DEMO MANUAL DC2275A LT8331 Boost/SEPIC/Inverting Regulator DESCRIPTION Demonstration circuit DC2275A features the LT®8331 in boost configuration. The demo circuit demonstrates small size and low component count. The boost is designed to convert a 10V to 48V source to 120V at 25mA to 80mA. DC2275A includes an optional circuit on the back of the board for a charge pump that can be used to double the output voltage. The default mode for this application is pulse-skip mode, but removal of R13 allows for other modes to be used for different applications. A jumper from sync to ground will put the converter in Burst Mode® operation, or an external clock can be used to synchronize the converter to an external frequency. PERFORMANCE SUMMARY SYMBOL PARAMETER VIN Input Supply Range VOUT Output Voltage Range The LT8331 can operate with inputs as high as 100V but in this demo circuit, the input is limited by the voltage rating of the input capacitor. The LT8331 includes many other features such as synchronization to external clock, user configurable undervoltage lockout, soft-start, frequency foldback, and it is easily configured as boost, SEPIC or inverting converter. The data sheet gives a complete description of the device, operation and application information. The data sheet must be read in conjunction with this demo manual for DC2275A. Design files for this circuit board are available at http://www.linear.com/demo/DC2275A L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Specifications are at TA = 25°C CONDITIONS MIN TYP 10 VIN = 12V, ILOAD = 30mA 116.4 MAX 48 120 123.6 UNITS V V RIPPLE VIN = 12V, ILOAD = 30mA 200 mV EFFICIENCY VIN = 24V, ILOAD = 55mA 90 % EFFICIENCY VIN = 12V, ILOAD = 30mA SWITCHING FREQUENCY 79 % 200 kHz dc2275af 1 DEMO MANUAL DC2275A QUICK START PROCEDURE Demonstration circuit DC2275A is easy to set up to evaluate the performance of the LT8331. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: NOTE: When measuring the input or output voltage ripple, 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 or VOUT and GND terminals. See Figure 3 for proper scope probe technique. 1. With power off, connect the input power supply to VIN and GND. 2. Turn on the power at the input. NOTE: Make sure that the input voltage does not exceed 48V. 3. Check for the proper output voltage. NOTE: If there is no output, temporarily disconnect the load to make sure that the load is not set too high. 4. Once the proper output voltages are established, adjust the load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. Figure 1. DC2275A Proper Equipment Setup dc2275af 2 DEMO MANUAL DC2275A QUICK START PROCEDURE GND VIN Figure 2. Measuring Input or Output Ripple 100 90 VIN = 24V EFFICIENCY (%) 80 VIN = 12V 70 60 50 40 30 20 10 0 5 10 15 20 25 30 35 40 45 50 55 60 LOAD CURRENT (mA) dc2275 F03 Figure 3. Efficiency vs Load dc2275af 3 DEMO MANUAL DC2275A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C3 CAP., X5R 10µF 50V 10% 1206 MURATA, GRM31CR61H106KA12L 2 2 C4, C5 CAP., X7R 1µF 250V 10% 2220 MURATA, GRM55DR72E105KW01L 3 1 C6 CAP., X7R 0.22µF 25V 10% 0603 MURATA, GRM188R71E224KA88D 4 1 C7 CAP., X5R 1µF 25V 20% 0603 AVX, 06033D105MAT2A 5 1 C8 CAP., C0G, 4.7pF, 250V, ±0.25pF, 0805 MURATA, GQM2195C2E4R7CB12J 6 1 D3 DIODE, SCHOTTKY, SOD123 DIODES INC., BAV21W-7-F 7 1 L1 INDUCTOR, 330µH ± 20% SUMIDA, CDRH8D43RT125NP-331MC 8 1 R3 RES., CHIP 1M 0.1W 5% 0603 VISHAY, CRCW06031M00JNEA 9 1 R5 RES., CHIP 1M 0.125W 1% 0805 VISHAY, CRCW08051M00FKEA 10 1 R7 RES., CHIP 13.3k 0.1W 1% 0603 VISHAY, CRCW060313K3FKEA 11 1 R8 RES., CHIP 154k 0.1W 1% 0603 VISHAY, CRCW0603154KFKEA 12 1 R12 RES., CHIP 215k 0.1W 1% 0603 VISHAY, CRCW0603215KFKEA 13 1 R13 RES., CHIP 0Ω 0.1W 1% 0603 VISHAY, CRCW06030000Z0EA 14 1 U1 I.C., CONVERTER CONTROLLER LINEAR TECH. CORP. LT8331EMSE 15 1 FAB, PRINTED CIRCUIT BOARD DEMO CIRCUIT 2275A Additional Demo Board Circuit Components 1 0 C1 (Opt) CAP., 1206 2 0 C2 (OPT) CAP., 2220 4 0 D1, D2 (OPT) DIODE, SOD123 5 0 R2 (OPT) RES., 1206 6 0 R6 (OPT) RES., 0603 Hardware: For Demo Board Only 1 7 E1, E2, E3, E4, E5, E6, E7 TURRET, TESTPOINT MILL-MAX, 2501-2-00-80-00-00-07-0 2 4 MH1-MH4 STANDOFF, NYLON 0.25" KEYSTONE, 8831 (SNAP-ON) dc2275af 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 D GND SYNC EN/UVLO GND VIN 10V ‐ 48V 5 E4 E3 E5 E2 E1 5 R12 215K 1% R6 (Opt) R13 0 INTVCC R3 1M 10 11 R8 154k 1% C6 0.22µF 1 12 C3 10µF 50V 1206 BIAS VIN 4 RT SS SYNC 5 9 14 16 70mA 80mA 48V 30mA 12V 55mA 25mA 10V 36V IOUT C4 1µF 250V 2220 VIN * BAV21W‐7‐F D3 R2 OPT 1206 OPT OPT 1206 D2 OPT D1 C1 24V 3 R7 13.3K 1% 2 C2 OPT 2220 2 C5 1µF 250V 2220 OPTIONAL CIRCUIT 17 C7 1µF INTVCC CDRH8D43RT125NP‐331MC L1 330µH Sumida 3 GND 6 NC 8 NC INTVCC FBX SW U1 LT8331EMSE SW 7 3 UVLO 4 R5 0805 1M 0805 4.7pF C8 E7 E6 GND 1 120V VOUT 1 * A B C D DEMO MANUAL DC2275A SCHEMATIC DIAGRAM dc2275af 5 DEMO MANUAL DC2275A 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 dc2275af 6 Linear Technology Corporation LT 1015 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2015