DEMO MANUAL DC2242A LT8494 SEPIC/Boost DC/DC Converter with 2A, 70V Switch, and 7µA Quiescent Current Description Demonstration circuit 2242A is a monolithic SEPIC converter featuring LT®8494. The demo board is designed for 5V output from a 3V to 60V input at 450kHz switching frequency. The max output current is 1A when the input voltage is above 12V, and is reduced with lower input voltage. The quiescent current of LT8494 is less than 7μA when operating. Dual supply pins (VIN and BIAS) allow the part to automatically operate from the most efficient supply. Low ripple Burst Mode® operation increases the efficiency at the light load while keeping the output ripple below 10mV. Figure 1 shows the demo board efficiency at 12V input voltage. Figure 2 shows the maximum load current with different input voltages of the demo board. The LT8494 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 DC2242A. The LT8494 is assembled in 20-lead QFN and 20-lead plastic 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/DC2242A 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. 90 MAXIMUM LOAD CURRENT (A) 2.5 EFFICIENCY (%) 80 70 60 50 40 VIN = 12V VOUT = 5V fSW = 450kHz 0 0.2 0.6 0.8 0.4 LOAD CURRENT (A) 2.0 1.5 1.0 0.5 0 1 0 10 30 40 20 INPUT VOLTAGE (V) DC2242A F01 60 DC2242A F01 Figure 1. LT8494 Efficiency Performance Summary 50 Figure 2. LT8494 Maximum Load Current (Typical) vs Input Voltage Specifications are at TA = 25°C SYMBOL PARAMETER VIN Input Supply Range CONDITIONS VOUT Output Voltage fSW Switching Frequency RT = 169kΩ IOUT Max Output Current VIN = 12V EFE Efficiency at DC VIN = 12V, IOUT = 1A MIN TYP 3 MAX 60 UNITS V 4.86 5.04 5.24 V 414 450 477 kHz 1 A 80.3 % dc2242af 1 DEMO MANUAL DC2242A Quick Start Procedure DC2242A is easy to set up to evaluate the performance of the LT8494. Refer to Figure 3 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 4 for the proper scope technique. 1.With power off, connect the input power supply to VIN and GND. Make sure that the input voltage does not exceed 60V. 2 2.With power off, connect loads from VOUT to GND. 3.Turn on the power at the input. 4.Check for the proper output voltages (VOUT = 5V). NOTE: If there is no output, temporarily disconnect the load to make sure that the load is not set too high or is shorted. 5.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. dc2242af DEMO MANUAL DC2242A Quick Start Procedure Figure 3. Proper Measurement Equipment Setup VOUT GND Figure 4. Measuring Input or Output Ripple dc2242af 3 DEMO MANUAL DC2242A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 2 C2, C8 CAP., X7R, 2.2µF, 100V, 10%, 1210 MURATA, GRM32ER72A225KA35L 2 2 C3, C4 CAP., X7R, 47µF, 10V, 10%, 1210 MURATA, GRM32ER71A476KE15L 3 2 C5, C7 CAP., X7R, 1µF, 10V, 10%, 0603 MURATA, GRM188R71A105KA61D 4 1 C6 CAP., NP0, 4.7pF, 50V, ±0.25pF, 0603 MURATA, GRM1885C1H4R7CA01D 5 1 D1 DIODE, SCHOTTKY 100V, 2A, SMA ON SEMI., MBRA2H100T3G 6 1 L1 INDUCTOR, 15µH VISHAY, IHCL4040DZER150M5A 7 2 R1, R10 RES., CHIP, 1M, 1/10W, 0603 VISHAY, CRCW06031M00FKEA 8 1 R2 RES., CHIP, 316K, 1/10W, 1%, 0603 VISHAY, CRCW0603316KFKEA 9 1 R4 RES., CHIP, 100k, 1/10W, 1%, 0603 VISHAY, CRCW0603100KFKEA 10 1 R6 RES., CHIP, 169k, 1/10W, 1%, 0603 VISHAY, CRCW0603169KFKEA 11 1 R9 RES., CHIP, 0, 1/10W, 0603 VISHAY, CRCW06030000Z0EA 12 1 U1 I.C., , LT8494, TSSOP-20-4.4mm LINEAR TECH., LT8494EFE#PBF Additional Demo Board Circuit Components 1 1 C1 CAP., ALUM, 10µF, 63V, 20% SUN ELECTRONIC, 63CE10BS 2 0 C10 (OPT) CAP., OPTION, 0603 OPT 3 0 R11 (OPT) RES., OPTION, 0603 OPT TESTPOINT, TURRET, .094" PBF MILL-MAX, 2501-2-00-80-00-00-07-0 Hardware: For Demo Board Only 1 4 6 E1-E6 dc2242af 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 C1 10uF 63V 63CE10BS + C2 2.2uF 100V 1210 R11 OPT R10 1M 5 1. ALL RESISTORS ARE IN OHMS, 0603. ALL CAPACITORS ARE IN MICROFARADS, 0603. 4 NOTES: UNLESS OTHERWISE SPECIFIED INPUT VOLTAGE IS LESS THAN 12V. PLEASE SEE DEMO MANUAL FOR DETAILS. E6 E2 E1 * THE MAX LOAD CURRENT IS REDUCED WHEN THE SWEN GND VIN 3V - 60V * 4 C7 1uF RT SS NC NC SWEN VIN NC PG NC FB FB NC BIAS 3 R9 0 C10 OPT 3 DATE: N/A SIZE 2 C6 4.7pF R4 100K 1% TECHNOLOGY R2 316K 1% C4 47uF 10V 1210 E5 E4 C5 1uF 10V 0603 E3 PG GND VOUT 5V / 1A * LT8494EFE DEMO CIRCUIT 2242A 2 Tuesday, May 05, 2015 IC NO. 1 SHEET 1 OF 1 1 REV. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only C3 47uF 10V 1210 1 SEPIC CONVERTER WITH LOW IQ SCHEMATIC R1 1M 1% D1 MBRA2H100T3G THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. CUSTOMER NOTICE 13 7 15 3 2 11 1 1210 C8 2.2uF 100V 1 L1 15uH IHCL4040DZ-5A 2 4 3 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 TITLE: CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. R6 169K (450kHz) 10 8 6 5 12 18 U1 LT8494EFE NC 4 NC 9 20 GND 14 SW GND 16 GND 21 NC 17 NC 19 5 A B C D DEMO MANUAL DC2242A Schematic Diagram dc2242af 5 DEMO MANUAL DC2242A 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 dc2242af Linear Technology Corporation LT 0715 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2015