DEMO MANUAL DC2407A LT8650S Dual Channel 42V, 4A Synchronous Step-Down Silent Switcher with 6.2µA Quiescent Current DESCRIPTION Demonstration circuit 2407A is a dual channel 42V, 4A synchronous step-down Silent Switcher® with 6.2μA quiescent current featuring the LT8650S. The LT8650S is the second-generation Silent Switcher that minimizes EMI and reduces PCB layout sensitivity. The demonstration circuit has two outputs: 5V and 3.3V. Each output can source up to 4A continuous current at the same time. Figure 1 shows the conducted EMI measurements from 150kHz to 30MHz. Figure 2 shows the radiated EMI measurements from 30MHz to 1GHz. All measurements were tested per CISPR 25 specifications. The circuit passes the tests with wide margins. SYNC position and apply the external clock to the SYNC turret. Moving JP2 to FCM W/SSM enables spread spectrum mode. The SYNC pin on the demo board is grounded by default for low ripple Burst Mode® operation. To synchronous to an external clock, move JP2 to FCM W/O SSM OR Design files for this circuit board are available at http://www.linear.com/demo/DC2407A PERFORMANCE SUMMARY The demonstration circuit 2407A runs at 2MHz to minimize solution size. The efficiency is 92%. The IC temperature rise is less than 50°C when both channels run at full load, 4A each, at 2MHz. The LT8650S 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 2407A. L, LT, LTC, LTM, Linear Technology, the Linear logo, Silent Switcher, and Burs Mode are registered trademarks of Analog Devices, Inc. All other trademarks are the property of their respective owners. Specifications are at TA = 25°C SYMBOL PARAMETER VIN Input Supply Range 5.4 4.8 VOUT1 Output1 Voltage IOUT1 Maximum Output1 Current VOUT2 Output2 Voltage IOUT2 Maximum Output2 Current fSW Switching Frequency EFE Efficiency at DC CONDITIONS MIN TYP MAX 42 5 5.2 4 3.168 IOUT1 = 4A, IOUT2 = 4A, Input Voltage = 12V V V A 3.3 3.432 V 2 2.15 MHz 4 1.85 UNITS A 92 % dc2407af 1 DEMO MANUAL DC2407A TYPICAL PERFORMANCE CHARACTERISTICS 60 50 AMPLITUDE (dBµV/m) 40 30 20 10 0 –10 –20 SPREAD SPECTRUM MODE FIXED FREQUENCY MODE –30 –40 0 3 6 9 12 15 18 FREQUENCY (MHz) 21 24 27 30 DC2407 F01 DC2407A DEMO BOARD (WITH EMI FILTER INSTALLED) 12V INPUT TO 5V OUTPUT1 AT 4A AND 3.3V OUTPUT2 AT 4A, fSW = 2MHz Figure 1. Conducted EMI Performance 50 AMPLITUDE (dBµV/m) VERTICAL POLARIZATION 45 PEAK DETECTOR 40 35 30 25 20 15 10 5 CLASS 5 PEAK LIMIT SPREAD SPECTRUM MODE FIXED FREQUENCY MODE 0 –5 0 100 200 300 400 500 600 FREQUENCY (MHz) 700 800 900 1000 DC2407 F02 DC2407A DEMO BOARD (WITH EMI FILTER INSTALLED) 12V INPUT TO 5V OUTPUT1 AT 4A AND 3.3V OUTPUT2 AT 4A, fSW = 2MHz Figure 2: Radiated EMI Performance (CISPR 25 Radiated Emission Test with Class 5 Peak Limits) 2 dc2407af DEMO MANUAL DC2407A QUICK START PROCEDURE Demonstration circuit 2407A is easy to set up to evaluate the performance of the LT8650S. Refer to Figure 3 and Figure 4 for proper measurement equipment setup and follow the procedure below. 1. With power off, connect the input power supply to VEMI and GND. 2. With power off, connect the loads to VOUT1 and GND and VOUT2 and GND. 3. Turn on the power at the input. 4. Carefully evaluate other design parameters as needed. Figure 3. Proper Measurement Equipment Setup VOUT GND Figure 4. Measure Output Ripple dc2407af 3 DEMO MANUAL DC2407A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 2 C1, C4 CAP., 10μF, X5R, 50V, 10%, 1206 MURATA, GRM31CR61H106KA12L 2 2 C9, C10 CAP., 4.7pF, C0G, 50V, ±0.25pF, 0603 MURATA, GRM1885C1H4R7CA01D 3 2 C11, C14 CAP., 4.7μF, X5R, 25V, 10%, 0603 MURATA, GRM188R61E475KE11D 4 4 C12, C13, C33, C38 CAP., 47μF, X6S, 10V, 10%, 1206 MURATA, GRM31CC81A476ME44L 5 2 C17, C18 CAP., 10nF, X7R, 25V, 10%, 0603 MURATA, GRM188R71E103KA01D 6 3 C19, C20, C32 CAP., 1μF, X5R, 50V, 10%, 0603 MURATA, GRM188R61H105KAALD 7 2 C28, C29 CAP., 1μF, X7S, 10V, 10%, 0402 MURATA, GCM155C71A105KE38D 8 2 L1, L2 INDUCTOR, 1.0μH, XFL5030 COILCRAFT, XFL5030-102ME 9 4 R1, R3, R5, R6 RES., 1M, 1/10W, 1%, 0603 VISHAY, CRCW06031M00FKEA 10 1 R7 RES., 316k, 1/10W, 1%, 0603 VISHAY, CRCW0603316KFKEA 11 1 R8 RES., 191k, 1/10W, 1%, 0603 VISHAY, CRCW0603191KFKEA 12 2 R11, R12 RES., 100k, 1/10W, 1%, 0603 VISHAY, CRCW0603100KFKEA 13 1 R13 RES., 15k, 1/10W, 1%, 0603 VISHAY, CRCW060315K0FKEA 14 2 R14, R15 RES., 0Ω, 1/10W, 0603 VISHAY, CRCW06030000Z0EA 15 1 U1 I.C. LT8650SEV, LGA LINEAR TECH., LT8650SEV#PBF SUN ELECT., 63CE22BS Additional Demo Board Circuit Components 1 1 C2 CAP., 22μF, ALUM, 63V 2 0 C5, C6, C30, C31 (OPT) CAP., OPTION, 0402 3 0 C7, C8, C15, C16, C26, C27 (OPT) CAP., OPTION, 0603 4 2 C21, C22 CAP., 10μF, X7R, 50V, 10%, 1210 MURATA, GRM32ER71H106KA12L 5 4 C34-C37 CAP., 0.1μF, X7R, 50V, 10%, 0402 MURATA, GCM155R71H104KE02D 6 1 FB1 CHIP BEAD Wurth Elektronik, 74279226101 7 1 L3 INDUCTOR, 0.22μH Wurth Elektronik, 744373240022 8 0 R2, R4, R9, R10 (OPT) RES, OPTION 0603 Hardware for Demo Board Only 1 18 E1-E18 TESTPOINT, TURRET, 0.094" PBF MILL-MAX, 2501-2-00-80-00-00-07-0 2 1 JP1 HEADER 3 PIN 0.079 SINGLE ROW Wurth Elektronik, 62000311121 3 1 JP2 HEADER 3 PIN 0.079 DOUBLE ROW Wurth Elektronik, 62000621121 4 2 xJP1, xJP2 SHUNT, 0.079" CENTER Wurth Elektronik, 60800213421 5 4 (STAND-OFF) STAND-OFF, NYLON 11.1mm Wurth Elektronik, 702934000 4 dc2407af 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 E4 E18 E16 E15 E13 E11 E9 E3 E6 E2 C20 1uF 50V C11 4.7uF 25V C34 C35 0.1uF 50V 0402 VCC OPT OPT C21 10uF 50V 1210 C22 10uF 50V 1210 100K R8 191K R6 1M C5 C30 OPT 0402 FB1 74279226101 R11 R10 VOUT1 C26 C16 C10 4.7pF OPT VOUT1 C12 C33 C28 1uF 47uF 10V 0402 1206 C4 10uF 50V 1206 L3 0.22uH C17 10nF VCC C7 OPT 5 1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. 4 U1 3 22uF 63V SUNCON 63CE22BS + C2 3 VIN2 VIN1 (Fsw = 2MHz) R13 15K TEMP CLKOUT PG1 SS1 VC1 FB1 SW1 SW1 BST1 EN1 VIN1 VIN1 LT8650SEV C19 1uF 13 17 14 29 27 28 22 23 24 11 4 5 C36 744373240022 C37 0.1uF 50V 0402 0 R15 1.0uH L1 R4 OPT R1 1M NOTE: UNLESS OTHERWISE SPECIFIED VEMI 5.4V - 42V VCC TEMP CLKOUT PG1 SS1 GND VOUT1 5V / 4A EN1 GND VIN1 4 VCC 25 RT 1 GND GND GND GND GND GND 38 37 36 35 34 33 BIAS PG2 SS2 VC2 FB2 SW2 SW2 BST2 EN2 VIN2 VIN2 GND GND 26 15 30 32 31 19 20 18 12 7 8 0 C18 10nF R14 1.0uH L2 JP1 1 BURST 6 5 2 4 2 VCC VOUT2 OPT OPT 100K C27 C15 R9 C29 1uF 0402 C1 10uF 50V 1206 OPT C9 4.7pF 3 JP2 1 VBIAS 3 R12 R7 316K R5 1M C6 C31 OPT 0402 2 OUT1 FCM W / SSM VOUT1 VCC C8 OPT R2 OPT R3 1M FCM W/O SSM OR SYNC 10 2 SYNC 16 2 5 C32 1uF VOUT2 C13 C38 C14 47uF 4.7uF 10V 25V 1206 VIN2 E1 E17 E14 E12 E10 E8 E7 E5 1 SYNC VBIAS PG2 SS2 GND VOUT2 3.3V / 4A EN2 GND 1 A B C D DEMO MANUAL DC2407A SCHEMATIC DIAGRAM dc2407af 5 DEMO MANUAL DC2407A 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 dc2407af LT 0917 • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 2017