19-3193; Rev 0, 2/04 MAX3738 Evaluation Kit ________________________ Features The MAX3738 evaluation kit (EV kit) is an assembled demonstration board that provides complete optical and electrical evaluation of the MAX3738. Fully Assembled and Tested The EV kit is composed of two independent sections, one optical and one electrical, on the PC board. The output of the electrical evaluation section is interfaced to an SMP connector that can be connected to a 50Ω terminated oscilloscope. The output of the optical evaluation section is configured for attachment to a laser/monitor diode. AC-Coupling Provided On-Board Single +3.3V Power Supply Operation Allows Optical and Electrical Evaluation _______________Ordering Information PART TEMP RANGE MAX3738EVKIT -40°C to +85°C IC-PACKAGE 24 Thin QFN ________________________________________Electrical Evaluation Component List DESIGNATION C1, C2, C17, C19, C39, C41 C3, C6, C14, C16 C7, C9, C11, C32 QTY C10 1 C4, C5, C12 3 C18, C36 1 J7 1 J1, J2 2 6 4 4 JU1, JU8, JU11, JU14, JU15, JU17-JU19 JU12, JU13 JU3-JU5 J8, J13, J14, TP2-TP4, TP6, TP7, TP9, TP10, TP12, TP14-TP17 DESCRIPTION 0.1µF ±10% ceramic capacitors (0402) 0.01µF ±10% ceramic capacitors (0402) 0.01µF ±10% ceramic capacitors (0201) 0.5pF ±10% ceramic capacitor (0201) 470pF ±10% ceramic capacitors (0402) 10µF ±10% tantalum capacitor, case B SMP connector, Tensolite P698-2CC SMA connectors, round, Johnson 142-0701-801 8 2-pin headers, 0.1in centers 2 3 4-pin headers, 0.1in centers 3-pin headers, 0.1in centers 15 Test Points DESIGNATION QTY DESCRIPTION L2, L5 2 Q3 1 Q1 1 Q2 1 D1 R23-R25, R28R34, R41, R42, R49 R11 R12, R13, R14 R50 R18 R10 R58 R61 R8, R9 R1-R3, R5, R6 1 1.0µH inductor (1008LS) Coilcraft 1008CS-122XKBC MOSFET (SOT23) Fairchild FDN306P NPN transistor (SOT23) Zetex FMMT491A PNP transistor (SOT23) Zetex FMMT591A LED, red T1 package — Not installed 1 3 1 1 1 1 1 1 5 4.99Ω ±1% resistor (0402) 30.1Ω ±1% resistors (0402) 75Ω ±1% resistor (0402) 392Ω ±1% resistor (0402) 511Ω ±1% resistor (0402) 332Ω ±1% resistor (0402) 3.32kΩ ±1% resistor (0402) 4.7kΩ ±1% resistor (0402) 100Ω ±1% resistor (0402) 20kΩ Variable Resistor (3296W) 50kΩ Variable Resistor (3296W) R26 1 R4, R7, R27 3 __________________________________________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: MAX3738 _______________ General Description MAX3738 Evaluation Kit Evaluates: MAX3738 _______________________________Electrical Evaluation Component List (cont.) DESIGNATION U2 QTY 1 U3 1 None None None 7 1 1 DESCRIPTION MAX495ESA (8 SO) MAX3738ETJ (24 Thin QFN) Shunts MAX3738 EV board MAX3738 data Sheet _________________________________________Optical Evaluation Component List DESIGNATION C23, C25, C28, C30, C31, C33, C40 QTY 7 C26, C29 2 C24* 1 C27, C34, C35 3 C20, C22, C37, C38 4 C21 1 D3 D4 — 1 J4, J5 2 JU16, JU20, JU30 3 L4 1 L3 1 Q4 1 Q6 1 DESCRIPTION 0.01µF ±10% ceramic capacitors (0402) 0.01µF ±10% ceramic capacitors (0603) 8.2pF ±10% ceramic capacitor (0402) 470pF ±10% ceramic capacitors (0402) 0.1µF ±10% ceramic capacitors (0402) 10µF ±10% tantalum capacitor, case B Open, user-supplied laser LED, red T1 package SMA connectors, round, Johnson 142-0701-801 2-pin headers, 0.1in centers Ferrite bead (0603) Murata BLM18GA601SN1 1.0µH inductor (1008CS) Coilcraft 1008CS-122XKBC MOSFET (SOT23) Fairchild FDN306P NPN transistor (SOT23) Zetex FMMT491A DESIGNATION R35-R38, R40, R43-R47 R39*, R48 R54 R56 R59 R60 QTY R62 1 R65 DESCRIPTION — Not installed 1 1 1 1 1 1 49.9Ω ±1% resistor (0402) 10Ω ±1% resistor (0402) 15Ω ±1% resistor (0402) 511Ω ±1% resistor (0402) 4.7kΩ ±1% resistor (0402) 3.32kΩ ±5% resistor (0402) 332Ω ±5% resistor (0402) R63, R64, R68 3 100Ω ±5% resistor (0402) R51-R53 — R55 1 Not installed 20kΩ variable resistors Bourns 3296W 50kΩ variable resistors R57 1 U4 J3, J6, TP1, TP5, TP8, TP11, TP13, TP19, TP20, TP25-TPT27 None None None 1 MAX3738EGJ (32 QFN) 12 Test points 1 1 1 Shunt MAX3738 EV board MAX3738 data sheet Bourns 3296W *These components are part of the compensation network, which can reduce overshoot and ringing. Ringing due to parasitic series inductance of the laser may be eliminated with R39 and C24. Starting values for most coaxial lasers is R39 = 49.9Ω in series with C24 = 8.2pF. These values should be experimentally adjusted until the output waveform is optimised. ______________ Component Suppliers SUPPLIER PHONE FAX AVX 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 Note: Please indicate that you are using the MAX3738 when contacting these component suppliers. 2 _________________________________________________________________________________________ MAX3738 Evaluation Kit __________________________Quick Start 11) Attach a high-speed oscilloscope with a 50Ω input to the SMP connector J7 (OUT+). Electrical Evaluation 1) Place shunts on JU1, JU3, JU4, JU5, JU12, JU13, and JU19 (Refer to Table 1 for details). 2) If the EV kit is to be used without the optional shutdown transistor (Q3), place a shunt on JU11. 3) Remove the shunt from JU15 to use the filter inductor. 4) Connect TX_DISABLE to GND with JU1 to enable the outputs. 5) Note: J7 has a DC voltage of approximately VCC/2 and can have voltage swings greater than 1V. An attenuator might be needed to make the signal compatible with the oscilloscope. 12) Connect a +3.3V supply between VCC and GND Adjust the power supply until the voltage between TP12 and ground is +3.3V. 13) Adjust R25 (RAPCSET) until the desired laser bias current is achieved. I BIAS = 14) The MD and BIAS currents can be monitored at TP2 (VPC_MON) and TP3 (VBC_MON) using the equation below: I MD = Standard electrical tests have bias and modulation current separated. Check that R11 (between TP6 and TP7) is installed. I BIAS = Note: When performing the following resistance checks, manually set the ohmmeter to a high range to avoid forward biasing the on-chip ESD protection diodes. 6) Adjust R27, the RMODSET potentiometer, for 25kΩ resistance between TP10 and ground. 7) Adjust R26, the RAPCSET potentiometer, for 25kΩ resistance between TP9 and ground. 8) 9) R PC_MON 80 × VBC_MON R BC_MON I MOD = Signal Amplitude (VP -P ) 15Ω VREF I MDMAX Adjust R7, the RBC_MON potentiometer, to set the maximum bias current (IBIASMAX, see below). RBC_MON can be measured from TP2 to ground. Connect the RBC_MON using JU4. R BC_MON VPC_MON 15) Adjust R27 until the desired laser modulation current is achieved. Measure IMOD with the oscilloscope at J7 by; Adjust R4, the RPC_MON potentiometer, to set the maximum monitor diode current (IMDMAX, see below). RPC_MON can be measured from TP1 to ground. Connect the RPC_MON using JU3. R PC_MON = VTP7 - VTP6 4.9Ω 80 × VREF = I BIASMAX 10) Apply a 2.7Gbps differential input signal (200mVP-P to 2400mVP-P) between SMA connectors J1 and J2 (IN+ and IN-). Optical Evaluation For optical evaluation of the MAX3738, configure the evaluation kit as follows: 1) Remove shunt JU16 to use the filter inductor. 2) If the EV kit is to be used without the optional shutdown transistor (Q4), place a shunt on JU20. 3) To enable the outputs, connect TX_DISABLE to GND by placing a shunt on JU30. 4) The EV kit is designed to allow connection of a variety of possible laser/monitor diode pin configurations. Connect a TO-header style laser with monitor diode (Figure 1) as follows: ________________________________________________________ 3 Evaluates: MAX3738 In the electrical configuration, an automatic power control (APC) test circuit is included to emulate a semiconductor laser with a monitor photodiode. Monitor diode current is provided by transistor Q2, which is controlled by an operational amplifier (U2). The APC test circuit consisting of U2 and Q2 applies the simulated monitor diode current (the DC laser current divided by a factor of 80) to the MD pin of the MAX3738. Evaluates: MAX3738 MAX3738 Evaluation Kit • Keeping its leads as short as possible, connect the laser diode to two of the three pads in the cutout portion on the top (component) side of the PC board. Solder the laser diode cathode to the center pad, and solder the anode to either of the other two pads (they are both connected to VCC through the shutdown transistor (Q4)). • Connect the monitor photodiode to two of the five pads on the bottom (solder) side of the PC board, directly below the laser diode pads. Connect the anode and cathode of the photodiode as shown in figure 1. Note: When performing the following resistance checks, manually set the ohmmeter to a high range to avoid forward biasing the on-chip ESD protection diodes. 5) 6) Adjust R57, the RMODSET potentiometer, for maximum resistance (≈50kΩ) between TP19 and ground. This sets the modulation current to a low value (<10mA). (Refer to the Design Procedure section of the MAX3738 data sheet.) Adjust R55, the RAPCSET potentiometer, for maximum resistance (≈50kΩ) between TP20 and ground. This sets the photodiode current to a low value (<18µA). (Refer to the Design Procedure section of the MAX3738 data sheet.) WARNING: Consult your laser data sheet to ensure that 18µA of photodiode current and 10mA of modulation current does not correspond to excessive laser power. 7) Install R64, the RPC_MON resistor, to set the maximum monitor diode current (IMDMAX, see below). R PC_MON = 8) VREF I MDMAX Install R63, the RBC_MON resistor, to set the maximum bias current (IBIASMAX, see below). R BC_MON = 9) 80 × VREF I BIASMAX Apply a 2.7Gbps differential input signal (200mVP-P to 2400mVP-P) between SMA connectors J5 and J4 (IN+ and IN-). 10) Attach the laser diode fiber connector to an optical/electrical converter. 11) Connect a +3.3V supply between J3 (VCC) and J6 (GND). Adjust the power supply until the voltage between TP15 and ground is +3.3V. 12) Adjust R55 (RAPCSET) until the desired average optical power is achieved. 13) The MD, MOD and BIAS currents can be monitored at TP27 (VPC_MON) and TP26 (VBC_MON) using the equations below: I MD = I BIAS = VPC_MON R PC_MON 80 × VBC_MON R BC_MON Note: If the voltage at TP26 or TP27 exceeds 1.38V, the TX_FAULT signal will be asserted and latched. 14) Adjust R57 (RMODSET) until the desired optical amplitude is achieved. Optical amplitude can be observed on an oscilloscope connected to an optical/electrical converter. Laser overshoot and ringing can be improved by appropriate selection of R39 and C24, as described in the Design Procedure section of the MAX3738 data sheet. 4 _________________________________________________________________________________________ MAX3738 Evaluation Kit Table 1. Adjustment and Control Descriptions (see Quick Start first) COMPONENT NAME FUNCTION ELECTRICAL D4 D1 Fault Indicator LED is illuminated when a fault condition has occurred (Refer to the Detailed Description section of the MAX3735 data sheet). JU16 JU15 — Placing a shunt on JU15 or JU16 removes the inductor from the filter networks by shorting the inductor lead together. Remove shunts for normal operation. — JU13 — Placing a shunt on JU13 connects the MODSET pin of the MAX3738 to the RMODSET potentiometer. Select a fixed resistor value when testing over temperature. JU30 JU1 TX_DISABLE Enables/disables the output currents. Active low (shunt across JU1 or JU30 to enable output currents). — JU12 — Placing a shunt on JU12connects the APCSET pin of the MAX3738 to the RAPCSET potentiometer. Select a fixed resistor value when testing over temperature. JU20 JU11 — Installing a jumper on JU11 or JU20 disables the optional shutdown transistors. R40, R57 R27, R29, R30 RMODSET Adjusts the laser modulation current R45, R55 R23, R24, R26 RAPCSET Adjusts the monitor diode current level to be maintained by the APC loop R51, R38 R31, JU14 RMODBCOMP R52, R37 R32, JU18 RTH_TEMP R53, R36 R33, JU17 RMODTCOMP Evaluates: MAX3738 OPTICAL Sets the K factor compensation of the modulation current. Leave open to make modulation current independent of bias current. Sets the threshold temperature above which modulation current increases with temperature. Sets the temperature coefficient of the modulation current. Leave open to make modulation current independent of temperature. ________________________________________________________ 5 MAX3738 Evaluation Kit CONFIGURATION 1 CONFIGURATION 2 Evaluates: MAX3738 TOP OF PC BOARD TOP OF PC BOARD R19 VCC R19 VCC VCC VCC T0-46 CAN LASER/PHOTODIODE PAIR LD PD SOLDER BRIDGES VCC T0-46 CAN LASER/PHOTODIODE PAIR LD PD VCC SOLDER BRIDGES VCC VCC TO MD TO MD BOTTOM OF PC BOARD BOTTOM OF PC BOARD CONFIGURATION 3 CONFIGURATION 4 TOP OF PC BOARD TOP OF PC BOARD R19 VCC R19 VCC LD VCC VCC T0-46 CAN LASER/PHOTODIODE PAIR LD PD SOLDER BRIDGES VCC T0-46 CAN LASER/PHOTODIODE PAIR PD VCC SOLDER BRIDGES VCC VCC TO MD BOTTOM OF PC BOARD TO MD BOTTOM OF PC BOARD Figure 1. Attachment of Laser Diode/Monitor Diode to the MAX3738 EV Kit 6 _________________________________________________________________________________________ ________________________________________________________ C39 0. 1 µ F GND C19 0. 1 µ F J8 V CC_OUT J14 J13 J2 IN- J1 IN+ C17 0.1 µ F C2 0. 1µ F C1 0. 1µ F R49 OP E N C41 L5 0.1 µ F 1. 0 µ H C36 10 µ F C18 10 µ F R41 OP E N R25 OP E N T P 17 V CC1 R P C _MON V CC1 R42 OP E N R1 100 Ω R28 OP E N 2V CC JU19 V CC1 T P 16 T P 14 R4 50k Ω JU3 C6 0.01 µ F C3 V CC1 0.01 µ F C4 470pF R B C_MON R5 100Ω T P2 JU1 V CC1 R33 OP E N JU17 R32 OP E N JU18 R31 OP E N JU14 JU4 C5 470pF T P3 22 MAX3738 U3 21 9 10 R6 100 Ω C8 20pF R8 4. 7k Ω V CC1 20 R58 332 Ω R29 OP EN S HUT DOW N 8 T X _DIS A B LE V CC I N- I N+ R7 50k Ω 6 5 4 3 23 T P 10 JU13 R27 50k Ω R61 3.3k Ω 7 M ODT COM P 2 V CC 1 24 R2 100Ω T H_T E M P PC_M ON L2 1. 0µ H M ODB COM P BC_M ON V CC M ODS E T SHUT DOWN R MODS E T A P CS E T GND T P 15 T P 12 V CC1 R3 100Ω 19 C16 0.01µ F R30 OP E N R A P CS E T 11 R9 4.7k Ω T P4 12 A P CF ILT 2 T X _F A ULT R34 OP E N A P CF ILT 1 GND BIAS V CC OUT - OUT + V CC MD R10 511 Ω Q1 F M M T 491A F A ULT D1 LE D V CC1 C10 0. 5pF C7 0. 01µ F R23 OP E N R12 30.1 Ω R13 30.1 Ω 2V CC C32 0.01 µ F Q2 F M M T 591A S HUT DOW N JU8 C9 0. 01µ F JU11 Q3 F DN306P R14 30. 1 Ω C11 0.01 µ F TP9 V CC1 R24 OP E N V CC1 13 14 15 16 17 18 C12 470pF JU12 R26 20k Ω V CC1 6 C14 0. 01 µ F R50 75 Ω MAX495 R18 392Ω 4 7 U2 3 2 V CC1 J7 OUT + Evaluates: MAX3738 JU15 T P7 T P6 R11 4. 99Ω MAX3738 Evaluation Kit Figure 2. MAX3738 EV Kit Schematic—Electrical Configuration 7 C20 0. 1µ F GND J4 I N- J5 I N+ J6 J3 V CC R46 OP E N C37 0.1 µ F C38 0.1 µ F R43 OP E N C21 10µ F L3 1. 0 µ H R64 100 Ω R P C _MON V CC2 R47 OP E N R68 100 Ω R44 OP E N V CC2 T P 11 T P 27 C22 0.1 µ F T P 5 TP1 R36 OP E N R37 OP E N R38 OP E N C33 0. 01 µ F C40 0. 01 µ F R63 100 Ω R B C _MON C35 470pF JU30 T P 13 V CC2 T P 26 C34 470pF V CC2 V CC2 24 7 T X _DIS A B LE V CC I N- I N+ V CC M ODT COM P R53 OP E N R52 OP E N R51 OP E N 23 M ODB COM P Q6 F M M T 491 A F A ULT 22 T P 19 D4 LE D 9 R60 4. 7k Ω 10 20 R40 OP E N MAX3738 U1 21 R62 3. 32k Ω R57 50k Ω R MOD S E T R59 511 Ω VCC2 8 BC_M ON R35 OP E N A P CS E T GND JU16 11 R65 332Ω 19 C23 0. 01µ F A P CF I LT 2 12 T P 25 T X _F A UL T T H_T E M P PC_M ON M ODS E T S HUT DOWN S HUT DOW N R45 OP E N T P 20 R56 15Ω B IA S V CC C30 0.01 µ F C24 8.2pF OUT - V CC2 C28 0. 01 µ F C27 470pF R48 49. 9Ω R39 49. 9Ω V CC2 T P8 OUT + V CC MD R55 20k Ω RA P CSE T A P CF ILT 1 GND B LM18HG601S N1 L4 M URA T A R54 10 Ω (SE E F IGURE 1) (S E E F I GURE 1) 6 4 LA S E R S B3 1 2 3 D3 P HOT ODIODE 5 S B1 S B2 C25 0.01 µ F SB 4 SB 5 SB 6 JU20 C31 0.01 µ F C26 0. 01 µ F S HUT DOW N Q4 F DN306P C29 0.01 µ F V CC2 Evaluates: MAX3738 MAX3738 Evaluation Kit Figure 3. MAX3738 EV Kit Schematic—Optical Configuration 8 ________________________________________________________________________________________ MAX3738 Evaluation Kit Evaluates: MAX3738 Figure 4. MAX3738 EV Kit PC Component Placement Guide-Component Side Figure 5: MAX3738 EV Kit PC Component Placement Guide-Solder Side ________________________________________________________ 9 Evaluates: MAX3738 MAX3738 Evaluation Kit Figure 6. MAX3738 EV Kit PC Board Layout Component Side Figure 7: MAX3738 EV Kit PC Board Layout – Ground Plane 10 ________________________________________________________________________________________ MAX3738 Evaluation Kit Evaluates: MAX3738 Figure 8: MAX3738 EV Kit PC Board Layout – Power Plane Figure 9: MAX3738 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 o change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________ 11 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products