DEMO MANUAL DC2110A LT8631 100V, 1A Synchronous Micropower Step-Down Regulator Description Demonstration circuit 2110A is a monolithic step-down converter featuring LT®8631. The demo board is designed for 5V output from a 6.5V to 100V input at 400kHz switching frequency. The wide input range makes it suitable for regulating power from a wide variety of sources, including automotive, industrial systems and telecom supplies. The LT8631 is a compact, high efficiency synchronous monolithic step-down switching regulator. The power switch, compensation and other necessary circuits are inside of the LT8631 to minimize external components and simplify design. The LT8631 switching frequency can be programmed either via oscillator resistor or external clock over a 100kHz to 1MHz range. The SYNC pin on the demo board is grounded (JP1 at Burst Mode® position) by default for low ripple Burst Mode operation. To synchronize to an external clock, move JP1 to SYNC and apply the external clock to the SYNC turret. If the pulse-skipping operation is required, move JP1 to fixed frequency position. Figure 1 shows the efficiency of the circuit at 12V input at the Burst Mode selection. The demo board has an EMI filter installed. The EMI performance of the board (with EMI filter) is shown in Figure 2. The red line in Figure 2 is CISPR25 Class 5 peak limit. The figure shows that the circuit passes the test with a wide margin. To achieve EMI/EMC performance as shown 95 90 EFFICIENCY (%) 85 80 75 70 65 60 fSW = 400kHz VIN = 12V VOUT = 5V 55 50 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 LOAD CURRENT (A) 0.8 0.9 1 DC2110a F01 Figure 1. LT8631 Efficiency vs Load Current in Figure 2, the input EMI filter is required and the input voltage should be applied at VEMI turret pin, not VIN. The LT8631 data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this demo manual for demo circuit 2110A. The LT8631 is assembled in a 20-lead TSSOP packages. Proper board layout is essential for maximum thermal and electrical performance. See the data sheet sections for details. Design files for this circuit board are available at http://www.linear.com/demo/DC2110A 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. Performance Summary Specifications are at TA = 25°C SYMBOL PARAMETER CONDITIONS VIN Input Supply Range 6.5 100 V VOUT Output Voltage 4.88 5.04 5.2 V fSW Switching Frequency RT = 25.5kΩ 370 400 430 kHz IOUT Max Output Current VIN = 12V EFE Efficiency at DC VIN = 12V, IOUT = 1A 82.6 % VIN = 12V, IOUT = 0.4A 89.5 % MIN TYP 1 MAX UNITS A dc2110af 1 DEMO MANUAL DC2110A Quick Start Procedure Demonstration circuit 2110A is easy to set up to evaluate the performance of the LT8631. Refer to Figure 3 for proper measurement equipment setup and follow the procedure below: 4.Turn on the power at the input. 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 4 for the proper scope technique. NOTE. If there is no output, temporarily disconnect the load to make sure that the load is not set too high or is shorted. 1.Place JP1 on GND position. 2.With power off, connect the input power supply to VEMI and GND. If the EMI/EMC performance is not important, the input EMI filter can be bypassed by connecting the input power supply to VIN and GND. 3.With power off, connect loads from VOUT to GND. 5.Check for the proper output voltages (VOUT = 5V). 6.Once the proper output voltage is established, adjust the load within the operating ranges and observe the output voltage regulation, ripple voltage, efficiency and other parameters. 7.An external clock can be added to the SYNC terminal when SYNC function is used (JP1 on the SYNC position). Please ensure that the chosen RT sets the LT8631 switching frequency to 10% below the lowest SYNC frequency. See the data sheet Synchronization section for details. Detector: +Peak Polarity: Vertical Amplitude (dBuV/m) Am Amplitude (dBuV/m) 50 45 40 35 30 25 20 15 10 5 0 -5 Make sure that the input voltage does not exceed 100V. Data Class 5 Peak 0 100 200 Detector: +Peak Polarity: Horizontal 50 45 40 35 30 25 20 15 10 5 0 -5 0 100 200 300 400 500 600 Frequency (MHz) 700 800 900 1000 Data Class 5 Peak 300 400 500 600 Frequency (MHz) 700 800 900 1000 Figure 2. LT8631 Demo Circuit DC2110A EMI Performance in CISPR25 Radiated Emission Test (14V Input from VEMI Turret Pin, IOUT = 1A) dc2110af 2 DEMO MANUAL DC2110A Quick Start Procedure – POWER SUPPLY IIN A + – – + + V VIN + + IOUT A V VOUT – – + LOAD – Figure 3. Proper Measurement Equipment Setup VOUT GND Figure 4. Measurement Input or Output Ripple dc2110af 3 DEMO MANUAL DC2110A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C1 CAP, 0.1µF, X7R, 10V, 10% 0402 TDK, C1005X7R1A104K 2 1 C5 CAP, 2.2µF, X5R, 10V, 10% 0402 TDK, C1005X5R1A225K050BC 3 1 C6 CAP, 4.7pF, C0G, 50V, 0.25pF 0603 MURATA, GRM1885C1H4R7CA01D 4 1 C7 CAP, 47µF, X7R, 10V, 20% 1210 MURATA, GRM32ER71A476KE15L 5 1 C8 CAP, 0.1µF, X7R, 10V, 10% 0603 AVX, 0603ZC104KAT2A 6 1 C4 CAP, 1µF, X7R, 10V, 10% 0603 SAMSUNG, CL10B105KP8NNNC 7 1 L1 INDUCTOR, 22µH IHLP2525 VISHAY, IHLP2525CZER220M11 8 1 L2 INDUCTOR, 2.2µH COILCRAFT, XFL4020-222MEB 9 1 R1 RES, 51.1k, 1/10W, 1% 0603 VISHAY, CRCW060351K1FKEA 10 2 R2, R4 RES, 1M, 1/10W, 1% 0603 VISHAY, CRCW06031M00FKEA 11 1 R3 RES, 25.5k, 1/10W, 1% 0603 VISHAY, CRCW060325K5FKEA 12 1 R5 RES, CHIP, 191k, 1/10W, 1% 0603 VISHAY, CRCW0603191KFKEA 13 1 U1 IC, BUCK REG FE-20(16) CB LINEAR TECHNOLOGY, LT8631EFE#PBF SUN ELECTRONIC, 100CE10BS Additional Demo Board Circuit Components 1 1 C2 CAP, ALUM, 10µF, 100V 2 0 C11 (OPT) CAP, 0603 3 0 D1 (OPT) SCHOTTKY BARRIER REC, POWER-DI-123 Hardware: For Demo Board Only 1 10 E1 TO E10 TEST POINT, TURRET, 0.094" MTG.HOLE MILL-MAX, 2501-2-00-80-00-00-07-0 2 1 JP1 4 PIN 0.079 SINGLE ROW HEADER SULLIN, NRPN041PAEN-RC 3 1 XJP1 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G 4 0 R6 (OPT) RES, 0603 5 4 MH1 TO MH4 STAND-OFF, NYLON 0.50" KEYSTONE, 8833 (SNAP ON) dc2110af 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. 1 2 3 4 E9 E8 E10 E4 E3 E2 C9 2.2uF 100V 1210 L2 2.2uH R6 OPT R4 1M XFL4020-222ME C3 2.2uF 100V 1210 C10 2.2uF 100V 1210 100CE10BS C2 + 10uF 100V VIN VIN R3 25.5K (400kHz) B A 1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. B NOTE: UNLESS OTHERWISE SPECIFIED GND VEMI TR/SS EN/UV GND VIN 6.5V - 100V A C8 0.1uF 10 9 8 7 6 5 3 1 C11 0.1uF 100V 4 3 2 1 R5 191k 1% R2 1M 1% C5 2.2uF 10V 0402 C1 0.1uF 0402 10V C DATE: N/A SIZE C4 1uF 10V R1 51.1k SYNC GND VOUT 5V / 1A PG D Tuesday, July 07, 2015 E SHEET 1 OF 1 3 REV. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only E7 E6 E5 E1 E 100V 1A SYNCHRONOUS MICROPOWER BUCK REGULATOR IC NO. LT8631EFE DEMO CIRCUIT 2110A TECHNOLOGY C7 47uF 10V 1210 TITLE: SCHEMATIC C6 4.7pF D1 DFLS1100 OPT D L1 22uH IHLP2525CZER220M11 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. CUSTOMER NOTICE JP1 11 12 13 14 15 16 18 20 LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. SYNC BURST MODE FIXED FREQ 21 FB NC TR/SS NC VOUT RT NC IND INTVCC SYNC/MODE GND SW BST NC PG EN/UV VIN U1 LT8631EFE C 1 2 3 4 DEMO MANUAL DC2110A Schematic Diagram dc2110af 5 DEMO MANUAL DC2110A 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 dc2110af 6 Linear Technology Corporation LT 0915 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2015