DEMO MANUAL DC2205A LT8495 SEPIC/Boost Converter with 2A, 70V Switch, 9µA Quiescent Current, POR and Watchdog Timer DESCRIPTION Demonstration circuit 2205A is a monolithic SEPIC converter featuring LT®8495. 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 LT8495 is a monolithic switching regulator with a power-on reset and watchdog timer. Quiescent current can be less than 9μA when operating. Dual supply pins (VIN and BIAS) allow the part to automatically operate from the most efficient supply. The switching regulation, watchdog timer and reset detection functions are controlled by the SWEN, WDE and RSTIN respectively. The reset and watchdog timeout periods are independently adjustable using external capacitors C5 and C6. The watchdog timer is enabled by default on the demo board, and it can be disabled by moving the JP1 to GND. PERFORMANCE SUMMARY SYMBOL PARAMETER VIN Input Supply Range 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 max load current with different input voltages of the demo board. The LT8495 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 2205A. The LT8495 is assembled in a 20-lead plastic TSSOP package. 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/DC2205A 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. Specifications are at TA = 25°C CONDITIONS MIN Output Voltage Switching Frequency RT = 169kΩ IOUT Max Output Current VIN = 12V EFE Efficiency at DC VIN = 12V, IOUT = 1A 2.5 80 2.0 60 VIN = 12V VOUT = 5V fSW = 450kHz 0 0.2 0.4 0.6 LOAD CURRENT (A) 0.8 1 DC2205A F01 Figure 1. LT8495 Efficiency 60 V 4.86 5.04 5.24 V 414 450 477 kHz A 80.2 90 70 UNITS 1 MAX LOAD CURRENT (A) EFFICIENCY (%) VOUT 40 MAX 3 fSW 50 TYP % 1.5 1.0 0.5 0 0 10 20 30 40 INPUT VOLTAGE (V) 50 60 DC2205A F02 Figure 2. LT8495 Max Load Current (Typical) vs Input Voltage dc2205afa 1 DEMO MANUAL DC2205A QUICK START PROCEDURE Demonstration circuit 2205A is easy to set up to evaluate the performance of the LT8495. Refer to Figure 3 for proper measurement equipment setup and follow the procedure below. 2.With power off, connect the input power supply to VIN and GND. Make sure that the input voltage does not exceed 60V. 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. 4.Turn on the power at the input. 1.Place JP1 on the RST position to enable the watchdog timer. It can be disabled by placing JP1 on the GND position. 3.With power off, connect loads from VOUT to GND. 5.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. 6.Once the proper output voltages are established, adjust the load within the operating ranges and observe the output voltage regulation, ripple voltage, efficiency and other parameters. Figure 3. Proper Measurement Equipment Setup 2 dc2205afa DEMO MANUAL DC2205A QUICK START PROCEDURE VOUT GND Figure 4. Measuring Input or Output Ripple dc2205afa 3 DEMO MANUAL DC2205A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Demo Board Circuit Components 1 1 C2 CAP., 2.2μF, X7R, 100V, 10%,1206 AVX, 12061C225KAT2A 2 2 C3, C4 CAP., 47μF, X5R, 10V, 1210 MURATA, GRM32ER61A476KE20L 3 1 C5 CAP., 4.7nF, X7R, 50V, 10%, 0603 AVX, 06035C472KAT2A 4 1 C6 CAP., 1nF, X7R, 25V, 10%, 0603 AVX, 06033C102KAT2A 5 2 C7, C9 CAP., 1μF 20% 25V X5R 0603 AVX, 06033D105MAT2A 6 1 C8 CAP., 2.2μF, X7R, 100V, 10%, 1210 AVX,12101C225KAT2A 7 1 C11 CAP., 4.7pF, C0G, 50V, ±.25pF, 0603 MURATA, GRM1885C1H4R7CA01D 8 1 D1 DIODE, SCHOTTKY, 2A, 100V, SMA ON SEMI., MBRA2H100T3G 9 1 L1 IND, 15μH, 20% VISHAY, IHCL4040DZER150M5A 10 2 R1, R10 RES., 1M, 1/10W, 1%, 0603 VISHAY, CRCW06031M00FKEA 11 1 R2 RES., 316k,1/10W, 1%, 0603 VISHAY, CRCW0603316KFKEA 12 2 R3, R4 RES., 100k, 1/10W, 1%, 0603 VISHAY, CRCW0603100KFKEA 13 1 R5 RES., 8.87k,1/10W, 1%, 0603 VISHAY, CRCW06038K87FKEA 14 1 R6 RES., 169k,1/10W, 1%, 0603 VISHAY, CRCW0603169KFKEA 15 1 R9 RES., 0Ω, 1/10W, 0603 VISHAY, CRCW06030000Z0EA 16 1 U1 I.C., LT8495EFE, TSSOP20FE LINEAR TECH., LT8495EFE#PBF Additional Demo Board Circuit Components 1 1 C1 CAP., ALUM., ELECT., 10μF, 63V SUN ELECTRONIC INDUSTRIES CORP., 63CE10BS 2 0 C10 CAP., OPTION, 0603 OPT 3 0 R11 RES., OPTION, 0603 OPT Hardware/Components (for Demo Board Only) 1 9 E1-E9 TP, TURRET, 0.094" MILL-MAX, 2501-2-00-80-00-00-07-0 2 1 JP1 CONN., HEADER, 1X3, 2mm WÜRTH, 62000311121 3 1 XJP1 SHUNT, 2mm WÜRTH, 60800213421 4 dc2205afa 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 VIN E9 E2 + C1 10uF 63V R10 1 Meg C2 2.2uF 100V 1206 R11 OPT C5 4.7nF C6 1nF C7 1uF 5 * THE MAX LOAD CURRENT IS REDUCED WHEN THE INPUT VOLTAGE IS LESS THAN 12V. PLEASE SEE DEMO MANUAL FOR DETAILS. RT SS CWDT CPOR SWEN VIN C8 2.2uF L1 15uH WDE WDI RST WDO FB FB RSTIN BIAS 4 3 13 16 7 15 3 2 11 1 100V 1210 1 CUSTOMER NOTICE (450kHz) R6 169k 10 8 6 5 12 18 U1 LT8495EFE IHCL-4040DZ-5A 2 3 4 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. GND RST JP1 WDE C10 OPT R9 0 SCALE = NONE DATE: N/A SIZE R3 100K 1% IC NO. DEMO CIRCUIT 2205A LT8495EFE Wednesday, February 25, 2015 2 C4 47uF 10V 1210 E8 E7 E6 E5 E4 C9 1uF WDE WDI RST WDO GND VOUT 5V / 1A * 02-25-15 DATE 1 SHEET 1 2 OF 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 E3 MOLLY Z. APPROVED 1 SEPIC CONVERTER WITH LOW IQ, POR AND WATCHDOG TIMER TECHNOLOGY R4 100K 1% PRODUCTION C11 4.7pF DESCRIPTION 2 REVISION HISTORY REV 2 MOLLY Z. TITLE: SCHEMATIC LT 1 2 3 R2 316K 1% R5 8.87K 1% R1 1 Meg 1% _ ECO D1 MBRA2H100T3G APPROVALS LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. 1. ALL RESISTORS AND CAPACITORS ARE IN OHMS, 0603. NOTES: UNLESS OTHERWISE SPECIFIED SWEN GND 3V - 60V * E1 4 NC 4 NC 9 SW 20 GND 14 GND 21 NC 17 NC 19 5 A B C D DEMO MANUAL DC2205A SCHEMATIC DIAGRAM dc2205afa 5 DEMO MANUAL DC2205A 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 dc2205afa Linear Technology Corporation LT 0515 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 2015