19-2363; Rev 0; 4/02 MAX3850 Evaluation Kit Features ♦ Fully Assembled and Tested The EV kit is composed of two independent electrically isolated sections on the PC board. The output of the electrical evaluation section is interfaced to an SMA connector, which can be connected to a 50Ω terminated oscilloscope. The output of the optical evaluation section is configured for attachment to a laser/monitor diode. ♦ Input Termination Provided On-Board ♦ +3.3V Operation ♦ Independent Electrical Monitoring of Modulation and Bias Currents ♦ Supports Optical and Electrical Evaluation Component Suppliers PHONE FAX AVX SUPPLIER 843-444-2863 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 MAX3850EVKIT TEMP RANGE IC PACKAGE -40°C to +85°C 32 QFN Note: Please indicate that you are using the MAX3850 when ordering from these suppliers. Electrical Component List DESIGNATION QTY DESCRIPTION 0.5pF ±0.1pF, 10V min, ceramic capacitor (0402) 1.0pF ±0.1pF, 10V min, ceramic capacitor (0402) C7 1 C8 1 C24, C25, C28, C32 4 0.01µF ±10%, 10V min, ceramic capacitors (0402) C26, C27, C29, C30, C33 5 0.1µF ±10%, 10V min, ceramic capacitors (0402) C40 1 C41, C45 2 C42 DESIGNATION R4, R17, R44 R5, R22 R6 R23 R28, R32 R34 R37, R43 R38 QTY 3 2 1 1 2 1 2 1 10µF ±20%, 10V min, tantalum capacitor (case B) 0.01µF ±10%, 10V min, ceramic capacitors (0603) R40 1 R41 1 1 0.1µF ±10%, 10V min, ceramic capacitor (0603) R42 1 C43 1 1000pF ±10%, 10V min, ceramic capacitor (0402) 1 1 1 D3 1 J5–J9 JU4, JU5 5 2 11 Test points JU4, JU5 2 R46 R47 R49 TP2, TP3, TP8, TP10–TP13, TP17, TP18, TP21, TP22 U2 U3 200kΩ variable resistor Bourns 3296W-104-ND Digi-Key 15Ω ±1% resistor (0603) 1.5kΩ ±1% resistor (0603) 75Ω ±1% resistor (0402) 1 1 MAX3850EGJ 32 QFN MAX495ESA 8-pin SO L9 1 220nH inductor Coilcraft 1008HS-221TKBC Q2 1 FMMT591A SOT-23 Zetex “91A” marking LED red T1 pkg Digi-Key P363-ND SMA connectors, edge mount 1 × 2-pin headers, 0.1in centers Shunts Digi-Key DESCRIPTION 30.1Ω ±1% resistors (0402) 1.5kΩ ±1% resistors (0402) DO NOT INSTALL (0603) 1kΩ ±1% resistor (0402) 100Ω ±1% resistors (0402) 110Ω ±1% resistor (0603) 392Ω ±1% resistors (0402) 49.9Ω ±1% resistor (0402) 100kΩ variable resistor Bourns 3296W-104-ND Digi-Key 50kΩ variable resistor Bourns 3296W-104-ND Digi-Key ________________________________________________________________ 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: MAX3850 General Description The MAX3850 evaluation kit (EV kit) is an assembled demonstration board that provides optical or electrical evaluation of the MAX3850. MAX3850 Evaluation Kit Evaluates: MAX3850 Optical Component List DESIGNATION QTY C1–C4, C17, C38 C5, C10–C13 C6 C16 6 5 DESCRIPTION DESCRIPTION 0.01µF ±10%, 10V min, ceramic capacitors (0402) R1, R2 2 1.5kΩ ±1% resistors (0402) R3 1 1kΩ ±1% resistor (0402) 0.1µF ±10%, 10V min, ceramic capacitors (0402) R8, R12 2 100Ω ±1% resistors (0402) R14 1 50kΩ variable resistor Bourns 3296W-503-ND Digi-Key R15 1 200kΩ variable resistor Bourns 3296W-503-ND Digi-Key R16 1 100kΩ variable resistor Bourns 3296W-503-ND Digi-Key R18 1 110Ω ±1% resistor (0603) 1 1000pF ±10%, 10V min, ceramic capacitor (0402) 1 0.1µF ±10%, 10V min, ceramic capacitor (0603) C19 1 10µF ±20%, 10V min, tantalum capacitor (Case B) 2 392Ω ±1% resistors (0402) 3 0.01µF ±10%, 10V min, ceramic capacitors (0603) R19, R35 C20, C22, C36 R20 1 11Ω ±1% resistor (0402) 2 49.9Ω ±1% resistors (0402) 1 8.2pF ±10%, 10V min, ceramic capacitor (0402) R21, R36 C35 R27 1 16.2Ω ±1% resistor (0402) D1 1 LED red T1 pkg Digi-Key 363-ND 9 Test points J1–J4 4 SMA connectors, edge mount JU1, JU2 2 1 × 2-pin headers, 0.1in centers TP1, TP4, TP5, TP6, TP14, TP15, TP16, TP19, TP20 1 MAX3850EGJ 32-pin QFN 2 Shunts Digi-Key U1 JU1, JU2 U4 1 User-supplied laser diode None 1 MAX3850 data sheet None 1 MAX3850 EV kit circuit board, rev B None 1 MAX3850 EV kit data sheet L2 L4 1 1 Ferrrite bead Murata BLM18HG601SN1 220nH inductor Coilcraft 1008HS-221TKBC 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 Q2, which is controlled by an operational amplifier (U3). The APC test circuit, consisting of U3 and Q2, applies the simulated monitor diode current (the laser bias current divided by a factor of 100) to the MD pin of the MAX3850. To ensure proper operation of the electrical configuration, set up the evaluation board as follows: 1) If data is to be latched, remove the shunt from JU4 to enable the input clock; otherwise, leave the shunt in place. 2 DESIGNATION QTY 2) Remove the shunt from JU5 to enable the output. Note: When performing the following resistance checks, manually set the ohmmeter to a high resistance range to avoid forward biasing the on-chip ESD-protection diodes. 3) Adjust R41, the MODSET potentiometer, for 10kΩ resistance between test point 3 and ground. 4) Adjust R42, the BIASMAX potentiometer, for 10kΩ resistance between test point 2 and ground. 5) Adjust R40, the APCSET potentiometer, for 10kΩ resistance between test point 8 and ground. 6) Apply a differential input signal (max amplitude ≤ 800mV per side) to J7 and J8 (DATA+ and DATA-). _______________________________________________________________________________________ MAX3850 Evaluation Kit 8) Attach a high-speed oscilloscope with 50Ω inputs to J9. 9) Power up the board with a +3.3V supply 10) Adjust R40 until the desired laser bias current is achieved. V − VTP12 IBIAS = TP13 15Ω Note: The APC function can only subtract from the maximum programmed bias current (set by the BIASMAX resistor, R42). If an APC failure flags before the desired bias current is achieved, increase the maximum bias current by tuning R42 counterclockwise. 11) Adjust R41 until the desired laser modulation current is achieved. IMOD = Signal amplitude (V) 15Ω Note: Because DC voltage at the output is approximately VCC/2, an SMA attenuator might be required. Optical Evaluation For optical evaluation of the MAX3850, configure the evaluation board as follows: 1) If data is to be latched, remove the shunt from JU1 to enable the input clock. Otherwise, leave the shunt in place. 2) Remove the shunt from JU2 to enable the output. 3) The EV kit is designed to allow connection of various 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 cut-out 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, which are both connected to VCC. • 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. Three of these pads (the middle and outside positions) initially are not connected. The other two pads are connected to VCC. Solder the anode and cathode of the monitor photodiode to any two of the three pads that are not connected. Then connect the anode to the MD pin by shorting the corresponding solder jumper (Figure 1). Connect the cathode to V CC by using solder to bridge to an adjacent VCC pad. Adjustment and Control Descriptions (see Quick Start first) COMPONENT NAME FUNCTION OPTICAL ELECTRICAL JU1 JU4 Clock Disable Enables/disables the clock input. Shunt for direct data transition. Remove shunt to enable the clock input. JU2 JU5 Output Disable Enables/disables the output currents. Shunting disables the output currents. Remove shunt for normal operation. None J9 Electrical Output SMA R14 R41 MOD Adjusts the laser modulation current. R15 R42 BIAS Adjusts the laser bias current. In open-loop mode, R42 or R15 adjusts the laser bias current. In closed-loop operation, R40 or R16 adjusts the maximum laser bias current. R16 R40 APC For closed-loop operation, R40 or R16 adjusts the monitor diode current level. TP1 TP10 Fail Indicator D1 D3 Fail Indicator Electrical output. TTL low level indicates a failure in the APC loop. Refer to the Design Procedure section of the MAX3850 data sheet. Set APC current, then increase bias current until the LED goes off (the LED is illuminated when the APC loop is open, and off when the APC loop is closed). _______________________________________________________________________________________ 3 Evaluates: MAX3850 7) If the latch is enabled, apply a differential clock signal (max amplitude ≤ 800mV per side) to J5 and J6 (CLK+ and CLK-). Evaluates: MAX3850 MAX3850 Evaluation Kit Note: When performing resistance checks, manually set the ohmmeter to a high resistance range to avoid forward-biasing the on-chip ESD protection diodes. 9) Attach the laser diode fiber connector to an optical/electrical converter. 4) Adjust R14, the MODSET potentiometer, for maximum resistance between test point 5 and ground. 11) Adjust R15 until the LED (D1) no longer is illuminated. Optical power can be observed on an oscilloscope connected to an optical/electrical converter. 5) Adjust R15, the BIASMAX potentiometer, for maximum resistance between test point 4 and ground. 6) Adjust R16, the APCSET potentiometer, for desired optical power. (Refer to the Design Procedure section of the MAX3850 data sheet. Note that R3 adds 1kΩ to the total resistance.) 10) Power up the board with a +3.3V supply. 12) Adjust R14 until the desired optical amplitude is achieved. Optical amplitude can be observed on an oscilloscope connected to an optical/electrical converter. 7) Apply a differential input signal (max amplitude ≤ 800mV per side) to J1 and J2 (DATA+ and DATA-). 8) Apply a differential clock signal (max amplitude ≤ 800mV per side) to J3 and J4 (CLK+ and CLK-). 4 _______________________________________________________________________________________ MAX3850 Evaluation Kit CONFIGURATION 2 TOP OF PC BOARD LD TOP OF PC BOARD LD TO-46 CAN LASER/PHOTODIODE PAIR TO-46 CAN LASER/PHOTODIODE PAIR BOTTOM OF PC BOARD BOTTOM OF PC BOARD PD SOLDER BRIDGES VCC PD SOLDER BRIDGES VCC CONFIGURATION 3 CONFIGURATION 4 TOP OF PC BOARD TOP OF PC BOARD LD TO-46 CAN LASER/PHOTODIODE PAIR TO-46 CAN LASER/PHOTODIODE PAIR BOTTOM OF PC BOARD PD BOTTOM OF PC BOARD VCC Evaluates: MAX3850 CONFIGURATION 1 LD PD VCC SOLDER BRIDGES SOLDER BRIDGES PAD LAYOUT GND VCC VCC GND GND VCC VCC GND Figure 1. Attachment of Laser/Monitor Diode to the MAX3850 EV Kit _______________________________________________________________________________________ 5 GND VCC CLK- CLK+ DATA- DATA+ TP22 J6 J8 J5 J7 L9 220nH R28 100Ω C30 0.1µF R32 100Ω C29 0.1µF C27 0.1µF C26 0.1µF C40 10µF JU5 JU4 C28 0.01µF C41 0.01µF VCC VCC 8 7 6 5 4 3 VCC LATCH VCC1 CLK- CLK+ VCC1 DATA- R37 392Ω 9 31 R22 1.5kΩ 32 TP2 VCC VCC1 2 DATA+ 1 C24 0.01µF R5 1.5kΩ R42 200kΩ 30 Figure 2. MAX3850 EV Kit Electrical Configuration Schematic _______________________________________________________________________________________ 28 13 R43 392Ω TP10 12 27 R23 1kΩ MAX3850 U2 29 TP18 11 TP17 10 BIASMAX GND TP21 VCC VCC2 ENABLE TP3 MODSET BIASMON R41 50kΩ MODMON TP11 N.C. FAIL R38 49.9Ω APCSET TP8 GND 26 25 VCC VCC 16 R34 110Ω C33 0.1µF 15 D3 LED 14 APCFILT R40 100kΩ VCC3 CAPC GND 6 VCC4 17 18 19 20 21 22 23 24 VCC VCC BIAS VCC4 OUT+ OUT- VCC4 GNDM GND3 MD TP12 BIAS GND GND MD VCC VCC C32 0.01µF C25 0.01µF C42 0.1µF 1 6 C7 0.5pF C8 1.0pF C43 1000pF Q2 GND 3 2 C45 0.01µF 3 2 MD R6 OPEN R17 30.1Ω 4 7 U3 VCC R47 1.5kΩ VCC R46 15Ω TP13 BIAS R49 75Ω Z0 = 30 Z0 = 30 R4 30.1Ω APC TEST CIRCUIT MAX495 VCC R44 30.1Ω J9 OUT Evaluates: MAX3850 MAX3850 Evaluation Kit GND CLK- CLK+ DATA- DATA+ TP20 TP19 J4 J2 J3 J1 L4 220nH R8 100Ω C13 0.1µF R12 100Ω C12 0.1µF C11 0.1µF C10 0.1µF C19 10µF JU2 JU1 C3 0.01µF C20 0.01µF VCC1 VCC1 2 DATA+ 3 DATA4 VCC1 5 CLK+ 6 CLK7 VCC1 8 LATCH 1 VCC1 VCC1 9 31 R2 1.5kΩ 32 TP4 R19 TP15 392Ω VCC1 C2 0.01µF R1 1.5kΩ R15 200kΩ 30 10 TP16 11 BIASMAX GND VCC VCC2 ENABLE TP5 MODSET BIASMON R14 50kΩ 28 13 R35 392Ω R18 110Ω TP1 12 27 R3 1kΩ MAX3850 U1 29 APCSET MODMON VCC1 GND 25 VCC1 26 15 VCC1 VCC1 D1 14 APCFILT TP14 16 CAPC GND R21 49.9Ω VCC3 VCC4 TP6 N.C. FAIL C4 0.01µF VCC1 BIAS VCC4 OUT+ OUT- VCC4 GNDM GND3 MD GND L2 R20 11Ω C6 VCC1 1000pF MURATA BLM18HG601SNI C35 8.2pF R36 49.9Ω R27 16.2Ω GND VCC1 VCC1 VCC1 C5 0.1µF 17 18 19 20 21 22 23 24 C1 0.01µF C16 0.1µF SB1 SB2 3 LASER U4* 1 C17 0.01µF C36 0.01µF C38 0.01µF C22 0.01µF *NOTE: SEE FIGURE 1 FOR DETAILS OF U4 CONNECTION 2 6 5 4 PHOTODIODE VCC1 SB4 SB5 SB6 SB3 Evaluates: MAX3850 R16 100kΩ MAX3850 Evaluation Kit Figure 3. MAX3850 EV Kit Optical Configuration Schematic _______________________________________________________________________________________ 7 Evaluates: MAX3850 MAX3850 Evaluation Kit 1.0" Figure 4. MAX3850 EV Kit Component Placement Guide— Component Side 8 1.0" Figure 5. MAX3850 EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ MAX3850 Evaluation Kit Evaluates: MAX3850 1.0" 1.0" Figure 6. MAX3850 EV Kit PC Board Layout—Solder Side Figure 7. MAX3850 EV Kit PC Board Layout—Ground Plane _______________________________________________________________________________________ 9 Evaluates: MAX3850 MAX3850 Evaluation Kit 1.0" 1.0" Figure 8. MAX3850 EV Kit PC Board Layout—Power Plane Figure 9. MAX3850 EV Kit Component Placement Guide— 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 ____________________ 10 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.