2 + 100mV. Jumpers JU1 and JU2 are used to control this mode. Connect the shunt between pins 1 and 2 of JU1 and pins 1 and 2 of JU2. See Table 1 for the jumper function descriptions. Table 1. Jumper Function Table FUNCTION Data Input The MAX7044EV kit transmits ASK data with data rates of up to 100kbps. JU1 and JU2 control whether the MAX7044 transmits CW (JU1 shorted, JU2 pins 1 and 2 connected), or an external data stream (no jumper). 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 0.01µF capacitors). Battery Operation The MAX7044 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 MAX7044 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 the 1/4-wave whip antenna (not supplied). Note that resistor R2 (0Ω) will need to be added. I/O Connections Table 2 lists all I/O connections. See Table 2 for a description. Table 2. I/O Connectors SIGNAL DESCRIPTION RFOUT RF output REF_IN External reference frequency input ANTENNA_OUT VSS VDD Reverse polarity SMA for 1/4-wave antenna Ground 3.0V power input JUMPER STATE JU1 1-2 RF carrier transmit mode DATA_IN Data input JU1 NC Normal OOK operation CLKOUT Crystal frequency divided by 16 JU2 1-2 RF carrier transmit mode JU2 2-3 PA off, PLL ON JU2 NC External OOK data transmit JU3 1-2 External supply operation JU3 2-3 Battery operation For additional information and a list of application notes, consult the www.maxim-ic.com website. _______________________________________________________________________________________ 3 Evaluates: MAX7044 Layout Issues Evaluates: MAX7044 MAX7044 Evaluation Kit C14 12pF C15 12pF Y1 C19 OPEN REF_IN C16 OPEN VDD 1 XTAL2 XTAL1 8 C5 OPEN C18 OPEN VSS 2 VSS VDD VDD 3 R3 0Ω 7 C7 OPEN PAVSS 1 C11 220pF 1 2 JU3 3 C10 0.01µF JU1 R7 33kΩ R6 15kΩ BAT1 U1 R1 VDD VDD 2 MAX7044 3 DATA C4 0.01µF C12 220pF 6 R5 47kΩ L1 C1 4 C2 CLKOUT L3 R2 0Ω RFOUT 1 2 C6 PA ANTENNA_OUT 1 2 5 50Ω OUTPUT CLKOUT * C1 C2 C6 L1 L3 Y1 315MHz 12pF 18pF 15pF 27nH 18nH 9.84375MHz 433MHz 10pF 15pF 15pF 13nH 11nH 13.56MHz * VALUE AFFECTED BY PC BOARD LAYOUT Figure 1. MAX7044 EV Kit Schematic 4 _______________________________________________________________________________________ 1 2 JU2 3 DATA_IN MAX7044 Evaluation Kit Evaluates: MAX7044 Figure 2. MAX7044 EV Kit Component Placement Guide— Component Side Figure 3. MAX7044 EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ 5 Evaluates: MAX7044 MAX7044 Evaluation Kit Figure 4. MAX7044 EV Kit PC Board Layout—Solder Side 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. 6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.