19-1670; Rev 0; 7/00 MAX2740 Evaluation Kit Features ♦ Differential Baseband Outputs ♦ +2.7V to +3.3V Single-Supply Operation ♦ SMA Connectors on All Signal Ports Ordering Information PART MAX2740EVKIT TEMP.RANGE IC PACKAGE -40°C to +85°C 48 TQFP-EP* *Exposed Paddle Component List DESIGNATION QTY DESCRIPTION C40 1 2.7pF ±0.1pF ceramic capacitor (0402) Murata GRM36COG2R7B050A C42 1 3pF ±0.1pF ceramic capacitor (0402) Murata GRM36COG030B050A C44 1 2pF ±0.1pF ceramic capacitor (0402) Murata GRM36COG020B050A 0.015µF ±10% ceramic capacitors (0402) Murata GRMX5R153K016A D1 1 BBY 51-03W Siemens tuning diode R2 1 100Ω variable resistor Bourns 3796W Digi-Key 100pF ±5% ceramic capacitors (0402) Murata GRM36COG101J050A R3, R4 2 100Ω ±5% resistors (0402) 7 R5, R8 2 12.1kΩ ±1% resistors (0402) 1 7pF ±0.1pF ceramic capacitor (0402) Murata GRM36COG070B050A DESIGNATION QTY C1 1 10µF ±10% tantalum capacitor AVX TAJC106K016R C2, C10, C14, C18, C20, C21, C32, C33, C35, C36, C37, C38, C43 12 1000pF ±10% ceramic capacitors (0402) Murata GRM36X7R102K050A C3 1 12pF ±5% ceramic capacitor (0402) Murata GRM36COG120J050A 13 C4, C8, C16, C22−C31, C5, C7, C13, C15, C17, C19, C39 C6 C9, C12, C41, C45, C46, C47 6 DESCRIPTION Leave sites open R6, R7, R9, R10 4 2.74kΩ ±1% resistors (0402) R11, R12 2 1.21kΩ ±1% resistors (0402) R13−R18 6 2kΩ ±1% resistors (0402) R19 1 453Ω ±1% resistor (0402) R20 1 15kΩ ±1% resistor (0402) L1, L2, L5 3 220nH inductors Toko LL1608-FSR22J L8, L9 2 8.2nH inductors Toko LL1608-FH8N2K L3 1 Leave site open L10 1 1.8nH inductor Murata LQP10A1N8B00 L11, L12 2 0Ω resistors (0603) ________________________________________________________________ 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: MAX2740 General Description The MAX2740 evaluation kit (EV kit) simplifies testing of the MAX2740 GPS receiver. This kit allows evaluation of the device’s LNA, mixers, variable gain amplifier (VGA), fixed gain amplifier, voltage-controlled oscillator (VCO), and synthesizer. The EV kit provides 50Ω SMA connectors for all signal inputs and outputs. A varactor-based tank circuit is provided for the on-chip VCO and is phase locked with the on-chip phase-locked loop (PLL). Evaluates: MAX2740 MAX2740 Evaluation Kit Component List (continued) DESIGNATION QTY DESCRIPTION U1 1 MAX2740ECM 48-pin TQFP-EP* U2 1 MAX4122EUK SOT23-5 J3−J22 20 SMA connectors (PC mount) Johnson 142-0701-201 or Digi-Key J500-ND JU1−JU4, JU7, JU8, JU9 7 2-pin headers VCC, GND 2 Test points Digi-Key 5000K-ND — 1 MAX2740 EV kit circuit board, Rev. B — 1 MAX2740 data sheet *Note: U1 has an exposed paddle that requires it to be solder attached to the circuit board to ensure proper functionality of the part. Component Suppliers SUPPLIER PHONE FAX AVX 803-946-0690 803-626-3123 Coilcraft 847-639-6400 847-639-1469 Digi-Key 218-681-6674 218-681-3380 Infineon 408-501-6000 408-501-2424 Murata 949-852-2001 949-852-2002 Toko 708-297-0070 708-699-1194 Note: Please indicate that you are using the MAX2740 when contacting these component suppliers. Quick Start The MAX2740 EV kit is fully assembled and factory tested. Follow the instructions in the Connections and Setup section. Table 1 lists the test equipment recommended to verify MAX2740 operation. This list is intended as a guide only; substitutions may be possible. Figure 1 shows the MAX2740 EV kit schematic. Connections and Setup The customer has the option of closing the PLL loop or externally driving the LO. The PLL loop is closed on the assembled EV kit. To externally drive the LO, remove L10 and place C9. A 1440MHz, -10dBm signal is required at the TANK SMA connector. Perform the following steps to evaluate the MAX2740: 1) Verify that jumpers JU1, JU2, and JU7, JU8, JU9 are in place. 2 Table 1. Recommended Test Equipment EQUIPMENT RF Signal Generators (2) DESCRIPTION One HP 8648C or equivalent and one HP 83712A or equivalent. These should be capable of delivering -70dBm to 0dBm of output power in the 10MHz to 2000MHz frequency range. The HP 8648C is required to test the receive signal path, and the HP 83712A is a low-phase noise source for the reference frequency. Power Supply Capable of providing at least 100mA at +2.7V to +3.3V Spectrum Analyzer HP 8561E Balun (2) M/A Com Anzac 96341 Extra Voltage Source For external control of VGA functions 2) Connect VCC and GND. Set the supply voltage to +3.0V. When the power is turned on, the current should be approximately 55mA. 3) For evaluation of the LNA gain, first calibrate the setup for cable losses. Connect the signal generator with 1575.42MHz at -30dBm to LNA_IN. Connect LNA_OUT to the spectrum analyzer. The measured power gain will be approximately 16dB. 4) Repeat the calibration procedure (step 3) for use on the RF mixer. Connect the 1575.42MHz (-30dBm) signal source to the RFMIX_IN+. Connect RFMIX_OUT+ and RFMIX_OUT- through the balun to the spectrum analyzer. At 135MHz, losses due to the Anzac balun are approximately 0.65dB. The measured power gain should be approximately 22dB. If a balun is unavailable, a single-ended measurement of the output can be taken. Terminate the unused output in 50Ω, and add 3dB to the final output power measurement. 5) Repeat the calibration procedure (step 3) for use on the IF mixer. Use the baluns on the input and output to allow a fully differential measurement. Connect IFMIX_IN+ and IFMIX_IN- through one balun to the 135.42MHz (-47dBm) signal source. Connect IFMIX_OUT+ and IFMIX_OUT- through the second balun to the spectrum analyzer. At 135MHz, losses due to the Anzac balun are approximately 0.65dB, and at 15MHz, the losses are approximately 0.3dB. For gain calculation, the attenuation due to _______________________________________________________________________________________ MAX2740 Evaluation Kit PIN = PIN(MEAS) − PLOSS(BALUN AT 135MHz) POUT = POUT(MEAS) + PLOSS(BALUN AT 15MHz) + PLOSS(LOAD) where: 7) The FGA procedure will be similar to the VGA, minus the need for the second voltage source. Repeat the calibration procedure as before (step 3). Connect FGA_IN+ and FGA_IN- through one balun to the 15.42MHz (-43dBm) signal source. Connect FGA_OUT+ and FGA_OUT- through the second balun to the spectrum analyzer. At 15.42MHz, losses due to the Anzac balun are approximately 0.3dB. Calculations are identical to that of the VGA. The measured voltage gain should be approximately 40dB. Adjustments and Control 100 PLOSS(LOAD) = 20log = 32.3dB 4100 Power_Gain = POUT − PIN The measured power gain should be approximately 36dB. 6) To control the VGA gain, connect the second power supply to the nongrounded terminal of jumper JU3, and open jumper JU4. The VGA gain will be evaluated at VGC = 0.5V and 2.5V. It is important to note that the VGA gain and subsequent FGA gain are voltage-gain measurements. Repeat the calibration procedure as before (step 3). Connect VGA_IN+ and VGA_IN- through one balun to the 15.42MHz (-27dBm) signal source. Connect VGA_OUT+ and VGA_OUT- through the second balun to the spectrum analyzer. At 15.42MHz, losses due to the Anzac balun are approximately 0.3dB. For gain calculation, the attenuation due to the 2kΩ load resistor on each output must be taken into account. The total differential gain calculation, assuming two baluns, is: PIN = PIN(MEAS) − PLOSS(BALUN AT 15MHz) POUT = POUT(MEAS) + PLOSS(BALUN AT 15MHz) + PLOSS(LOAD) where: 100 PLOSS(LOAD) = 20log = 32.3dB 4100 Voltage_Gain=POUT − PIN − 6dB The MAX2740 EV kit is configured with a 100kΩ trim pot for setting and adjusting the VGA gain. To use an external supply, remove the 2-pin series and shunt jumpers (JU3 and JU4). Connect the supply directly to the nongrounded terminal of JU3. Detailed Description The following sections cover the EV kit’s circuit blocks in detail. (Refer to the MAX2740 data sheet for additional information.) LNA The LNA is a two-stage amplifier using feedback to set the gain. The circuit requires input and output matching. It is externally biased through the output matching network. RF MIXER The RF mixer is a double-balanced Gilbert cell with local LO drive provided from a low-impedance differential pair. The second RF input is brought out to a separate pin for external decoupling on pin 7. The IF output is delivered through low-output-impedance emitter followers. The input is matched to 50Ω, and the outputs are individually matched to 50Ω (100Ω differential). The mixer is intended to drive a 400Ω SAW filter. IF MIXER The IF mixer is very similar to the RF mixer, except the IF mixer input is fully differential. The emitter follower outputs are intended to drive directly into a high-impedance, differential, 3-pole lowpass filter made up of discrete components. The measured voltage gain at VGC = 2.5V should be approximately 15dB. The gain range should be more than 50dB. _______________________________________________________________________________________ 3 Evaluates: MAX2740 the 2kΩ load resistor on each output must be taken into account. The total differential gain calculation, assuming two baluns, is: Evaluates: MAX2740 MAX2740 Evaluation Kit VGA and FGA The inputs and outputs of both circuits are differential. The VGA has a useful gain-control range of >50dB. The FGA was designed to deliver 40dB of differential gain at the second IF frequency of 15.42MHz. In the application, the FGA differential inputs are received from the VGA outputs through a balanced lowpass filter circuit. The FGA’s differential output is designed to drive a digitizer with a typical load impedance of 4kΩ differential. PC Board Layout/Construction The MAX2740 EV kit can serve as a board layout guide. Keep PC board trace lengths as short as possible to minimize parasitics. Keep decoupling capacitors close to the device, with a low inductance via connection to the ground plane. The GLSOUT signal must not be routed parallel to the REF input to avoid loss of frequency lock due to coupling between the two signals. The MAX2740 EV kit PC board uses 14mil-wide traces for 50Ω traces. The PC board has an 8mil layer profile to the ground plane on FR4, with a dielectric constant of 4.5, and 75mil trace-to-ground-plane spacing. 4 _______________________________________________________________________________________ MAX2740 Evaluation Kit +3VA JU8 RFMIX_OUT+ J20 J19 RFMIX_OUTSMA SMA C35 1000pF JU9 C46 OPEN +3VA_AN C47 OPEN C2 1000pF C33 1000pF 3 C6 7pF L3 NO_LOAD 4 5 6 +3VA 7 C7 100pF JU4 R2 100k JU3 C8 0.015µF 8 IFMIX_OUT- LNA_IN VGA_IN+ GND_1LNA VGA_IN- GND_1LNA GND U1 GND_AMIX VGA_OUT+ MAX2740 FRMIX_IN- VGA_OUTGND AGCON 9 11 +3V_VCO VCC_ANA FGA_IN+ GND_ANA FGA_IN- GND GND C3 12pF C44 2pF C9 OPEN J4 SMA +3VA R10 2.74k R9 2.74k 5 MAX4122 R5 12.1k +3 - U2 2 4 L5 220nH JU7 C20 1000pF C21 1000pF R19 453Ω J5 SMA GLS_OUT GND_DIG 23 GND_DIG GND 22 21 20 REF_IN GLS_OUT 19 UP 18 VCC_DIG DOWN 17 16 C16 0.015µF C17 100pF TANK +3VA GND_VCO L10 1.8nH R20 15k R4 100Ω 15 GND_VCO FGA_OUT+ 14 13 TANK 12 VCC_VCO D1 SIEMENS BBY 51-03W 36 35 34 C31 0.015µF R13 2k C30 0.015µF C29 0.015µF R14 2k 33 32 31 29 28 C27 0.015µF R15 2k C26 0.015µF R16 2k C25 0.015µF R17 2k C23 0.015µF J14 VGA_IN+ SMA J12 VGA_OUT+ SMA J11 VGA_OUTSMA J9 FGA_INSMA C24 0.015µF 25 J15 IFMIX_OUTSMA J10 SMA FGA_IN+ 27 26 J16 SMA IFMIX_OUT+ J13 VGA_INSMA C28 0.015µF 30 +3V_AN 10 C13 100pF 37 IFMIX_OUT+ 2 GND_2LNA LNA_IN J3 SMA GNDIF_MIX 39 IFMIX_IN IFMIX_IN+ VCCRF_MIX GND_2LNA R3 100Ω 40 R11 1.1k VCCIF_MIX R12 1.1k 41 C38 1000pF 45 46 47 LNA_OUT GND 48 C43 1000pF 1 C37 1000pF C42 3pF L9 8.2nH FRMIX_IN+ LNA_OUT +3VA C45 OPEN GND J22 SMA C12 OPEN 42 C41 OPEN GND C40 2.7pF C32 1000pF L11 0Ω L12 0Ω L8 8.2nH 43 IFRMIXN_OUT C5 100pF IFRMIX_OUT- C4 0.015µF 44 FRMIX_OUT GND FGA_OUT- L2 220nH JU2 C39 100pF C10 1000pF FRMIX_OUT+ J2 JU1 + C1 10µF FGAN_OUT 24 J1 IFMIX_OUT+ J18 J17 IFMIX_OUTSMA SMA 38 IFMIXN_IN VCC J21 SMA +3VA_VCO IFMIX_IN- L1 220nH +3VA Evaluates: MAX2740 +3VA J8 SMA FGA_OUT+ C22 0.015µF R18 2k J6 SMA REF_IN J7 SMA FGA_OUT_ C19 100pF R8 12.1k C18 1000pF R6 2.74k C14 1000pF R7 2.74k C15 100pF Figure 1. MAX2740 EV Kit Schematic _______________________________________________________________________________________ 5 Evaluates: MAX2740 MAX2740 Evaluation Kit 1.0" 1.0" Figure 2. MAX2740 EV Kit PC Board Layout—Component Side Figure 3. MAX2740 EV Kit PC Board Layout—Ground Plane 1.0" Figure 4. MAX2740 EV Kit PC Board Layout—Power Plane 6 _______________________________________________________________________________________ MAX2740 Evaluation Kit Evaluates: MAX2740 NOTES _______________________________________________________________________________________ 7 Evaluates: MAX2740 MAX2740 Evaluation Kit NOTES 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.