MAX3646EVKIT

19-3194; Rev 0, 2/04 MAX3646 Evaluation Kit ________________________ Features The MAX3646 evaluation kit (EV kit) is an assembled demonstration board that provides complete optical and electrical evaluation of the MAX3646. 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 MAX3646EVKIT -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: MAX3646 _______________ General Description MAX3646 Evaluation Kit Evaluates: MAX3646 _______________________________Electrical Evaluation Component List (cont.) DESIGNATION U2 QTY 1 U3 1 None None None 7 1 1 DESCRIPTION MAX495ESA (8 SO) MAX3646ETJ (24 Thin QFN) Shunts MAX3646 EV board MAX3646 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 MAX3646EGJ (32 QFN) 12 Test points 1 1 1 Shunt MAX3646 EV board MAX3646 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 MAX3646 when contacting these component suppliers. 2 _________________________________________________________________________________________ MAX3646 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 155Mbps differential input signal (200mVP-P to 2400mVP-P) between SMA connectors J1 and J2 (IN+ and IN-). Optical Evaluation For optical evaluation of the MAX3646, 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: MAX3646 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 MAX3646. Evaluates: MAX3646 MAX3646 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 (