DEMO MANUAL DC1749B LT8610 42V, 2.5A Micropower Synchronous Step-Down Regulator Description Demonstration circuit 1749B is a 42V, 2.5A micropower synchronous step-down regulator featuring the LT®8610. The LT8610 is a compact, high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 2.5µA of quiescent current when output is regulated at 5V. Top and bottom power switches, compensation components and other necessary circuits are inside of the LT8610 to minimize external components and simplify design. The demo board has an EMI filter installed. The EMI performance of the board is shown on Figure 2. The limit in Figure 2 is EN55022 class B, average. It shows the circuit passes the test with a wide margin. The SYNC pin on the demo board is grounded by default for low ripple Burst Mode® operation. To synchronous to an external clock, move JP1 to SYNC and apply the external clock to the SYNC turret. Once JP1 is on SYNC position, a DC voltage of higher than 2V or INTVCC can be applied Design files for this circuit board are available at http://www.linear.com/demo/DC1749B The LT8610 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 1749B. L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. 70 95 60 90 50 85 40 80 30 75 20 10 70 0 65 60 MKR1 2.003MHz 21.69 dBµV 10 dB/DIV 80 100 EFFICIENCY (%) to the SYNC turret for pulse-skipping operation. Figure 1 shows the efficiency of the circuit at 12V input. –10 0 0.5 1.5 1 LOAD CURRENT (A) 2 2.5 dc1749b F01 Figure 1. LT8610 12VIN to 5VOUT Efficiency at 2MHz Switching Frequency START 150kHz RES BW (CISPR) 9kHz VBW 62kHz STOP 30MHz SWEEP 717ms (6637 PTS) dc1749b F02 Figure 2. LT8610 Demo Circuit EMI Performance, Switching Frequency = 2MHz dc1749bfa 1 DEMO MANUAL DC1749B Performance Summary Specifications are at TA = 25°C SYMBOL PARAMETER CONDITIONS MIN VIN Input Supply Range 5.5 VOUT Output Voltage 4.8 IOUT Maximum Output Current 2.5 FSW Switching Frequency 1.85 EFE Efficiency at DC IOUT = 1A TYP 5 MAX UNITS 42 V 5.2 V A 2 2.15 MHz 92 % Quick Start Procedure Demonstration circuit 1749B is easy to set up to evaluate the performance of the LT8610. Refer to Figure 3 and Figure 4 for proper measurement equipment setup and follow the procedure below: 2.With power off, connect the load VOUT and GND. 1.With power off, connect the input power supply to VIN and GND. 5.Carefully evaluate other design parameters as needed. 3.Check JP1 setting 4.Turn on the power at the input. DC1749b F03 Figure 3. Proper Measurement Equipment Setup dc1749bfa 2 DEMO MANUAL DC1749B Quick Start Procedure DC1749b F04 Figure 4. Measure Output Ripple dc1749bfa 3 DEMO MANUAL DC1749B Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C2 CAP, X7R, 4.7µF, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L 2 1 C4 CAP, X7R, 0.22µF, 16V, 10%, 0603 AVX, 0603YC224KAT2A 3 1 C5 CAP, C0G, 10pF, 25V, 10%, 0402 AVX, 04023A100KAT2A 4 1 C6 CAP, X7R, 47µF, 10V, 10%, 1210 MURATA, GRM32ER71A476KE20L 5 1 C7 CAP, X7R, 1µF, 25V, 10%, 0603 MURATA, GRM188R71E105KA12D 6 1 C8 CAP, X7R, 0.1µF, 16V, 10%, 0402 MURATA, GRM155R71C104KA88D 7 1 L1 IND, 2.2UH COILCRAFT, XAL5030-222MEC 8 1 R2 RES, CHIP, 18.2k, 1/10W, 1%, 0603 VISHAY, CRCW060318K2FKED 9 1 R3 RES, CHIP, 49.9k, 1/16W, 1%, 0402 VISHAY, CRCW040249K9FKED 10 2 R1, R4 RES, CHIP, 1M, 1/16W, 1%, 0402 VISHAY, CRCW04021M00FKED 11 1 R5 RES, CHIP, 243k, 1/16W, 1%, 0402 VISHAY, CRCW0402243KFKED 12 1 U1 IC, LT8610EMSE, MSE16 LINEAR TECHNOLOGY CORPORATION, LT8610EMSE CAP, ALUM, 22µF, 63V SUN ELECT, 63CE22BS Additional Demo Board Circuit Components 1 1 C1 2 2 C3, C10 CAP, X7R, 4.7µF, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L 3 1 C9 CAP, X7R, 4.7µF, 16V, 10%, 0805 MURATA, GRM21BR71C475K73L 4 1 C11 CAP, X7R, 1µF, 50V, 10%, 0805 TDK, C2012X7R1H105K 5 2 C12, C13 CAP, X7R, 0.1µF, 50V, 10%, 0402 TDK, C1005X7R1H104K 6 1 FB1 FERRITE BEAD, 0805 TDK, MPZ2012S221A 7 1 L2 IND 4.7UH VISHAY, IHLP2020BZ-ER4R7M01 8 0 R6 RES, OPT, 0402 OPT Hardware: For Demo Board Only 1 9 E1 TO E9 TESTPOINT, TURRET, 0.094" MILL-MAX, 2501-2-00-80-00-00-07-0 2 1 JP1 HEADER 1X3 079 SAMTEC, TMM-103-02-L-S 3 1 XJP1 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G 4 4 MH1 TO MH4 STAND-OFF, NYLON 0.50" TALL KEYSTONE, 8833 (SNAP ON) dc1749bfa 4 DEMO MANUAL DC1749B Schematic Diagram dc1749bfa 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. 5 DEMO MANUAL DC1749B 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 dc1749bfa 6 Linear Technology Corporation LT 1113 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2012