19-0409; Rev 1; 3/07 MAX3654 Evaluation Kit The MAX3654 evaluation kit (EV kit) is a factoryassembled printed circuit board (PCB) that provides two circuit versions—optical input and electrical input. The optical circuit includes the photodiode bias circuitry, an op amp for feed-forward AGC operation, and a balun for single-ended 75Ω output. Through-hole pads are provided to attach a triplexer analog photodiode. It is important to select a photodiode with capacitance and inductance in the anode and cathode connections as symmetric as possible for optimum linearity. The electrical circuit is normally configured with a 50Ω input for use with conventional test and measurement equipment and a 75Ω output. The 75Ω output can be connected to 50Ω test and measurement equipment using a minimum loss pad. If desired, the MAX3654 input can also provide a 75Ω input by replacing R12 and R13 with 25Ω resistors. _________________________ Features ♦ Fully Assembled and Tested ♦ Optical and Electrical Inputs ♦ Automatic Gain Control _______________Ordering Information PART TEMP RANGE MAX3654EVKIT -40°C to +85°C IC-PACKAGE 16 QFN __________________________________________________ Evaluation Component List DESIGNATION C1, C2, C4, C5, C19–C22 C3, C7, C8, C9, C12, C16, C17, C23, C24, C27, C29 C6, C10, C11, C25, C26 QTY DESCRIPTION C13, C14, C28 3 R6, R18 R2 R3, R4, R5, R16, R17 R1, R21 2 1 1μF 10V, ±10% min ceramic capacitors 33μF 10V, ±20% min tantalum capacitors 1.62kΩ ±1% resistors (0402) 10Ω ±1% resistor (0402) 6 100kΩ ±1% resistors (0402) 2 R7, R19 8 0.001μF ±10% ceramic capacitors (0402) 11 0.1μF ±5% ceramic capacitors (0603) DESIGNATION QTY DESCRIPTION J2, J4 2 J3 1 TP1–TP13 JU1–JU3, JU5, JU6 13 BNC 75Ω, Edge Mount Trompeter UCBJE20-1 SMA connector, tab contact, Johnson, 142-0701-851 Test Points 5 2-pin headers, 0.1in centers L1, L5 2 L2, L6 2 U1, U3 2 MAX3654ETE+ U2, U4 2 MAX4240EUK 1kΩ ±1% resistors (0402) U5 0 2 2.43kΩ ±1% resistors (0402) U6 1 R9, R15 2 20kΩ ±1% resistors (0402) R12, R13 R8, R20 R22 2 2 1 12.1Ω ±1% resistors (0402) 6.04kΩ ±1% resistors (0402) open (0402) U7, U8 2 Photodiode not supplied Balun Pulse Engineering CX2039 Balun Pulse Engineering CX2038 5 Bead, Murata BLM15HD182SN1 (0402) 10μH inductor, TDK MLF1608E100K (0603) __________________________________________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. Evaluates: MAX3654 ________________General Description Evaluates: MAX3654 MAX3654 Evaluation Kit _____________Component Suppliers SUPPLIER PHONE WEBSITE AVX 803-448-9411 www.avxcorp.com Pulse Engineering 858-674-8100 www.pulseeng.com Murata 770-436-1300 www.murata.com Note: Please indicate that you are using the MAX3654 when contacting these component suppliers. ________________________Quick Start Optical Evaluation 1) Attach triplexer photodiode to IN+ and IN- of the MAX3654. The cathode normally connects to IN+. The photodiode case should be grounded to the most convenient ground via. Make certain that the anode and cathode leads are symmetric in length and orientation, lead lengths should normally be about 5mm. 2) Set JU2 to R4 to manually adjust the gain with an input from 0 to 1.4V on TP3. 3) Leave JU3 open for minimum hysteresis. 4) Set JU1 to R8 to enable the output signal. 5) Connect the signal output at J2 to a 75Ω spectrum-analyser input. A minimum loss pad may also be used to connect J2 to 50Ω test equipment. 6) Connect a +5V supply to the VCC terminal, TP1 and ground to the GND terminal, TP2. 7) Connect the photodiode bias supply to TP13. Typically use +12V bias supply, or as required by the photodiode. Electrical Evaluation 1) Connect a 50Ω signal source to IN at J3. Set the input signal level to PIN = -18dBm, so that the voltage on 50Ω produces the maximum input level of 1.6mAP-P. 2) Connect the RF output at J4 to a 75Ω spectrum analyser input. A minimum loss pad may also be used to connect J4 to 50Ω test equipment. 3) Leave JU6 open for minimum hysteresis. 4) Set JU5 to R20 to enable output. 5) Connect a +5V supply to the VCC terminal, TP7 and ground to the GND terminal, TP8. 6) Apply 1.4V to TP12 to set the MAX3654 gain to minimum, 43.5dBΩ. A voltage from 0.175V to 1.4V at TP12 adjusts the gain from 62dBΩ to 43.5dBΩ Input and Output Signal Levels When used in the electrical input configuration shown in Figure 2, the MAX3654 is intended to operate with AC input signal current from 175μAP-P to 1.6mAP-P. The corresponding electrical input is -37dBm (0 < VAGC < 0.175V) to -18dBm (VAGC = 1.4V), on 50Ω. The MAX3654 EV Kit can also be configured to provide 75Ω input impedance by replacing R12 and R13 with 25Ω resistors. When used in the optical input configuration shown in Figure 2, JU2 may be connected to R3 to configure the MAX3654 for AGC operation based on the average optical power level. In this case, the MAX3654 transimpedance is controlled by the average optical power level, as measured by the voltage across R21. The values of R1, R21 and R22 shown in Figure 1 will provide an output level of 15dBmV/ch (+1dB) for optical input signals ranging from -6dBm to +2dBm, (OMI = 3.5%, N = 129) using a typical triplexer photodiode. The total output signal level in this case is 15dBmV/ch + 10 log(129 channels) = 36dBmV, which is the maximum operating level at which the specified linearity will be achieved. Operating at higher outputs may reduce MAX3654 performance. Operating conditions (OMI, number of channels, responsivity, etc) change the VAGC setting required for a given output voltage. EV Kit AGC circuit gain can be increased by adding a voltage-divider, R22, to the op amp. To reduce gain the values of R1 and R21 should both be increased. Remember to keep the total output at 36dBmV or less to maintain the desired MAX3654 performance. Photodiode Lead Configuration Photodiode lead parasitic impedances can significantly effect performance of the MAX3654. It is especially important that the anode and cathode connections are electrically symmetric. Refer to Figure 1 in the MAX3654 data sheet. Note that the EV Kit layout is designed to minimize capacitance to ground in the input signal path. 2 _________________________________________________________________________________________ MAX3654 Evaluation Kit COMPONENT NAME FUNCTION JU1 MUTE NA JU2 VAGC MUTE. TTL high enables output. Low mutes output. Gain Control. Set JU2 to R4 for manual gain control. Set JU2 to R3 to allow feedforward AGC operation. The electrical circuit board is always set for manual gain control. JU6 JU3 Hysteresis ELECTRICAL OPTICAL JU5 R2 L2 2 C1 0.001μF R21 1kΩ L6 10μH L5 BEAD TP13 VPD TP1 VCC TP5 R4 100kΩ 1μF R22 Open VPD OUT+ MAX3654 IN- OUT- U1 EP* VCC 0.1μF VCC 5 6 7 8 VCC 12 0.001μF C4 11 10 VCC C5 0.001μF 9 EP J2 U8 CX2038 C9 0.1μF R9 JU3 20kΩ HYST TP3 TP4 R5 100kΩ JU1 VCC MUTE C11 R6 R7 1μF 1.62kΩ 2.43kΩ TP2 GND TEST1 GND IN+ C29 C8 0.1μF VCC MAX4240 - U2 C13 33μF 13 VCC C12 0.1μF + VCC C14 33μF C6 VCC JU2 VAGC C10 1μF VCC 4 R3 100kΩ BLM15HD182SN1 TP6 GAIN 3 C2 0.001μF U5 14 GND 1 15 HYST R1 1kΩ 16 C7 0.1μF VCC TEST2 L1 BEAD BLM15HD182SN1 MUTE C3 0.1μF GND 10μH 10Ω VAGC VPD Hysteresis. Leave open for (minimum) ±0.13dB hysteresis between gain switch points. Connect 20kΩ to ground for ±0.3dB and short to GND for (maximum) ±0.65dB hysteresis. R8 6.04kΩ *EP - Exposed Pad, Solder to GND Figure 1. MAX3654 Optical EV Kit Schematic _______________________________________________________ 3 Evaluates: MAX3654 _____________________________________Adjustments and Control Descriptions C19 12Ω 0.001μF 3 4 TP12 GAIN TP8 TP11 GND TEST1 GND TEST2 EP* 5 6 7 8 R16 100kΩ VCC C22 0.001μF 9 VCC EP J4 U7 CX2038 C24 0.1μF R15 + C25 1μF MAX4240 - U4 VCC TP7 VCC 0.1μF 10 OUT- U3 VCC C17 C27 VCC 0.1μF MAX3654 IN- VCC 0.001μF C21 11 OUT+ IN+ VCC 12 VCC VCC 2 C23 0.1μF 13 GND R13 14 HYST CX2039 0.001μF 15 MUTE U6 12Ω 16 1 C20 R12 J3 C16 0.1μF GND VCC VAGC Evaluates: MAX3654 MAX3654 Evaluation Kit JU6 HYST TP9 R17 100kΩ C28 33μF C26 1μF TP10 20kΩ JU5 VCC R18 MUTE R19 R20 1.62kΩ 2.43kΩ 6.04kΩ *EP - Exposed Pad, Solder to GND Figure 2. MAX3654 Electrical EV Kit Schematic 4 ________________________________________________________________________________________ MAX3654 Evaluation Kit Evaluates: MAX3654 Figure 3. MAX3654 EV Kit PC Component Placement Guide— Component Side Figure 5. MAX3654 EV Kit PC Board Layout—Ground Plane Figure 4. MAX3654 EV Kit PC Board Layout—Component Side Figure 6. MAX3654 EV Kit PC Board Layout—Power Plane Figure 7. MAX3654 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600___________________5 © 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products