DEMO MANUAL DC2012A LT8610AB 42V, 3.5A Micropower Synchronous Step-Down Regulator Description Demonstration circuit 2012A is a 42V, 3.5A micropower synchronous step-down regulator featuring the LT®8610AB. The LT8610AB 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. The efficiency of the circuit is greater than 90% at light load up to 1.5A. This is a 10% improvement over competing parts. Top and bottom power switches, compensation components and other necessary circuits are inside of the LT8610AB to minimize external components and simplify design. 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 to the SYNC turret for pulse-skipping operation. Figure 1 shows the efficiency of the circuit at 12V input. Figure 2 shows the thermal performance of the circuit. When running at input voltage greater than 30V, 3.5A output current and 2MHz switching frequency, the temperature rise will be significant. Either reducing the input voltage, the output current or the switching frequency will bring the temperature down to acceptable level without external cooling. The demo board has an EMI filter installed. The board and the IC are designed to minimize conducted and radiated EMI. The conducted EMI performance of the board is shown on Figure 3. The limit in Figure 3 is EN55022 class B, average. It shows the circuit passes the test with a wide margin. The LT8610AB 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 DC2012A. Design files for this circuit board are available at http://www.linear.com/demo/DC2012A 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. Performance Summary Specifications are at TA = 25°C SYMBOL PARAMETER CONDITIONS VIN* Input Supply Range 5.5 VOUT Output Voltage 4.8 IOUT Maximum Output Current 3.5 fSW Switching Frequency EFE Efficiency at DC MIN 1.85 IOUT = 1A TYP MAX UNITS 42 V 5 5.2 V A 2 2.15 91 MHz % * Refer to Figure 2 to determine the maximum input voltage. If IC temperature exceeds target, reduce input voltage, output current or switching frequency. dc2012af 1 DEMO MANUAL DC2012A Quick Start Procedure DC2012A is easy to set up to evaluate the performance of the LT8610AB. Refer to Figure 4 and Figure 5 for proper measurement equipment setup and follow the procedure below: 1.With power off, connect the input power supply to VIN and GND. 2.With power off, connect the load VOUT and GND. 3.Check JP1 setting 4.Turn on the power at the input. 5.Carefully evaluate other design parameters as needed. 140 95 120 CASE TEMPERATURE RISE (°C) 100 EFFICIENCY (%) 90 85 80 75 70 100 65 60 0 0.01 0.1 1 LOAD CURRENT (A) 60 40 700kHz, 3.5A 20 0 10 2MHz, 3.5A 80 2MHz, 2.5A 6 11 16 DC2012A F01 Figure 1. LT8610AB 12VIN to 5VOUT Efficiency at 2MHz Switching Frequency 21 VIN (V) 26 31 36 DC2012A F02 Figure 2. LT8610AB Case Temperature Rise. VOUT = 5V, TA = 25°C 70 60 50 EN55022 CLASS B 40 dBµV 30 20 10 0 –10 –20 –30 START 150kHz RES BW 9kHz VBW 62kHz STOP 30MHz DC2012A F03 Figure 3. LT8610AB Demo Circuit Conducted EMI Performance 2 dc2012af DEMO MANUAL DC2012A Quick Start Procedure Figure 4. Proper Measurement Equipment Setup Figure 5. Measure Output Ripple dc2012af 3 DEMO MANUAL DC2012A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C2 CAP., X7R, 2.2µF, 50V, 10%, 1206 MURATA, GCJ31CR71H225KA12L 2 1 C4 CAP., X7R, 0.22µF, 16V, 10%, 0603 AVX, 0603YC224KAT2A 3 1 C5 CAP., C0G, 10pF, 25V, 10%, 0402 AVX, 04023A100KAT2A 4 2 C6, C14 CAP., X7R, 47µF, 10V, 10%, 1210 MURATA, GRM32ER71A476KE15L 5 1 C7 CAP., X7R, 1.0µF, 25V, 10%, 0603 MURATA, GRM188R71E105KA12D 6 1 C8 CAP., X7R, 0.1µF, 16V, 10%, 0402 MURATA, GRM155R71C104KA88D 7 1 L1 IND., 2.2µH COILCRAFT, XAL5030-222MEC 8 1 R2 RES., CHIP, 18.2k, 1/10W, 1% 0603 VISHAY, CRCW060318K2FKEA 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, LT8610ABEMSE#PBF MSE16 LINEAR TECH, LT8610ABEMSE#PBF Additional Demo Board Circuit Components 1 1 C1 CAP., ALUM, 22µF, 63V SUN ELECT, 63CE22BS 2 2 C3, C10 CAP., X7R, 4.7µF, 50V, 10%, 1206 MURATA, GRM31CR71H475KA12L 3 1 C9 CAP., X7R, 1.0µF, 16V, 10%, 0805 AVX, 0805YC105KAT2A 4 1 C11, C12 CAP., X7R, 0.1µF, 50V, 10%, 0402 TDK, C1005X7R1H104K 5 2 C13 CAP., X7R, 0.1µF, 50V, 10%, 0603 MURATA, GCJ188R71H104KA12D 6 1 FB1 FERRITE BEAD 0805 TDK, MPZ2012S101AT 7 1 L2 IND., 4.7µH VISHAY, IHLP2020BZ-ER4R7M01 8 0 R6 RES., OPT, 0402 OPT Hardware: For Demo Board Only 1 9 E1-E9 TESTPOINT, TURRET, .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, .079" CENTER SAMTEC, 2SN-BK-G 4 4 MH1-MH4 STAND-OFF, NYLON 0.50" TALL KEYSTONE, 8833(SNAP ON) 4 dc2012af 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 GND * VIN 5.5V - 42V E2 E1 5 E7 E9 E5 E6 C12 0.1uF 50V C3 4.7uF 50V 1206 GND SYNC JP1 C10 4.7uF 50V 1206 L2 4.7uH 3 2 1 + C1 22uF 63V SUNCON 63CE22BS 4 * REFER TO THE DEMO MANUAL FOR VIN RANGE. 1. ALL RESISTORS ARE 0402. ALL CAPACITORS ARE 0402. NOTES: UNLESS OTHERWISE SPECIFIED TR/SS GND SYNC EN/UV C11 0.1uF 50V FB1 4 C7 1uF 0603 25V C2 2.2uF 50V 1206 C8 0.1uF C13 0.1uF 50V 0603 R2 18.2k (2MHz) 0603 R6 OPT R1 1M 3 8 7 3 2 13 1 4 6 5 3 GND PGND RT TR/SS INTVCC SYNC EN/UV VIN VIN FB PG BIAS SW SW SW BST U1 LT8610ABEMSE GND 17 D 5 16 15 14 11 10 9 12 2 R5 243k C4 0.22uF 16V 0603 2 C5 49.9k R3 10pF 1Meg R4 XAL5030-222MEC L1 2.2uH C14 47uF 10V 1210 C6 47uF 10V 1210 VOUT 1 1 C9 1uF 16V 0805 E8 E4 E3 PG GND VOUT 5V / 3.5A A B C D DEMO MANUAL DC2012A Schematic Diagram dc2012af 5 DEMO MANUAL DC2012A 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 6 dc2012af Linear Technology Corporation LT 1113 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2013