DEMO CIRCUIT 950A LT3825START AND LT3837 QUICK GUIDE LT3825 and LT3837 Non-opto Synchronous Flyback Controller DESCRIPTION Demonstration circuit 950A is a 30W multi-output synchronous flyback converter in 1/8 brick format featuring the LT3825 and LT3837. Output voltage sensing is implemented without the use of opto-coupler, by sensing the voltage across a primary side auxiliary winding. A load compensation circuit is used to compensate for voltage drops caused by load currents. DC950A-A has input voltage range 36V-72V and features the LT3825. DC950A-B has input voltage range 9V-36V and features the LT3837. Demonstration circuit 950A uses a transformer design with tapped secondary winding, to achieve higher efficiency and better cross regulation than is possible with a transformer that uses a separate winding for each output. Design files for this circuit board are available. Call the LTC factory. L, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered trademarks of Linear Technology Corporation. Adaptive Power, C-Load, DirectSense, Easy Drive, FilterCAD, Hot Swap, LinearView, µModule, Micropower SwitcherCAD, Multimode Dimming, No Latency ∆Σ, No Latency Delta-Sigma, No RSENSE, Operational Filter, PanelProtect, PowerPath, PowerSOT, SmartStart, SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT, UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names may be trademarks of the companies that manufacture the products. PERFORMANCE SUMMARY Specifications are at TA = 25°C SYMBOL VIN PARAMETER Input Supply Range VOUT Output Voltage IOUT Output Current (Note: Total output power not to exceed 30W) Efficiency Efficiency CONDITIONS DC950A-A DC950A-B VOUT1 VOUT2 VOUT3 IOUT1 (5V output) IOUT2 (3.3V output) IOUT3 (2.5V output) DC950A-A,VIN=48V,IOUT1=2A,IOUT1=3A,IOUT3=3A DC950A-B,VIN=24V,IOUT1=2A,IOUT1=3A,IOUT3=3A MIN 36 9 4.85 3.20 2.42 0 0 0 TYP 5V 3.3V 2.5V 2 3 3 90 89 MAX 72 36 5.15 3.40 2.58 4 4 4 UNITS V V V V V A A A % % EQUIPMENT 8 DMMs 1 DC Supply 0-72V 1A for DC950A-A test 1 DC Supply 0-36V 5A for DC950A-B test 3 Adjustable loads 0-3A 1 LT3825 AND LT3837 GETTING STARTED Demonstration circuit 950A is easy to set up to evaluate the performance of the LT3825 and LT3837. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: 1. With power off, connect the input power supply to Vin and GND. 3. Check for the proper output voltages. Vout1 = 5V, Vout2 = 3.3V, Vout3 = 2.5V. 4. Adjust the loads and study the performance of the circuit. Note that the load current should not exceed 4A, and the total load on the three outputs should not exceed 30W continuous power. 2. With no loads, adjust input voltage to be within the input voltage range (36V-72V for DC950A-A, 9V-36V for DC950A-B) and turn on the power at the input. Figure 1. Proper Measurement Equipment Setup 2 LT3825 AND LT3837 3 LT3825 AND LT3837 DC950A-A BILL OF MATERIAL Item Qty Reference Part Description REQUIRED CIRCUIT COMPONENTS1 1 1 C38 Capacitor, NP0, 33pF, 50V, 0603 2 1 C41 Capacitor, NPO, 330PF, 50V, 0603 3 1 C1 Capacitor, NPO 330PF 100V 1206 4 2 C34,C30 Capacitor, X7R, 2200pF, 50V, 0603 5 3 C19,C31,C32 Capacitor, X5R, 0.1uF, 25V, 0603 6 1 C40 Capacitor, X7R, 1000pF, 50V, 0603 7 1 C36 Capacitor, X5R, 0.47uF, 16V, 0603 8 6 C3,C4,C13,C14,C26,C27 Capacitor, X5R, 47uF, 6.3V, 1210 9 0 C33,C39 Capacitor, 0603 10 1 C35 Capacitor, X7R, 3300PF, 50V, 0603 11 1 C37 Capacitor, NPO, 680PF, 50V, 0603 12 1 C9 Capacitor, NPO, 150pF, 200V, 1206 13 1 C18 Capacitor, X7R, 22uF, 16V, 1210 14 2 C20,C21 Capacitor, X7R, 2.2uF, 100V, 1812 15 1 D2 BAS21 16 2 D8,D6 BAT54 17 1 D5 BAT54A 18 1 D10 BAT54S 19 1 D9 B0530W 20 0 D4 Zenerdiode, 12V, 5%, SOT23 21 1 L5 Inductor, 330uH 22 1 L6 Inductor, 120uH 23 1 Q1 MOSFET, n-ch, SO8 24 1 Q3 MOSFET, n-ch, SO8 25 2 Q7,Q9 Transistor, npn, SOT23 26 3 Q8,Q10,Q12 Transistor, pnp, SOT23 27 0 Q4 Transistor, npn, SOT23 28 1 Q5 MOSFET, n-ch, SO8 29 1 Q6 MOSFET, n-ch, SO8 30 1 R11 Resistor, 0 OHMS 0603 31 1 R2 Resistor, 18 OHMS 1206 32 2 R21,R16 Resistor, 15 OHMS 0603 33 1 R15 Resistor, 330 OHMS 0603 34 2 R9,R29 Resistor, 1.00k, 0603 35 1 R14 Resistor, 1.00k, 0805 36 1 R22 Resistor, 3.01K, 0603 37 1 R30 Resistor, 4.64K, 0603 38 3 R19,R23,R28 Resistor, 10.0K, 0603 39 1 R12 Resistor, 28.7K, 0805 40 1 R25 Resistor, 100K, 0603 41 1 R27 Resistor, 150K, 0603 42 1 R5 Resistor, 22 OHM, 1206 43 1 R17 Resistor, 0.025 OHM 1% 1206 44 1 R26 Resistor, 1.00K, 0603 45 1 R6 Resistor, 47K, 1206 46 1 R13 Resistor, 402K, 0805 47 0 R4,R18 Resistor, 1206 48 1 R8 Resistor, 91 OHMS 0805 49 1 R20 Resistor, 14.7K, 0603 50 1 R24 Resistor, 12.4K, 0603 4 Manufacture / Part # AVX, 06035A330KAT2 AVX, 06035A331KAT AVX, 12061A331KAT AVX, 06035C222JAT AVX, 06033D104KAT2A AVX, 06035C102KAT2A AVX, 0603YD474M TDK, 3225X5R0J476M OPT KEMET, C0603C332J5RAC AVX, 06035A681JAT AVX, 12062A151KAT2A TDK, C3225RX7R1C226M TDK, C4532X7R2A225M Diodes, Inc.,BAS21-7-F Diodes, Inc.,BAT54-7-F Diodes, Inc.,BAT54A-7 Diodes, Inc.,BAT54S-7-F Diodes, Inc.,B0530W-7-F OPT Coilcraft, DO1608C-334MLB Wurth Elektronik, 744 032 121 Vishay, Si4850EY-T1-E3 Vishay, Si4840DY-T1-E3 Zetex, FMMT619TA Zetex, FMMT718TA OPT Vishay, Si4840DY-T1-E3 Vishay, Si4488DY-T1-E3 VISHAY, CRCW06030000Z0EA VISHAY, CRCW120618R0JNEA VISHAY, CRCW060315R0FKEA VISHAY, CRCW0603330RFKEA VISHAY, CRCW06031K0FKED VISHAY, CRCW08051K0FKED VISHAY, CRCW06033011FRT6 VISHAY, CRCW06034K64FKED VISHAY, CRCW060310K0FKED VISHAY, CRCW080528K7FKED VISHAY, CRCW0603100KJNEA VISHAY, CRCW0603150KJNEA VISHAY, CRCW120622ROJNEA IRC, LRF1206LF-01-R025-F VISHAY, CRCW06031K00FKEA VISHAY, CRCW120647K0JNEA VISHAY, CRCW0805402KFKEA OPT VISHAY, CRCW080591R0FKEA VISHAY, CRCW060314K7FKEA VISHAY, CRCW060312K4FKEA LT3825 AND LT3837 51 52 53 1 1 1 T2 T1 U1 Gatedrive transformer EFD20 Flyback transformer LT3825EFE#PBF ADDITIONAL DEMO BOARD CIRCUIT COMPONENTS2 1 1 C8 Capacitor, electrolytic, 12UF, 100V 2 3 C7,C17,C23 Capacitor, TANT, 100uF, 6.3V, 3528 3 1 C43 Capacitor, X7R, 4700pF 250V, 1812 4 3 L1,L3,L4 Inductor, 0.2uH 5 1 L2 Inductor, 4.7uH HARDWARE-FOR DEMO BOARD ONLY: 1 4 (STAND-OFF), STAND-OFF, NYLON 0.50" 2 6 E1-E6 Turret, 0.094" Pulse Engineering, PA0173 Pulse Engineering, PA2046NL Linear Technology, LT3825EFE#PBF Sanyo, 100ME12AX+TS Kemet, T520B107M006ASE070 MURATA, GA343DR7GD472KW01L Cooper, FP2-S200 Cooper, HCP0703-4R7-R KEYSTONE, 8833(SNAP ON) Mill-Max, 2501-200-80-00-00-07-0 Notes: 1. Required Circuit Components are those parts that are required to implement the circuit function 2. Additional Demo Board Circuit Components are those parts that provide added functionality for the demo board but are not required in the actual circuit. DC950A-B BILL OF MATERIAL Item Qty Reference Part Description REQUIRED CIRCUIT COMPONENTS1 1 1 C38 Capacitor, NP0, 33pF, 50V, 0603 2 1 C41 Capacitor, NPO, 330PF, 50V, 0603 3 1 C1 Capacitor, NPO 330PF 100V 1206 4 2 C34,C30 Capacitor, X7R, 2200pF, 50V, 0603 5 3 C19,C31,C32 Capacitor, X5R, 0.1uF, 25V, 0603 6 1 C40 Capacitor, X7R, 1000pF, 50V, 0603 7 1 C36 Capacitor, X5R, 0.47uF, 16V, 0603 8 6 C3,C4,C13,C14,C26,C27 Capacitor, X5R, 47uF, 6.3V, 1210 9 0 C33,C39 Capacitor, 0603 10 1 C35 Capacitor, X7R, 3300PF, 50V, 0603 11 1 C37 Capacitor, NPO, 680PF, 50V, 0603 12 1 C9 Capacitor, NPO, 560pF, 100V, 1206 13 0 C18 Capacitor, 1210 14 2 C20,C21 Capacitor, X7R, 4.7uF, 50V, 1812 15 1 D2 BAS21 16 2 D8,D6 BAT54 17 1 D5 BAT54A 18 1 D10 BAT54S 19 1 D9 B0530W 20 1 D4 Zenerdiode, 11V, 5%, SOT23 21 1 L5 Inductor, 330uH 22 1 L6 Inductor, 120uH 23 1 Q1 MOSFET, n-ch, SO8 24 1 Q3 MOSFET, n-ch, SO8 25 2 Q7,Q9 Transistor, npn, SOT23 26 3 Q8,Q10,Q12 Transistor, pnp, SOT23 Manufacture / Part # AVX, 06035A330KAT2 AVX, 06035A331KAT AVX, 12061A331KAT AVX, 06035C222JAT AVX, 06033D104KAT2A AVX, 06035C102KAT2A AVX, 0603YD474M TDK, 3225X5R0J476M OPT KEMET, C0603C332J5RAC AVX, 06035A681JAT AVX, 12061A561KAT2A OPT TDK,C4532X7R1H475MT Diodes, Inc.,BAS21-7-F Diodes, Inc.,BAT54-7-F Diodes, Inc.,BAT54A-7 Diodes, Inc.,BAT54S-7-F Diodes, Inc.,B0530W-7-F Vishay, BZX84C11-V Coilcraft, DO1608C-334MLB Wurth Elektronik, 744 032 121 Vishay, Si4850EY-T1-E3 Vishay, Si4840DY-T1-E3 Zetex, FMMT619TA Zetex, FMMT718TA 5 LT3825 AND LT3837 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 1 1 1 1 1 2 1 2 1 1 1 3 1 1 1 1 2 1 1 1 0 1 1 1 1 1 1 Q4 Q5 Q6 R11 R2 R21,R16 R15 R9,R29 R14 R22 R30 R19,R23,R28 R12 R25 R27 R5 R17,R18 R26 R4 R13 R6 R8 R20 R24 T2 T1 U1 Transistor, npn, SOT23 MOSFET, n-ch, SO8 MOSFET, n-ch, SO8 Resistor, 0 OHMS 0603 Resistor, 18 OHMS 1206 Resistor, 15 OHMS 0603 Resistor, 330 OHMS 0603 Resistor, 1.00k, 0603 Resistor, 1.00k, 0805 Resistor, 3.01K, 0603 Resistor, 4.64K, 0603 Resistor, 10.0K, 0603 Resistor, 28.7K, 0805 Resistor, 100K, 0603 Resistor, 150K, 0603 Resistor, 22 OHM, 1206 Resistor, 0.015 OHM 1% 1206 Resistor, 750 OHMS, 0603 Resistor, 4.7k, 1206 Resistor, 121K, 0805 Resistor, 1206 Resistor, 22.1 OHMS 0805 Resistor, 22.1K, 0603 Resistor, 13.0K, 0603 Gatedrive transformer EFD20 Flyback transformer LT3837EFE#PBF ADDITIONAL DEMO BOARD CIRCUIT COMPONENTS2 1 1 C8 Capacitor, electrolytic, 47UF, 50V 2 3 C7,C17,C23 Capacitor, TANT, 100uF, 6.3V, 3528 3 1 C43 Capacitor, X7R, 4700pF 250V, 1812 4 3 L1,L3,L4 Inductor, 0.2uH 5 1 L2 Inductor, 4.7uH HARDWARE-FOR DEMO BOARD ONLY: 1 4 (STAND-OFF), STAND-OFF, NYLON 0.50" 2 6 E1-E6 Turret, 0.094" MMBT3904LT Renesas, HAT2165H Vishay, Si7852DP-T1-E3 VISHAY, CRCW06030000Z0EA VISHAY, CRCW120618R0JNEA VISHAY, CRCW060315R0FKEA VISHAY, CRCW0603330RFKEA VISHAY, CRCW06031K0FKED VISHAY, CRCW08051K0FKED VISHAY, CRCW06033011FRT6 VISHAY, CRCW06034K64FKED VISHAY, CRCW060310K0FKED VISHAY, CRCW080528K7FKED VISHAY, CRCW0603100KJNEA VISHAY, CRCW0603150KJNEA VISHAY, CRCW120622ROJNEA IRC, LRF1206-01-R015-F VISHAY, CRCW0603750RFKEA VISHAY, CRCW12064K70FKEA VISHAY, CRCW0805121KFKEA OPT VISHAY, CRCW080522R1FKEA VISHAY, CRCW060322K1FKEA VISHAY, CRCW060313K0FKEA Pulse Engineering, PA0173 Pulse Engineering, PA2047NL Linear Technology, LT3837EFE#PBF Sanyo, 50ME47AX+TS Kemet, T520B107M006ASE070 MURATA, GA343DR7GD472KW01L Cooper, FP2-S200 Cooper, HCP0703-4R7-R KEYSTONE, 8833(SNAP ON) Mill-Max, 2501-200-80-00-00-07-0 Notes: 1. Required Circuit Components are those parts that are required to implement the circuit function 2. Additional Demo Board Circuit Components are those parts that provide added functionality for the demo board but are not required in the actual circuit. 6