LT8495 LINER

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Technical content

DESCRIPTION

LT8495 SEPIC/Boost Converter with 2A, 70V Switch, 9µA Quiescent Current, POR and Watchdog Timer Demonstration circuit 2205A is a monolithic SEPIC con- verter 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 volt- age. 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 detec- tion 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. L, L T , L TC, L TM, 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. PERFORMANCE SUMMARY 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 Specifications are at TA = 25°C SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VIN Input Supply Range 3 60 V VOUT Output Voltage 4.86 5.04 5.24 V fSW Switching Frequency RT = 169kΩ 414 450 477 kHz IOUT Max Output Current VIN = 12V 1 A EFE Efficiency at DC VIN = 12V, IOUT = 1A 80.2 % V IN = 12V V OUT = 5V f SW = 450kHz LOAD CURRENT (A) 0.2 0.4 0.6 0.8 EFFICIENCY (%) DC2205A F01 INPUT VOL TAGE (V) 0.5 1.0 1.5 2.0 2.5 MAX LOAD CURRENT (A) DC2205A F02 Figure 1. LT8495 Efficiency Figure 2. LT8495 Max Load Current (Typical) vs Input Voltage

  1. Place JP1 on the RST position to enable the watchdog
  2. With power off, connect the input power supply to VIN
  3. With power off, connect loads from VOUT to GND.
  4. Turn on the power at the input.
  5. Check for the proper output voltages (VOUT = 5V).

to make sure that the load is not set too high or is shorted.

  1. Once the proper output voltages are established, adjust

Figure 3. Proper Measurement Equipment Setup

Figure 4. Measuring Input or Output Ripple

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

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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. SCHEMATIC DIAGRAM D D C C B B A A NOTES: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS AND CAPACITORS ARE IN OHMS, 0603. (450kHz) 100V IHCL-4040DZ-5A * THE MAX LOAD CURRENT IS REDUCED WHEN THE INPUT VOLTAGE IS LESS THAN 12V. PLEASE SEE DEMO MANUAL FOR DETAILS. RST GND WDE SIZE DATE: IC NO. REV. SHEET OF TITLE: APPROVALS PCB DES. APP ENG. TECHNOLOGY Fax: (408)434-0507 Milpitas, CA 95035 Phone: (408)432-1900 1630 McCarthy Blvd. LTC Confidential-For Customer Use Only CUSTOMER NOTICE 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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SCHEMATIC SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE www.linear.com 2LT8495EFE Wednesday, February 25, 2015 1 1 LT MOLLY Z. N/A DEMO CIRCUIT 2205A POR AND WATCHDOG TIMER SEPIC CONVERTER WITH LOW IQ, SIZE DATE: IC NO. REV. SHEET OF TITLE: APPROVALS PCB DES. APP ENG. TECHNOLOGY Fax: (408)434-0507 Milpitas, CA 95035 Phone: (408)432-1900 1630 McCarthy Blvd. LTC Confidential-For Customer Use Only CUSTOMER NOTICE 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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SCHEMATIC SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE www.linear.com 2LT8495EFE Wednesday, February 25, 2015 1 1 LT MOLLY Z. N/A DEMO CIRCUIT 2205A POR AND WATCHDOG TIMER SEPIC CONVERTER WITH LOW IQ, SIZE DATE: IC NO. REV. SHEET OF TITLE: APPROVALS PCB DES. APP ENG. TECHNOLOGY Fax: (408)434-0507 Milpitas, CA 95035 Phone: (408)432-1900 1630 McCarthy Blvd. LTC Confidential-For Customer Use Only CUSTOMER NOTICE 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. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SCHEMATIC SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE www.linear.com 2LT8495EFE Wednesday, February 25, 2015 1 1 LT MOLLY Z. N/A DEMO CIRCUIT 2205A POR AND WATCHDOG TIMER SEPIC CONVERTER WITH LOW IQ,

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV MOLLY Z.PRODUCTION2 02-25-15_ DESCRIPTION DATEAPPROVEDECO REV MOLLY Z.PRODUCTION2 02-25-15_ DESCRIPTION DATEAPPROVEDECO REV MOLLY Z.PRODUCTION2 02-25-15_ 47uF 10V 1210 47uF 10V 1210 8.87K 8.87K R11 OPT R11 OPT JP1JP1 VIN 3V - 60V * VIN 3V - 60V * LT8495EFE LT8495EFE SS8 RT10 RSTIN 11SWEN12 WDE 13 WDO 15 VIN18 WDI 16 GND14 SW20 BIAS 1 FB 3CPOR5 CWDT6 RST 7 NC 17 FB 2 NC 4 NC 9 NC 19 GND21 2.2uF 100V 1206 2.2uF 100V 1206 15uH 15uH 316K 316K SWEN SWEN 4.7nF 4.7nF 100K 100K 169k 169k WDI WDI GND GND

1 Meg

2.2uF 1210 2.2uF 1210 4.7pF C11 4.7pF C11 WDE WDE GND GND RST RST MBRA2H100T3G MBRA2H100T3GC10 OPT C10 OPT 100K 100K 1uF 1uF WDO WDO 47uF 10V 1210 47uF 10V 1210 1uF 1uF 1nF 1nF R10 5V / 1A *E3 VOUT 5V / 1A * + C1 10uF 63V + C1 10uF 63V

DEMO MANUAL DC2205A Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear .com  LINEAR TECHNOLOGY CORPORATION 2015 LT 0515 REV A • PRINTED IN USA 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