DEMO MANUAL DC1787A LT3759 Wide Input Voltage Range Boost/SEPIC/Inverting Controller DESCRIPTION Demonstration circuit 1787A is a wide input voltage range SEPIC converter featuring the LT3759 controller. It converts a 2.8V~36V input to a 12V output, with 1A load current capability for VIN ≥ 4V. The converter operates at a 300 kHz nominal switching frequency, with 91% peak efficiency. The DC1787A can be easily modified to generate other output voltages, and can also be optimized for efficiency and size with narrower input voltage ranges. The LT3759 is a boost/SEPIC/Inverting controller with a wide input voltage range, suitable for applications from single-cell lithium-ion battery portable electronics to high voltage automotive and industrial power supplies. It also exhibits low shutdown quiescent current of 1μA, making it an ideal fit for battery-operated systems. Thanks to a novel PERFORMANCE SUMMARY PARAMETER FBX pin architecture, the LT3759 can be connected directly to a divider from either positive output or negative output voltage to ground. It also packs many popular features such as soft-start, input undervoltage lockout, adjustable frequency and synchronization in a small 12-lead exposed pad MSOP package. The LT3759 data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this quick start guide for demo circuit 1787A. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. (TA = 25°C) CONDITIONS Input Voltage Range, VIN MIN TYP 2.8 12 Minimum Startup Voltage MAX UNITS 36 V 3.0 V Switching Frequency IOUT = 0.5A 300 Output Voltage, VOUT VIN = 2.8V~36V IOUT = 0mA~0.5A Maximum Continuous Output Current, IOUT VIN ≥ 2.8V 0.5 A VIN ≥ 4.0V 1 A 11.64 12.0 kHz 12.36 V Output Voltage Ripple (Peak-to-Peak) VIN = 12V, IOUT = 1A 90 mV Typical Efficiency VIN = 12V, IOUT = 1A 91 % dc1787af 1 DEMO MANUAL DC1787A QUICK START PROCEDURE Demo circuit 1787A is easy to set up to evaluate the performance of the LT3759. Refer to Figure 1 for proper measurement equipment setup and follow the procedure. 1. With power off, connect the input power supply to the VIN (E1) and GND (E2) terminals on the demo circuit. NOTE: Minimize the voltage drop and transient on the input wires between the power supply and input terminals of the demo circuit. 2. Connect load to the VOUT (E6) and GND (E5) terminals on the demo circuit. Connect voltage and current meters as shown in Figure 1. Preset the load to 0.5A or less, and VIN supply to be 0V. 3. Place jumpers in the following positions for a typical 12V application: EN (JP1) ON SYNC (JP2) OFF 4. Turn on the power supply at the input. Slowly increase VIN to 3.0V. NOTE: Make sure the input voltage is within the range. If higher operating voltage is required, power components with higher voltage ratings should be used. The maximum input voltage of LT3759 is 42V. NOTE: The demo circuit configures the shutdown voltage at typical 2.5V, which means that the input voltage can be dropped to as low as 2.5V, once it starts up. The startup voltage is 3.0V but can be adjusted by changing R1 and R3 values. 5. Check for the proper output voltages. The output should be regulated at 12V (±3%). NOTE: If there is no output, or output is out of spec, temporarily disconnect the load from the demo board. Make sure the load current is set within spec, and the power supply current capability is above 4A. 6. Once the proper output voltage is established, adjust the input and load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. Typical efficiency curve, regulation, and operation waveforms are shown in Figures 3 and 4, respectively. NOTE: When measuring the input or output voltage ripples, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output voltage ripple by touching the probe tip directly across the VIN and GND, or VOUT and GND terminals. See Figure 2 for proper scope probe technique. NOTE: The output current capability depends on the input voltage, as can be seen in Figure 3. Proper cooling is necessary for overload operations. dc1787af 2 DEMO MANUAL DC1787A QUICK START PROCEDURE dc1787af F01 Figure 1. Proper Measurement Equipment Setup INPUT OR OUTPUT CAPACITOR dc1787af F02 Figure 2. Proper Scope Probe Placement for Measuring Input or Output Ripple 95 EFFICIENCY (%) 90 VO: 10V/DIV 85 VDS: 50V/DIV 80 75 ISW: 5A/DIV VIN = 2.8V VIN = 4V VIN = 12V 70 100 200 300 400 500 600 700 800 900 1000 LOAD CURRENT (mA) dc1787af F04 dc1787af F03 Figure 3. Efficiency Curves Figure 4. Short Circuit Waveforms with Frequency Foldback dc1787af 3 DEMO MANUAL DC1787A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 2 CIN1, CIN2 CAP., X7R, 10μF, 50V, 10%, 1210 MURATA, GRM32ER71H106KA12L 2 1 CIN3 CAP., ELECT., 22μF, 50V, C-CE-BS-6.3X6.0 SUN ELECT., 50CE22BS 3 2 COUT1, COUT2 CAP., X5R, 47μF, 16V, 10%, 1210 MURATA, GRM32ER61C476KE15L 4 1 C1 CAP., X7R, 4.7μF, 50V, 20%, 1210 MURATA, GRM32ER71H475KA88L 5 1 C2 CAP., X7R, 1μF, 50V 10%, 0805 MURATA, GRM21BR71H105KA12L 6 1 C3 CAP., X5R, 4.7μF, 16V, 10%, 0805 MURATA, GRM219R61C475KE15D 7 1 C5 CAP., X7R, 68nF, 50V, 0603 NIC, NMC0603X7R682K50F 8 1 C6 CAP., X7R, 0.1μF, 25V, 10%, 0603 TDK, C1608X7R1E104K 9 1 C7 CAP., C0G, 470pF, 50V, 5%, 0603 MURATA, GCM1885C1H471JA16D 10 1 D3 DIODE, SCHOTTKY, 3A, POWERDI5 DIODES/ZETEX, PDS360-13 11 1 L1 IND, 15μH, L-DUAL-DRQ127 COILTRONICS, DRQ127-150-R 12 1 Q1 MOSFET, N-CHANNEL, LFPAK RENESAS, RJK0652DPB-00-J5 13 1 RCS RES SENSE, 0.005Ω, 1/2W, 1%, 2010 VISHAY, WSL20105L000FEA 14 1 RFBB RES., CHIP, 15.8k, 1/16W, 1%, 0603 VISHAY, CRCW060315K8FKEA 15 1 RFBS RES., CHIP, 102k, 1/16W, 1%, 0603 VISHAY, CRCW0603102KFKEA 16 1 R1 RES., CHIP, 249k, 1/16W, 1%, 0603 VISHAY, CRCW0603249KFKEA 17 1 R2 RES., CHIP, 100k, 1/16W, 5%, 0603 VISHAY, CRCW0603100KJNEA 18 1 R3 RES., CHIP, 255k, 1/16W, 1%, 0603 VISHAY, CRCW0603255KFKEA 19 1 R4 RES., CHIP, 1.43k, 1/16W, 1%, 0603 VISHAY, CRCW06031K43FKEA 20 1 R5 RES., CHIP, 27.4k, 1/16W, 1%, 0603 VISHAY, CRCW060327K4FKEA 21 1 R6 RES., CHIP, 0Ω, 0603 VISHAY, CRCW06030000Z0ED 22 1 U1 I.C. LT3759EMSE, MSE12 LINEAR TECH.,LT3759EMSE Hardware/Components (For Demo Board Only) 1 7 E1, E2, E3, E4, E5, E6, E7 TESTPOINT, TURRET, .094" MILL-MAX, 2501-2-00-80-00-00-07-0 2 2 JP1, JP2 JMP, 3-PIN, 1 ROW .079CC SAMTEC, TMM-103-02-L-S 3 2 SHUNTS AS SHOWN ON ASSY DWG SHUNT, .079" CENTER SAMTEC, 2SN-BK-G 4 2 STENCILS BOTH SIDES DC1787A-2 Additional Demo Board Circuit Components 1 0 D1 DIODE, FAST SWITCHING, 1N4148WT, SOD523F OPT dc1787af 4 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. A B C EN/UVLO PGOOD GND E1 VIN RUN SHDN JP1 1 2 3 EN/UVLO PGOOD SUN ELECT 50CE22BS 22uF 50V + CIN3 CIN1 10uF 50V 1210 C6 0.1uF CIN2 10uF 50V 1210 C7 470pF R3 255k R4 1.43k C5 68nF 0805 5 2. INSTALL SHUNTS AS SHOWN. 1. ALL RESISTORS ARE IN OHMS, 0603. ALL CAPACITORS ARE IN MICROFARADS, 0603. 4 R5 27.4k 4 1 3 9 12 11 RT VC SS INTVCC SENSE GATE DRIVE 7 8 10 RFBB 15.8k RFBS 102k +VOUT C2 1uF 50V 0805 1 R6 0 +VOUT OPT 4 D1 1N4148WT 2 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. L1B 15uH APPROVALS SCALE = NONE 2 3 2 1 COUT1 47uF 16V 1210 1 3 2 1 JP2 * * SYNC VIN > 4V 1A +VOUT 12V / VIN > 2.8V E7 E6 GND DATE 09-30-11 0.5A +VOUT E5 ZHONGMING Y. APPROVED 2 DATE: N/A SIZE IC NO. 09/30/2011, 12:52 PM LT3759EMSE DEMO CIRCUIT 1787A 1 SHEET 1 OF 1 2 REV. SEPIC CONVERTER WITH WIDE INPUT VOLTAGE RANGE 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only OFF ON SYNC COUT2 47uF 16V 1210 PRODUCTION DESCRIPTION REVISION HISTORY TECHNOLOGY REV D3 PDS360 1 _ ECO TITLE: SCHEMATIC Q1 RJK0652DPB 1210 C1 4.7uF 50V RCS 0.005 2010 L1A 15uH DRQ127-150-R 3 1 LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. KIM T. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. ZHONGMING Y. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. CUSTOMER NOTICE R2 100k EN/UVLO VIN U1 LT3759EMSE C3 4.7uF 16V R1 249k NOTES: UNLESS OTHERWISE SPECIFIED E4 E3 E2 VIN 2.8V - 36V 3 4 2 D 4 6 PGOOD GND 13 2 FBX SYNC 5 5 1 2 3 5 A B C D DEMO MANUAL DC1787A SCHEMATIC DIAGRAM dc1787af 5 DEMO MANUAL DC1787A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright © 2004, Linear Technology Corporation dc1787af 6 Linear Technology Corporation LT 1111 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2011