19-1700; Rev 3; 4/00 MAX3509 Evaluation Kit Windows 95/98 and DOS are registered trademarks of Microsoft Corp. Component Suppliers table appears at end of EV Kit Manual. Features ♦ Single-Supply Operation ♦ Output Level Range from < 12dBmV to 67dBmV (QPSK) ♦ Gain Programmable in 1dB Steps via Software ♦ Transmit-Disable Mode ♦ Shutdown Mode ♦ Control Software Included ♦ Fully Assembled and Tested Surface-Mount Board Ordering Information PART MAX3509EVKIT *Exposed paddle TEMP. RANGE IC PACKAGE -40°C to +85°C 20 TSSOP-EP* Component List DESIGNATION QTY DESCRIPTION B1−B4 4 Ferrite beads (0603) Murata BLM21P300SPT C1, C4, C5, C8, C9, C11, C19 7 0.1µF ±10% ceramic capacitors (0805) Murata GRM40X7R104K016A C2, C3 2 C6 C7 C10, C18, C21−C24 C12, C20 1000pF ±10% ceramic capacitors (0603) Murata GRM39X7R102K050A 1 10µF ±10%, 16V min tantalum capacitor AVX TAJC106K016 1 4.7µF ±10%, 10V min tantalum capacitor AVX TAJC475K020 6 100pF ±5% ceramic capacitors (0603) GRM40COG101J050A 2 4700pF ±10%, 25V min ceramic capacitors (0805) Murata GRM40X7R472K016A C13−C17 0 Not installed R1 1 49.9Ω ±1% resistor (0805) R2, R5, R6, R7, R9, R13, R14, R18, R30, R32, R34, R35, 36 R3, R37 R4, R33 0 2 2 Not installed 86.6Ω ±1% resistors (0805) 100kΩ ±5% resistors (0805) DESIGNATION QTY R8, R10, R11, R15, R16, R19, R24, R26−R29 DESCRIPTION 11 100Ω ±5% resistors (0805) R12, R38 2 174Ω ±1% resistors (0805) R22, R23 2 0Ω resistors (0805) R25, R31 2 100Ω ±5% resistors (0805) T1 1 Transformer 1:1 M/A-COM ETC1-1T or Minicircuits TC4-1W T2 1 Transformer 1:1 Coilcraft TTWB1A U1 1 MAX3509EUP 20-pin TSSOP U2 1 SN74LVTH244ADBR 20-pin SSOP U3 1 MAX1615EUK-T, 5-pin SOT23-5 IN1, IN2 (two each) 4 1-pin headers JU1−JU7, J10 8 3-pin headers J1, J2 2 SMA edge-mount connectors J3 1 DB25 connector (right angle, female) None 1 MAX3509 software disk None 1 MAX3509 evaluation kit None 1 MAX3509 data sheet None None 1 1 MAX3509 EV kit data sheet MAX3509 errata ________________________________________________________________ Maxim Integrated Products 1 For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. Evaluates: MAX3509 General Description The MAX3509 evaluation kit (EV kit) simplifies evaluation of the MAX3509 CATV upstream amplifier. The kit includes a serial data interface, which can be programmed through the parallel port of a standard PC. Software (Windows® 95/98 and DOS®) is included to facilitate this function. This software allows the user to program both the gain and transmit modes through a simple user interface. Access to the device input and output is provided through 50Ω SMA connectors. The input is matched to 50Ω, while the output circuit includes a minimum-loss pad that increases the load on the output transformer to 75Ω nominal when using 50Ω test equipment. Evaluates: MAX3509 MAX3509 Evaluation Kit Table 1. Jumper Setting Functions JUMPER FUNCTION SHORT PIN 1 TO PIN 2 SHORT PIN 2 TO PIN 3 JU1 Sets the manual control state of TXEN Logic 1 state (VCC3) Logic 0 state (GND) JU2 Sets the manual control state of SHDN Logic 1 state (VCC3) Logic 0 state (GND) JU3 Sets the method of control for TXEN PC port control Manual control through JU1 JU4 Sets the method of control for SHDN PC port control Manual control through JU2 JU5 SCLK input PC port control N/A JU6 SDA input PC port control N/A JU7 CS input PC port control N/A JU10 74LVTH244A buffer enable Disable buffer Enable buffer Quick Start • 0V to 5V pulse generator (transient measurement) The MAX3509 EV kit is fully assembled and factory tested. Follow the instructions in the Connections and Setup section. Note: The output circuit includes a minimum-loss pad that is used to bring the load impedance up to 75Ω. This must be accounted for in all measurements (see Output Circuit section). • Low-noise amplifier with 40dB gain from 5MHz to 100MHz (noise measurement) • Oscilloscope with 200MHz bandwidth Note: The input transformer is supplied to allow differential input drive from a single-ended source. A transformer is not required in the application. Test Equipment Required • Connections and Setup 1) Set the power supply to +9V, and connect it to the pins labeled +9V and GND on the circuit board. Connect a 50Ω signal source to INPUT, and terminate OUTPUT with a spectrum analyzer or network analyzer having a 50Ω input impedance. If using a signal source with a source impedance other than 50Ω, or if a different input impedance is required, be sure to replace resistor R1 with the appropriatevalue resistor. • • DC supply capable of delivering 10V and 500mA of continuous current HP 8648 or equivalent signal source capable of generating 40dBmV up to 200MHz HP 8561E or equivalent spectrum analyzer with a minimum 200MHz frequency range Digital multimeter (DMM) to monitor VCC and ICC, if desired Lowpass filters to attenuate harmonic output of signal sources, if harmonic measurements are desired. Network analyzer, such as the HP 8753D. (May be used to measure gain and harmonic levels if configured with this option; contact test equipment manufacturer.) IBM PC or compatible Male-to-male 25-pin parallel cable, straight through 2 _______________________________________________________________________________________ • • • • • 2) Connect a 25-pin male-to-male cable between the parallel (printer) port of the PC and the 25-pin female connector on the EV kit board. 3) See Table 1 for board jumper settings. 4) Turn on the power supply. Turn on the PC and the test equipment. Set the signal source for -13dBm (34dBmV across a 50Ω load). 5) Run the software program. Detailed Description Using the Software The MAX3509 uses a serial data interface (SDI) to set gain. Some means of communicating with the SDI is required to use the MAX3509 EV kit. A microprocessor, pattern generator, or PC can be used for this function. MAX3509 Evaluation Kit DIRECTORY DOS FILENAME MAX3509.BAS DESCRIPTION QuickBASIC® Source Code DOS READ3509.TXT “Read Me” Text File Windows MAX3509.EXE Windows Executable Windows MAX3509.DLL DLL File for Printer Port Control Windows READWIN3509.TXT “Read Me” Text File Software is included in this EV kit to facilitate the use of a PC. The disk included with the MAX3509 EV kit contains five files. Table 2 shows these files and their appropriate usage. If your PC has Windows 95/98 installed, read the file READWIN3509.TXT for instructions on operation of the MAX3509.EXE file. If your PC does not have Windows 95/98 installed, use the program MAX3509.BAS. Instructions for the QuickBASIC program are found in READ3509.TXT. Input Buffer The input buffer (U2) is a 3.3V 74LVTH244 octal buffer. It provides protection for the PC’s parallel port against potential +9V supply coupling. The buffer can be disabled by moving the shunt to the VCC position (pin 1 and pin 2). This will put the 74LVTH244 output into a high-impedance state. Gain Adjustment The valid gain control word ranges from 0 to 63 (decimal). The nominal change in gain is 1dB per gain state. Gain states are set exclusively by programming the SDI. Refer to the MAX3509 data sheet for details. Shutdown and Transmit Enable Jumpers JU1 through JU4 determine how the shutdown and transmit-enable features are controlled. Pin 2 of each of these jumpers is connected directly to the device. If an external source (such as a modulator chip or microprocessor) is used to control these features, make the connection to pin 2 of the appropriate jumper. Pads are provided on the bottom side of the board (R9 and R14, respectively) for placement of termination resistors, if needed. If manual control of shutdown and transmit enable is desired, shunt pins 2 and 3 of jumper JU4 and pins 2 and 3 of jumper JU3. This will allow SHDN and TXEN to be controlled by JU2 and JU1, respectively. JU2 and JU1 QuickBASIC is a registered trademark of Microsoft Corp. are used to place either +3.3V or ground at SHDN or TXEN. Pin 3 of these jumpers is ground, and pin 1 is +3.3V. Manual Control of Serial Data Interface If using a source other than a PC to drive the serial data interface of the MAX3509 EV kit (such as a digital pattern generator or microprocessor), remove the shunts on jumpers JU5, JU6, and JU7. Access to the serial data interface is available through these jumpers. Termination pads are provided (R2, R5, R6). Solder an appropriate resistor to these pads, if desired. Refer to the MAX3509 data sheet for a description of the serial data interface. Input Circuit The input circuit of the MAX3509 EV kit is configured with a 1:1 transformer (T1) and a 49.9Ω input resistor. This allows the input to be driven with single-ended 50Ω test equipment. The transformer (T1) is used to generate a differential signal, as rated performance is specified with a differential input drive (typically from a differential lowpass filter). Pads are provided for a pair of termination resistors, if needed (R13, R18). If the MAX3509 is to be driven single ended, the input transformer (T1) must be removed and the undriven input connected to ground through a 0.1µF blocking capacitor. Output Circuit The MAX3509 output has two current-feedback amplifiers configured as an instrumentation amplifier. This architecture aids in suppressing second-order distortion (harmonics). To convert to a single-ended output, a 1:1 transformer (T2) is used. Since most test equipment is supplied with a 50Ω termination impedance, a minimum-loss pad is provided on the output of the transformer to increase the load impedance to a nominal 75Ω. This places the proper load on the device, but will also reduce the measured output voltage level by 7.5dB. It is essential to consider this when making any measurements with the EV kit; 7.5dB must be added to all measurements of voltage gain and output voltage level (including noise) to arrive at the correct value for a 75Ω system. Use 75Ω test equipment, if available, and take the following steps: 1) Remove the 50Ω output SMA connector and replace it with a 75Ω connector. 2) Remove R3 and R37 and replace them with a 0Ω resistor or some other type of shunt. 3) Remove R12 and R38. 4) Be sure to use a 75Ω cable. _______________________________________________________________________________________ 3 Evaluates: MAX3509 Table 2. MAX3509 EV Kit Software Evaluates: MAX3509 MAX3509 Evaluation Kit Analysis Harmonic Distortion A filter will be needed to reject the harmonics generated by the signal source. For this example, a lowpass filter with approximately a 25MHz to 35MHz cutoff frequency will be required. This filter will need to reject at least 20dB of signal at 40MHz. Set the 50Ω signal source for 20MHz and -13dBm. Adjust the amplitude to account for the insertion loss in the filter. Verify with the spectrum analyzer that the second and third harmonics generated by the source are suppressed by at least 70dBc. Connect the filter between INPUT of the EV kit and the output of the signal source, making sure the proper terminations are being used for this particular filter. Connect a spectrum analyzer to OUTPUT. Set the center frequency for 40MHz and the span for 50MHz or more. Adjust the reference level so that the fundamental (20MHz tone) is within 10dB to 20dB of the reference level. If the fundamental is less than 10dB below the reference level, the harmonic distortion of the spectrum analyzer may prevent accurate measurement of the distortion. Set the gain state to 50 (approximately 24dB of gain). Measure the level of the fundamental, second, and third harmonics on the spectrum analyzer. These readings have units of dBm. To convert from dBm to dBmV in a 50Ω system, use the following equation: X(dBmV) = Y(dBm) + 47dB (50Ω system) Add 7.5dB to this value to account for the attenuation of the minimum-loss pad, in dBmV, for a 75Ω load. The gain can now be calculated in dB, and the harmonic distortion can be calculated in dBc. Switching Transients To measure the transmit-enable and transmit-disable transients, the TXEN pin will be driven from an external source. No input signal is applied, and the output is viewed on an oscilloscope. Connect OUTPUT to the oscilloscope’s 50Ω input. Set the scope’s time base to 5µs/div and the vertical scale to 5mV/division. Set the pulse generator as follows: Amplitude Duty Cycle Rise/Fall Time Pulse Width Offset 4 5V 50% 100ns 25µs 2.5V Take care not to drive the MAX3509 TXEN pin below 0V or above +5V. Turn on the power supply. Remove the shunt from jumper JU3 (TXEN), and connect the output of the pulse generator to pin 2 of this jumper. Trigger the oscilloscope from the pulse generator using a convenient method. Set the gain control word to 57. A rising- and falling-edge transient should appear on the scope’s CRT. The amplitude of this transient should be less than 100mVp-p. Multiply the value of the measured transient by 2.37 to account for the presence of the minimum-loss pad. The gain may now be changed to show the output transient’s dependence on gain. Output Noise To measure output noise, a spectrum analyzer is used. A postamplifier with less than 10dB noise figure and greater than 40dB gain within the band of interest is needed. With the power supply off, place a 50Ω termination on the input of the EV kit. Turn on the power supply to the MAX3509 EV kit. Using the software, set the device to transmit mode with a gain control word of 50 (approximately 24dB of gain). Connect the output of the postamplifier to the spectrum analyzer and the input to OUTPUT on the EV kit. Set the spectrum analyzer as follows: Center Frequency Span Reference Scale IF Bandwidth 35MHz 60MHz -50dBm 10dB/div 1kHz Power up the postamplifier. If the spectrum analyzer being used has a noise marker function, enable it. The output noise can now be read directly from the spectrum analyzer. Move this marker to 42MHz. Read the value of the noise density from the spectrum analyzer. This noise value is a combination of the output noise of the MAX3509, the gain of the postamp, and the noise figure of the postamp. With the specified noise figure of 10dB, the noise contribution of the postamp may be ignored. The minimum-loss pad reduces the actual measured value by 7.5dB. Use the following equation to arrive at the MAX3509’s output noise: VNOISE = PNOISE + 47dB + 7.5dB + 10 ✕ log (160,000) GAMP _______________________________________________________________________________________ MAX3509 Evaluation Kit VNOISE = MAX3509 output noise in dBmV measured in a 160kHz bandwidth PNOISE = Noise density in dBm/Hz read from the spectrum analyzer GAMP = Gain of the postamplifier in dB If the spectrum analyzer being used does not have a noise marker function, corrections must be made to account for the IF bandwidth used to make the measurement. Consult the user’s manual for your spectrum analyzer for details. Once the correction is made, the value read from the spectrum analyzer can be converted to a noise density (dBm/Hz), and the above formula can be used. Noise can now be measured at various gains. Output noise in transmit-disable mode is insignificant. The MAX3509 evaluation board can serve as a guide for your board layout. Particular attention should be paid to thermal design and to the output network. The MAX3509 package exposed paddle (EP), labeled GND2, conducts heat out of the part and also provides a low-impedance electrical connection. The EP must be attached to the PC board ground plane with a low thermal and electrical impedance contact. Ideally, this would be provided by soldering the backside package contact directly to a top metal ground plane on the PC board. Alternatively, the EP could be connected to a ground plane using an array of plated vias directly below EP. The EV kit incorporates both of these methods. The output circuit that connects OUT+ and OUT- (pins 16 and 17) to the output transformer (T2) should be as symmetrical as possible to reduce second-order distortion. In addition, the inductance of this path should be kept low to minimize gain rolloff at high frequencies. Component Suppliers PHONE FAX AVX SUPPLIER 803-946-0690 803-626-3123 Coilcraft 847-639-6400 847-639-1469 M/A-COM 978-442-5000 978-442-4178 Murata 814-237-1431 814-238-0490 Note: Please indicate that you are using the MAX3509 when contacting these suppliers. _______________________________________________________________________________________ 5 Evaluates: MAX3509 Layout Considerations where: 6 IN2 IN1 R4 100k 15 25 23 24 22 21 20 19 18 R35, OPEN 17 J3 1 R29, 100Ω 13 R19, 100Ω 15 R25, 100Ω 17 R31, 100Ω 13 12 R34, OPEN 11 10 8 7 6 4 5 3 9 20 VCC3 R1 49.9Ω C8 0.1µF 2 R26, 100Ω 4 R27, 100Ω 6 R28, 100Ω 11 R24, 100Ω 8 C19 0.1µF 2 R36 OPEN R7 OPEN INPUT J2 SMA C7 4.7µF B2 B4 B3 2 1 4 2 3 C1 0.1µF U3 MAX1615 R32 OPEN 14 5 1 R30, OPEN 16 VCC3 R33 100k GND +9V C6 10µF B1 R2 OPEN VCC1 IN+ C10 100pF 6 IN- 5 3 5 7 12 R 1 5 , 1 0 0 Ω 9 R16, 100Ω 14 R 1 1 , 1 0 0 Ω 16 R 1 0 , 1 0 0 Ω C9 0.1µF MAX3509 U1 9 10 11 12 13 2 1 15 R9 OPEN R14 OPEN C21 100pF C18 JU6 2 100pF 1 3 2 JU7 1 3 SHDN TXEN OUT- GND2 16 OUT+ GND GND GND GND GND C4 0.1µF 8 1 7 14 VCC1 VCC2 VCC2 CS SDA SCLK 18 19 20 7 GND1 3 C11 0.1µF 4 GND1 18 R 8 , 1 0 0 Ω 1 U2 SN74LVTH244A 19 R13 OPEN JU10 1 23 C2 1000pF C3 1000pF C5 0.1µF T1 1:1 R18 OPEN VCC1 VCC3 VCC2 VCC1 VCC1 VCC2 EXPOSED PADDLE 3 JU5 2 R6 OPEN Figure 1. MAX3509 EV Kit Schematic _______________________________________________________________________________________ JU1 1 2 3 VCC3 C23 1 2 3 100pF JU3 JU2 1 2 3 VCC3 C24 1 2 3 100pF JU4 R5 OPEN T2 C20 4700pF 1:1 C12 4700pF C22 100pF 1 R23 0Ω R22 0Ω R12 R37 174Ω 86.6Ω R3 86.6Ω R38 174Ω 1 2 J1 SMA OUTPUT Evaluates: MAX3509 MAX3509 Evaluation Kit MAX3509 Evaluation Kit Evaluates: MAX3509 1.0" 1.0" Figure 2. MAX3509 EV Kit Component Placement Guide— Component Side Figure 3. MAX3509 EV Kit PC Board Layout—Component Side 1.0" 1.0" Figure 4. MAX3509 EV Kit PC Board Layout—GND Plane Figure 5. MAX3509 EV Kit PC Board Layout—Power Plane _______________________________________________________________________________________ 7 Evaluates: MAX3509 MAX3509 Evaluation Kit 1.0" Figure 6. MAX3509 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. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.