19-2567; Rev 1, 09/03 MAX3735A Evaluation Kit ________________________ Features The MAX3735A evaluation kit (EV kit) is an assembled demonstration board that provides complete optical and electrical evaluation of the MAX3735A. 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 IC-PACKAGE MAX3735AEVKIT -40°C to +85°C 24 QFN* *Exposed pad. ________________________________________Electrical Evaluation Component List DESIGNATION C1, C10, C11, C13, C14 C2, C12, C19, C20 QTY C3 1 C4, C5, C16, C17, C18 5 C7, C8, C9 3 C15 1 C21 1 D1 D2 J1 1 1 1 J2, J3 2 5 — JU1, JU5, JU6, JU7, JU9, JU10, JU13, JU14 JU8, JU15 JU11 JU25 L1, L5 DESCRIPTION 0.01µF ±10% ceramic capacitors (0402) Open 0.5pF ±10% ceramic capacitor (0201) 0.1µF ±10% ceramic capacitors (0402) 470pF ±10% ceramic capacitors (0402) 0.01µF ±10% ceramic capacitor (0201) 10µF ±10% tantalum capacitor, case B Diode, DIO-S1A LED, red T1 package SMP connector SMA connectors, tab contact 8 2-pin headers, 0.1in centers — — — — Open Open Open, 0201 solder bridge Open DESIGNATION Q1 1 Q2 — Q3 1 Q4 1 R1, R34–R40 R2 R3, R4, R5 R6 R7 R8 R9 R10 R11 R13 R14–R17 R41 U1 U2 VCC, GND, TP1– TP11, TP22 — 1 3 1 1 1 1 1 1 1 4 1 1 1 DESCRIPTION MOSFET (SOT23) Fairchild FDN306P Open NPN transistor (SOT23) Zetex FMMT491A PNP transistor (SOT23) Zetex FMMT591A Open 5.1Ω ±1% resistor (0402) 30Ω ±1% resistors (0402) 75Ω ±1% resistor (0402) 200Ω ±1% resistor (0402) 392Ω ±1% resistor (0402) 511Ω ±1% resistor (0402) 1.5kΩ ±1% resistor (0402) 4.3kΩ ±1% resistor (0402) 0Ω resistor (0603) 50kΩ variable resistors 0Ω resistor (0201) MAX3735AETG (24 QFN) MAX495ESA (8 SO) 14 Test points 8 1 1 Shunts MAX3735 EV board MAX3735A data sheet None None None QTY __________________________________________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: MAX3735A _______________ General Description Evaluates: MAX3735A MAX3735A Evaluation Kit _________________________________________Optical Evaluation Component List DESIGNATION C22, C23, C38, C39 QTY C24 1 C25, C26, C27 3 C28–C35 8 C36, C37 2 C40 — C41 1 D3 — D4, D5, D6 J4, J5 J6 JU16–JU20 JU21, JU22 3 2 — 5 2 L3 1 L4 1 4 DESCRIPTION 0.1µF ±10% ceramic capacitors (0402) 8.2pF ±10% ceramic capacitor (0402)* 470pF ±10% ceramic capacitors (0402) 0.01µF ±10% ceramic capacitors (0402) 0.01µF ±10% ceramic capacitors (0603) Open 10µF ±10% tantalum capacitor, case B Open, user-supplied laser diode LED, red T1 Package SMA connectors, tab contact Open** 2-pin headers, 0.1in centers 3-pin headers, 0.1in centers 600Ω ferrite bead (0603) Murata BLM18HG601SN1 1µH inductor (1008CS) Coilcraft 1008CS-102XKBC DESIGNATION QTY Q5 1 Q6 1 R18 R19 R20 — 1 1 R21 1 R22 R23 R24 R25 1 1 1 1 R26, R27 2 R28, R29 2 R30–R33 U3 U4 VCC, GND, TP12–TP21 None None None 4 — 1 DESCRIPTION MOSFET (SOT23) Fairchild FDN306P NPN transistor (SOT23) Zetex FMMT491A Open (0402) 11Ω ±1% resistor (0402) 15Ω ±1% resistor (0402) 49.9Ω ±1% resistor (0402)* 200Ω ±1% resistor (0402) 511Ω ±1% resistor (0402) 1.5kΩ ±1% resistor (0402) 4.3kΩ ±1% resistor (0402) 4.7kΩ ±1% resistors (0402) 330Ω ±1% resistors (0603) 50kΩ variable resistors Open** MAX3735AETG (24 QFN) 12 Test points 7 1 1 Shunts MAX3735 EV board MAX3735A data sheet *These components are part of the compensation network, which can reduce overshoot and ringing. Parasitic series inductance introduces a zero into the laser’s frequency response. R21 and C24 add a pole to cancel this zero. Starting values for most coaxial lasers is R21 = 49.9Ω in series with C24 = 8.2pF. These values should be experimentally adjusted until the output waveform is optimized. **These components are not supplied on the EV kit but can be populated if the customer wants to use the MAX3735A laser driver with the DS1858 dual temperature controlled digital resistor with current monitors. See schematics on page 8 for details. ______________ 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 MAX3735A when contacting these component suppliers. 2 _________________________________________________________________________________________ MAX3735A Evaluation Kit __________________________Quick Start Electrical Evaluation 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 Q4, which is controlled by an operational amplifier (U2). The APC test circuit consisting of U2 and Q4 applies the simulated monitor diode current (the laser bias current divided by a factor of 77) to the MD pin of the MAX3735A. To ensure proper operation in the electrical configuration, set up the evaluation board as follows: 1) Place shunts on JU5, JU6, JU7, JU10 and JU14 (Refer to table 1 for details). 2) If the EV kit is to be used without the optional shutdown transistor (Q1), place a shunt on JU13. 3) Remove the shunt from JU1 to use the filter inductor. 4) To enable the outputs, connect TX_DISABLE to GND by placing a shunt on JU9. 11) Connect a +3.3V supply between TP2 (VCC) and TP1 (GND) Adjust the power supply until the voltage between TP7 and ground is +3.3V. 12) Adjust R16 (RAPCSET) until the desired laser bias current is achieved. I BIAS = VTP3 - VTP5 5.11Ω 13) The MD and BIAS currents can be monitored at TP10 (VPC_MON) and TP11 (VBC_MON) using the equation below: I MD = 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. I BIAS = VPC_MON R PC_MON 76 × VBC_MON R BC_MON 5) Adjust R15, the RMODSET potentiometer, for 25kΩ resistance between TP6 and ground. Note: If the voltage at TP10 or TP 11 exceeds 1.38V, the TX_FAULT signal will be asserted and latched. 6) Adjust R16, the RAPCSET potentiometer, for 25kΩ resistance between TP4 and ground. 14) Adjust R15 until the desired laser modulation current is achieved. 7) Adjust R17, the RPC_MON potentiometer, to set the maximum monitor diode current (IMDMAX, see below). RPC_MON can be measured from TP10 to ground. R PC_MON = 8) Adjust R14, the RBC_MON potentiometer, to set the maximum bias current (IBIASMAX, see below). RBC_MON can be measured from TP11 to ground. R BC_MON = 9) 1.38V I MDMAX 76 × 1.38V I BIASMAX Apply a differential input signal (200mVP-P to 2400mVP-P) between SMA connectors J2 and J3 (IN+ and IN-). 10) Attach a high-speed oscilloscope with a 50Ω input to the SMP connector J1 (OUT+). I MOD = Signal Amplitude (V) 15Ω Optical Evaluation For optical evaluation of the MAX3735A, configure the evaluation kit as follows: 1) Place a shunt on JU18 to connect the FAULT indicator and remove shunt JU20 to use the filter inductor. 2) Place a shunt across pin 2 (MODSET) and pin 1 (RMODSET) of JU21. This connects the MODSET pin to the RMODSET potentiometer (R31). 3) Place a shunt across pin 2 (APCSET) and pin 3 (RAPCSET) of JU22. This connects the APCSET pin to the RAPCSET potentiometer (R30). 4) If the EV kit is to be used without the optional shutdown transistor (Q5), place a shunt on JU17. ________________________________________________________ 3 Evaluates: MAX3735A Note: J1 has a DC voltage of approximately VCC/2 and can have voltage swings greater than 1V. Care should be taken that the large swing and DC voltage do not damage the test equipment. An attenuator might be needed to make the signal compatible with the oscilloscope’s input requirements. Evaluates: MAX3735A MAX3735A Evaluation Kit 5) To enable the outputs, connect TX_DISABLE to GND by placing a shunt on JU16. 6) 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: • • 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 (Q5)). 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. 7) 8) Adjust R31, the RMODSET potentiometer, for maximum resistance (≈50kΩ) between TP17 and ground. This sets the modulation current to a low value (<10mA). (Refer to the Design Procedure section of the MAX3735A data sheet.) Adjust R30, the RAPCSET potentiometer, for maximum resistance (≈50kΩ) between TP19 and ground. This sets the photodiode current to a low value (<18uA). (Refer to the Design Procedure section of the MAX3735A 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. 9) Adjust R33, the RPC_MON potentiometer, to set the maximum monitor diode current (IMDMAX, see below). R PC_MON = 1.38V I MDMAX 10) Adjust R32, the RBC_MON potentiometer, to set the maximum bias current (IBIASMAX, see below). R BC_MON = 76 × 1.38V I BIASMAX 11) Apply a differential input signal (200mVP-P to 2400mVP-P) between SMA connectors J5 and J4 (IN+ and IN-). 12) Attach the laser diode fiber connector to an optical/electrical converter. 13) Connect a +3.3V supply between TP12 (VCC) and TP13 (GND). Adjust the power supply until the voltage between TP15 and ground is +3.3V. 14) Adjust R30 (RAPCSET) until the desired average optical power is achieved. 15) The MD and BIAS currents can be monitored at TP16 (VPC_MON) and TP18 (VBC_MON) using the equations below: I MD = I BIAS = VPC_MON R PC_MON 76 × VBC_MON R BC_MON Note: If the voltage at TP16 or TP18 exceeds 1.38V, the TX_FAULT signal will be asserted and latched. 16) Adjust R31 (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 R21 and C24, as described in the Design Procedure section of the MAX3735A data sheet. 4 _________________________________________________________________________________________ MAX3735A Evaluation Kit ______________ Adjustment and Control Descriptions (see Quick Start first) OPTICAL ELECTRICAL D6 D2 JU22 — NAME Evaluates: MAX3735A COMPONENT FUNCTION Fault Indicator LED is illuminated when a fault condition has occurred (Refer to the Detailed Description section of the MAX3735A data sheet). — Connects the APCSET pin to either the potentiometer or the Dallas digital resistor. Shunt pin 2 to pin 3 when using the potentiometer. Shunt pin 2 to pin 1 when using the Dallas DS1858 controller IC. JU21 — — Connects the MODSET pin to either the potentiometer or the Dallas digital resistor. Place a shunt on pin 2 to pin 1 when using the potentiometer. Place a shunt on pin 2 to pin 3 when using the Dallas DS1858 controller IC. JU19 — WP Can be used to enable and disable the write protection feature of the DS1858 controller IC. JU20 JU1 — Placing a shunt on JU1 or JU20 removes the inductor from the filter networks by shorting the inductor lead together. Remove shunts for normal operation. JU18 JU5 — Place a shunt on JU18 or JU5 to connect the open collector FAULT output to the LED indicator. The LED is illuminated when FAULT is asserted. — JU6 — Placing a shunt on JU6 connects the MODSET pin of the MAX3735A to the RMODSET potentiometer. — JU7 — Placing a shunt on JU7 connects the emulated monitor diode current to the MD pin of the MAX3735A. JU16 JU9 TX_DISABLE Enables/disables the output currents. Active low (shunt across JU9 or JU16 to enable output currents). — JU10 — Placing a shunt on JU10 connects the APCSET pin of the MAX3735A to the RAPCSET potentiometer. JU17 JU13 — Installing a jumper on JU13 or JU17 disables the optional shutdown transistors. R31 R15 RMODSET Adjusts the laser modulation current R30 R16 RAPCSET Adjusts the monitor diode current level to be maintained by the APC loop Fault TTL high level indicates a fault condition. Installing and then removing JU16 for the optical section or JU9 for the electrical section will clear the fault condition (Refer to the Detailed Description section of the MAX3735A data sheet). TP14 TP8 ________________________________________________________ 5 Evaluates: MAX3735A MAX3735A Evaluation Kit CONFIGURATION 1 CONFIGURATION 2 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 MAX3735A EV Kit 6 _________________________________________________________________________________________ TP1 GND C18 0.1µF J3 IN- R17 50kΩ RPC_MON J2 IN+ C21 10µF TP10 L2 1µH C8 470pF C20 OPEN TP11 R14 R 50kΩ BC_MON C5 0.1µF C4 0.1µF TP9 C16 0.1µF Q2 OPEN JU15 OPEN JU14 C7 470pF Q3 FMMT491A 24 R11 4.3kΩ 7 VCC18 R9 511Ω D2 LED 6 BC_MON 23 JU9 JU10 5 PC_MON 4 V CC 3 IN- 2 IN+ 1 V CC VCC1 C19 OPEN VCC1 FAULT C10 0.01µF L1 OPEN VCC1 APCSET VCC VCC 22 TP4 U4 21 R7 200Ω JU5 C13 0.01µF 9 10 20 C11 0.01µF TP8 11 TP6 MAX3735A GND SHUTDOWN TP2 APCFILT2 FAULT R13 0Ω SHUTDOWN2 TP7 TX_DISABLE GND APCFILT1 MODSET JU6 19 JU8 OPEN R16 50kΩ 12 R15 50kΩ R10 1.5kΩ BIAS 13 VCC 14 OUT+ 15 OUT+ 16 OUT- 17 VCC 18 RAPCSET MD GND R1 OPEN RMODSET BIAS TP5 R4 30Ω C3 0.5pF MD R41 0Ω L5 OPEN VCC1 R3 30Ω VCC1 MD C1 0.01µF C12 OPEN VCC1 C9 470pF JU7 JU25 R38 OPEN R40 OPEN VCC1 R39 OPEN Q4 FMMT591A R6 75Ω R36 OPEN R5 30Ω C2 OPEN R37 OPEN 4 7 U2 3 2 VCC1 R8 392Ω C17 0.1µF TP22 JU11 MAX495 6 C14 0.01µF OUT+ J1 R35 OPEN JU13 R34 OPEN VCC1 TP3 R2 5.1Ω D1 DIO-S1A BIAS C15 0.01µF SHUTDOWN2 Q1 FDN306P Evaluates: MAX3735A JU1 MAX3735A Evaluation Kit Figure 2. MAX3735A EV Kit Schematic—Electrical Configuration _______________________________________________________ 7 IN- J4 IN+ J5 H0 C25 470pF D4 D3 D2 D1 C41 10µF C4 TP18 H1 VCC2 R32 50kΩ RBC_MON C22 0.1µF C23 0.1µF C40 OPEN C3 U3 OUT1 DS1858 C2 IN2 BGA C1 WP B1 B2 B3 B4 A3 V CC A4 H0 A1 IN1 A2 SCL TP16 C39 0.1µF R33 50kΩ RPC_MON VCC2 GND C29 0.01µF TP13 TP12 L4 1µH TP15 JU19 WP C38 0.1µF VCC2 C26 470pF 24 R23 511Ω R25 4.3kΩ 8 7 VCC2 23 JU16 6 BC_MON D6 LED JU22 R22 200Ω 5 PC_MON 4 V CC 3 IN- 2 IN+ 1 V CC VCC2 Q6 FMMT491A FAULT C30 0.01µF VCC2 R30 50kΩ RAPCSET 22 TP19 U4 21 R26 4.7kΩ JU18 C28 0.01µF 9 11 TP14 R27 4.7kΩ VCC2 10 20 C31 0.01µF H1 MAX3735A 1 GND SHUTDOWN VCC MON2 OUT2 MON1 SDA APCFILT2 FAULT R18 OPEN L1 H1 SHUTDOWN2 JU20 GND MON3 L0 TX_DISABLE GND APCSET VCC APCFILT1 MODSET 19 RMODSET R24 1.5kΩ BIAS 13 VCC 14 OUT+ 15 OUT+ 16 12 TP17 VCC 18 OUT- 17 MD GND R31 50kΩ JU21 1 H0 VCC2 SDA R29 330Ω R20 15Ω TP21 D5 LED C33 0.01µF VCC2 C27 500pF TP20 SCL D4 LED 1 2 3 4 5 6 L3 MURATA R19 11Ω SB4 SB5 BLM18HG601SN1 PHONE JACK J6 C36 0.01µF C34 0.01µF R28 330Ω VCC2 C24 8.2pF R21 49.9Ω C37 0.01µF SB6 6 4 1 2 3 C32 0.01µF VCC2 C35 0.01µF SHUTDOWN2 Q5 FDN306P (SEE FIGURE 1) JU17 (SEE FIGURE 1) LASER D3 PHOTODIODE 5 SB1 SB2 SB3 Evaluates: MAX3735A MAX3735A Evaluation Kit Figure 3. MAX3735A EV Kit Schematic—Optical Configuration 8 ________________________________________________________________________________________ MAX3735A Evaluation Kit Evaluates: MAX3735A Figure 4. MAX3735A EV Kit PC Component Placement Guide—Component Side Figure 5. MAX3735A EV Kit PC Component Placement Guide—Solder Side _______________________________________________________ 9 Evaluates: MAX3735A MAX3735A Evaluation Kit Figure 6. MAX3735A EV Kit PC Board Layout— Component Side Figure 7. MAX3735A EV Kit PC Board Layout—Ground Plane 10 ________________________________________________________________________________________ MAX3735A Evaluation Kit Evaluates: MAX3735A Figure 8. MAX3735A EV Kit PC Board Layout—Power Plane Figure 9. MAX3735A 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___________________11 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products