19-2695; Rev 0; 12/02 MAX3741 Evaluation Kit Features ♦ Fully Assembled and Tested ♦ Single +3.3V Power-Supply Operation ♦ Allows Optical and Electrical Evaluation Component Suppliers PHONE FAX AVX SUPPLIER 803-946-0690 803-626-3123 Coilcraft 847-639-6400 847-639-1469 Murata 814-237-1431 814-238-0490 Zetex 516-543-7100 516-864-7630 Ordering Information PART TEMP RANGE MAX3741EVKIT -40°C to +85°C IC PACKAGE 16 Thin QFN (3mm x 3mm) Note: When contacting these suppliers, please indicate that you are using the MAX3741. Component List DESIGNATION QTY DESCRIPTION 7 0.1µF ±10% ceramic capacitors (0402) C3–C7 5 0.01µF ±10% ceramic capacitors (0402) C8, C11 2 10µF ±10% tantalum capacitors, case B GND, VCC, TP1–TP7, TP9, TP10 11 Test points C1, C2, C9, C10, C12, C13, C14 JU1 1 2-pin header, 0.1in center J1, J2, J3, J6–J9 7 SMA connectors, tab contacts L1 1 1µH inductor (805) L2 1 600Ω ferrite bead (0603) Murata BLM18HD102SN1B L3 1 600Ω ferrite bead (0603)* Murata BLM18HD102SN1B R1 1 10kΩ potentiometer R2, R3, R7, R8 4 Open DESIGNATION QTY R4 1 DESCRIPTION 20kΩ potentiometer R5, R9 2 49.9Ω resistors (0402) R6 1 50kΩ potentiometer R10 1 350Ω resistor (0402) R11 1 120Ω resistor (0402) R12 1 0Ω resistor (0402)* U1 1 MAX3741ETE None 1 Shunt None 1 MAX3741 EV board None 1 MAX3741 data sheet *Not populated, but can be installed for optical evaluation. Quick Start Electrical Evaluation To ensure proper operation in the electrical configuration, set up the evaluation board as follows: 1) To enable the outputs, connect TX_DISABLE to GND by placing a shunt on JU1. Note: When performing the following resistance checks, autoranging DMMs can forward bias the on-chip ESD protection and cause inaccurate measurements. To avoid this problem, manually set the DMM to a high range. ________________________________________________________________ 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: MAX3741 General Description The MAX3741 evaluation kit (EV kit) is an assembled demonstration board that provides complete optical and electrical evaluation of the MAX3741 compact VCSEL driver. The EV kit has an electrical test section and an optical test section. Electrically, the output of the evaluation board is interfaced to an SMA connector, which can be connected to a 50Ω terminated oscilloscope. Optically, the board can be configured to interface with a common-cathode VCSEL. Evaluates: MAX3741 MAX3741 Evaluation Kit 2) Adjust R6, the RBIASSET potentiometer, for 1.7kΩ resistance between TP3 (BIASSET) and ground. 3) Adjust R4, the RPEAKSET potentiometer, for 20kΩ resistance between TP2 (PEAKSET) and ground to disable peaking. 4) Adjust R1, the RMODSET potentiometer, for 10kΩ resistance between TP1 (MODSET) and ground. 5) Apply a differential input signal (250mV P-P to 2200mVP-P) between SMA connectors J1 and J2 (IN+ and IN-). 6) Attach a high-speed oscilloscope with a 50Ω input to SMA connector J3 (OUT). 7) Connect a +3.3V supply between VCC and GND. Adjust the power supply until the voltage between TP10 and ground is +3.3V. 8) Adjust R6 (RBIASSET) until the desired laser bias current is achieved. V IBIAS = TP6 120Ω 9) The BIAS current can be monitored at TP5 (VBIASMON) using the equation below: IBIAS = 9 × VBIASMON 350Ω 10) Adjust R1 (RMODSET) until the desired laser modulation current is achieved. IMOD = Signal Amplitude (V) 50Ω 11) Adjust R14 (RPEAKSET) until the desired amount of peaking is achieved. Optical Evaluation For optical evaluation of the MAX3741, configure the evaluation kit as follows: 1) Remove component R11. 2) Install a 0Ω resistor at R12 and install a 600Ω ferrite bead at L3 (Murata BLM18HD102SN1). 3) To enable the outputs, connect TX_DISABLE to GND by placing a shunt on JU1. 4) Connect a common-cathode VCSEL as shown in Figure 1. Keep the leads short to reduce reflection. Note: When performing the following resistance checks, autoranging DMMs can forward bias the on-chip ESD protection and cause inaccurate mea2 surements. To avoid this problem, manually set the DMM to a high range. 5) Adjust R6, the RBIASSET potentiometer, for 1.7kΩ resistance between TP3 (BIASSET) and ground. 6) Adjust R4, the RPEAKSET potentiometer, for 20kΩ resistance between TP2 (PEAKSET) and ground to disable peaking. 7) Adjust R1, the RMODSET potentiometer, for 10kΩ resistance between TP1 (MODSET) and ground. 8) Apply a differential input signal (250mV P-P to 2200mVP-P) between SMA connectors J1 and J2 (IN+ and IN-). 9) Attach the laser-diode fiber connector to an optical/electrical converter. 10) Connect a +3.3V supply between VCC and GND. Adjust the power supply until the voltage between TP10 and ground is +3.3V. 11) Adjust R6 (RBIASSET) until desired average optical power is achieved. 12) The BIAS current can be monitored at TP5 (VBIASMON) using the equation below: IBIAS = 9 × VBIASMON 350Ω 13) Adjust R1 (RMODSET) until the desired optical amplitude is achieved. Optical amplitude can be observed on an oscilloscope connected to an optical/electrical converter. 14) Adjust R14 (RPEAKSET) until the desired amount of peaking is achieved. Adjustment and Control Descriptions (see Quick Start) COMPONENT JU1 NAME FUNCTION Enables/disables the output TX_DISABLE currents, install a shunt to enable output currents R1 RMODSET Adjusts the laser modulation current R4 RPEAKSET Adjusts the peaking for the falling edge of the VCSEL R6 RBIASSET Adjusts the VCSEL bias current TP5 BIASMON Monitors the bias current _______________________________________________________________________________________ GND J9 CALIN- J7 CALIN+ C8 10µF J1 IN+ C14 0.1µF C13 0.1µF J2 IN- C9 0.1µF C10 0.1µF J8 CALOUT- J6 CALOUT+ C2 0.1µF C12 0.1µF C1 0.1µF 16 C7 0.01µF 15 VCC1 R7 OPEN NC IN- IN+ TP2 R3 OPEN 8 R2 OPEN 7 VCC OUT- OUT+ TP5 9 10 11 12 R10 350Ω R11 120Ω BIASMON R4 20kΩ TP1 6 U1 MAX3741 13 TP6 R1 10kΩ C3 0.01µF 5 TP3 14 R6 50kΩ TX_DISABLE VCC1 4 3 2 1 JU1 TX_DISABLE C11 10µF L2 BLM18HD102SN1B VCC VCC L1 1µH GND VCC1 VCC MODSET TP10 BIASSET PEAKSET BIAS GND C6 0.01µF TP4 C5 0.01µF R5 49.9Ω C4 0.01µF VCC1 R8 OPEN R9 49.9Ω VCC L3 OPEN 1 2 3 4 D1 VCSEL PHOTODIODE TP9 R12 OPEN J3 OUT Evaluates: MAX3741 TP7 MAX3741 Evaluation Kit Figure 1. MAX3741 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX3741 MAX3741 Evaluation Kit 1.0" Figure 2. MAX3741 EV Kit Component Placement Guide— Component Side 4 1.0" Figure 3. MAX3741 EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ MAX3741 Evaluation Kit Evaluates: MAX3741 1.0" 1.0" Figure 4. MAX3741 EV Kit PC Board Layout—Ground Plane Figure 5. MAX3741 EV Kit PC Board Layout—Power Plane _______________________________________________________________________________________ 5 Evaluates: MAX3741 MAX3741 Evaluation Kit 1.0" Figure 6. MAX3741 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 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.