MAX3740AEVKIT

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The MAX3740A evaluation kit (EV kit) is an assembled demonstration board that provides complete optical and electrical evaluation of the MAX3740A VCSEL driver. I The output of the evaluation kit can be interfaced to an SMA connector, which can be connected to a 50 terminated oscilloscope. With slight modifications, the evaluation kit can also be used to evaluate the MAX3740A operation with a common-cathode VCSEL. m0m0m0m0m0m0m0m0m0m0m0m0m0m0m0m0m0m0m0m nEo5p+qro5s6t5svuxw;yaz{u DESIGNATION QTY DESCRIPTION C1, C2, C5, C9, 0.1µF ±10% ceramic capacitors 8 C13, C15, C16, (0402) C17 ♦ Fully Assembled and Tested ♦ Single +3.3V Power Supply Operation ♦ Allows Optical and Electrical Evaluation W0W0W0W0W0W0W0W0W0W0W0W0W0W0W XZY\[;]TY_^a`;b%cd`6egf5Yihkj6lF^Hf5` PART TEMP. RANGE IC PACKAGE MAX3740AEVKIT -40°C to +85°C 24 QFN DESIGNATION QTY DESCRIPTION R16 1 500kΩ potentiometer Q1, Q2 2 NPN transistors (SOT23) Q3 1 MOSFET (SOT23) JU1–JU8, JU10 9 2-pin headers, 0.1in centers J1–J7 7 SMA connectors, round contacts 1 0.047µF ±10% ceramic capacitor (0402) C4, C6, C7, C8, C11, C12 6 0.01µF ±10% ceramic capacitors (0402) C10 1 Open C14 1 10µF ±10% ceramic capacitor (0805) U1 1 MAX3740AETG (24QFN) U2 1 MAX495ESA (8 SO) C18 1 10µF ±10% tantalum capacitor (B Case) None 9 Shunts D1 1 VCSEL laser and photodiode* None 1 MAX3740A EV board D2 1 LED, red T1 package None 1 MAX3740A data sheet L1, L2, L3 3 L4 1 1µH inductor (1008CS) R1, R2 2 10kΩ potentiometers R3 1 350Ω ±1% resistor (0402) R4 1 2.49kΩ ±1% resistor (0402) R5, R12 2 499Ω ±1% resistors (0402) R6, R13 2 10kΩ ±5% resistors (0402) R7 1 0Ω ±1% resistor (0402)* R8 1 4.7kΩ ±1% resistor (0402) R9, R11 2 49.9Ω ±1% resistors (0402) R10, R26, R27, R34, R35, R36 6 Open R14 1 20kΩ potentiometer R15 1 50kΩ potentiometer      |0|0|0|0|0|0|0|0|0|0|0| }~5€+x~5‚6ƒT‚v„†…ˆ‡Š‰=„Z‹HŒ;~5‚„ŽC   C3 ‘i’R’ “ ”–•˜—™—™š ›œ•žF•FŸR ˜¡'¢™£F¤i£R¥i¦  TP1–TP11, TP20, 13 Test points TP21 * These components are not supplied but can be populated for VCSEL testing. §0§0§0§0§0§0§0§0§0§0§0§0§0§ ¨E©5ª+«r©5¬6­5¬v®¯v°±«;«v²d³H­5´iµ SUPPLIER PHONE FAX AVX 843-444-2863 843-626-3123 Coilcraft 847-639-6400 847-639-1469 Digi-Key 218-681-6674 218-681-3380 EF Johnson 402-474-4800 402-474-4858 Murata 415-964-6321 415-964-8165 Note: Please indicate that you are using the MAX3701 when ordering from these suppliers. _________________________________________________________________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 ¶ ·¸ ¹º»¼· ½¾À¿!Á#Â!¿%ÃÅÄ)Æ+Ç ÈÉÄ.à ÛÚÖ Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0Ü0é±Ü0Ü0êìÌë.Ü0íï.Ü0îñHÜ0ðgÜ òìÌíï.Ý3óôêõÞNéTßHà5öè0ó÷ôá%êìÌø.âxóï.ãåîñHäçòÌìùôæèú ã ØÙ× ÕÖ ÓÔ ÐÒÍÑ ÎÌÍÏ ÌÊ Ë I = MD 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 Q1, which is controlled by an operational amplifier (U2). The APC test circuit, consisting of U2 and Q1, applies the simulated monitor diode current to the MD pin of the MAX3740. To ensure proper operation in the electrical configuration, set up the evaluation board as follows: 1) 2) 3) I BIAS = V 2× R PWRMON PWRSET 9× V 350Ω BIASMON Note: If the voltage at TP1 exceeds VPMTH (0.8V typ) or TP3 exceeds VBMTH (0.8V typ), the FAULT signal will be asserted and latched. Place shunts on JU4 - JU8 and JU10 (see the Adjustment and Control Description section for details). Remove shunts JU1 and JU2. To enable the output connect TX_DISABLE to GND by placing a shunt on JU3. 14) Adjust R2 until the desired laser modulation current is achieved. Note: When performing the following resistance checks, autoranging DMMs may forward bias the onchip ESD protection and cause inaccurate measurements. To avoid this, manually set the DMM to a high range. 15) Adjust R14 (RPEAKSET) until the desired amount of peaking is achieved. 4) Adjust R15, the RBIASSET potentiometer, for 1.7kΩ resistance between TP4 (BIASSET) and ground. 5) Adjust R1, the RPWRSET potentiometer, for 10kΩ resistance between TP2 (REF) and pin 1 (MD) of JU2. 6) Adjust R14, the RPEAKSET potentiometer, for 20kΩ resistance between TP10 (PEAKSET) and ground, to disable peaking. 7) Adjust R16, the RTC potentiometer, for 0Ω resistance between TP7 (TC1) and TP8 (TC2), to disable temperature compensation. 8) Adjust R2, the RMODSET potentiometer, for 10kΩ resistance between TP9 (MODSET) and ground. 9) Apply a differential input signal (250mVP-P to 2200mVP-P) between SMA connectors J5 and J7 (IN+ and IN-). 10) Attach a high-speed oscilloscope with a 50Ω input to SMA connector J6 (OUT). 11) Connect a +3.3V supply between TP20 (VCC) and TP21 (GND). Adjust the power supply until the voltage between TP11 and ground is +3.3V. 12) Adjust R1 (RPWRSET) until desired laser bias current is achieved. I BIAS = V 49.9Ω PIN 1 _ JU 5 13) The MD and BIAS currents can be monitored at TP1 (VPWRMON) and TP3 (VBIASMON) using the equations below: IMOD = Signal Amplitude (V ) 50Ω û'ü5ýHþìÌÿ
  .ýHñþ  For optical evaluation of the MAX3740A, configure the evaluation kit as follows: 1) 2) 3) 4) 5) Place shunts on JU2, JU6, JU7, JU8 and JU10 (See the Adjustment and Control Description section for details). Remove components L2 and C9. Remove the shunts from JU1, JU4 and JU5. Install a 0Ω resistor at R7 to connect the anode of the VCSEL to the output. To enable the output connect TX_DISABLE to GND by placing a shunt on JU3. Connect a common cathode VCSEL as shown in Figure 1. Keep leads short to reduce reflection. Note: When performing the following resistance checks, autoranging DMMs may forward bias the onchip ESD protection and cause inaccurate measurements. To avoid this, manually set the DMM to a high range. 6) 7) 8) 9) Adjust R15, the RBIASSET potentiometer, for 1.7kΩ resistance between TP4 (BIASSET) and ground. Adjust R1, the RPWRSET potentiometer, for 10kΩ resistance between TP2 (REF) and pin 1 (MD) of JU2. Adjust R14, the RPEAKSET potentiometer, for 20kΩ resistance between TP10 (PEAKSET) and ground, to disable peaking. Adjust R16, the RTC potentiometer, for 0Ω resistance between TP7 (TC1) and TP8 (TC2), to disable temperature compensation. 2 ________________________________________________________________________________________  10) Adjust R2, the RMODSET potentiometer, for 10kΩ resistance between TP9 (MODSET) and ground. 11) Apply a differential input signal (250mVP-P to 2200mVP-P) between SMA connectors J5 and J7 (IN+ and IN-). 12) Attach the VCSEL fiber connector to an optical/electrical converter. 13) Connect a +3.3V supply between TP20 (VCC) and TP21 (GND). Adjust the power supply until the voltage between TP11 and ground is +3.3V. 14) Adjust R1 (RPWRSET) until desired average optical power is achieved. 15) The MD and BIAS currents can be monitored at TP1 (VPWRMON) and TP3 (VBIASMON) using the equations below: V I = 2×R PWRMON   I BIAS  "!$#&%(' = )*#
! 9×V 350Ω +, BIASMON -. Note: If the voltage at TP1 exceeds VPMTH (typical 0.8V) or TP3 exceeds VBMTH (typical 0.8V), the FAULT signal will be asserted and latched. 16) Adjust R2 (RMODSET) until the desired optical amplitude is achieved. Optical amplitude can be observed on an oscilloscope connected to an optical/electrical converter. VCSEL overshoot and ringing can be improved by appropriate selection of R10 and C10, as described in the Design Procedure section of the MAX3740 data sheet. MD ;