DC1730A

DEMO MANUAL DC1730A LT3973 42V, 750mA Step-Down Regulator with 2.5µA Quiescent Current DESCRIPTION Demonstration circuit 1730A features the LT3973, a monolithic step-down switching regulator which consumes only 2.5μA quiescent current. The demo circuit is designed for a 5V, 750mA output from a 5.6V to 42V input. The wide input range of the LT3973 allows a variety of input sources including automotive batteries and 24V industrial supplies. In order to reduce the number of components and solution size, the catch diode and boost diode are integrated. The switching frequency is adjustable up to 2.2MHz. At light loads, the regulator operates in Burst Mode® to maintain high efficiency and low output ripple. The current mode control scheme creates fast transient response and good loop stability. During short circuit and PERFORMANCE SUMMARY PARAMETER overvoltage conditions, the catch diode current is limited to protect the part. Users can populate R7 and R8 on the EN/UVLO pin to provide a programmable undervoltage lockout. In addition, the shutdown feature can be utilized by placing jumper JP1 in the OFF position. The LT3973 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 working on or modifying the demo circuit 1730A. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. (TA = 25°C) CONDITIONS VALUE Minimum Input Voltage 5.6V Maximum Input Voltage 42V Output Voltage 5.04V±3% Maximum Output Current 750mA Typical Switching Frequency 600kHz VIN = 12V, IOUT = 750mA Typical Efficiency 84% 90 EFFICIENCY (%) 80 70 60 50 40 0 0.1 0.2 0.3 0.4 0.5 0.6 LOAD CURRENT (A) 0.7 0.8 dc1730af F01 Figure 1. DC1730A Efficiency: VIN = 12V, VOUT = 5V, 600kHz dc1730af 1 DEMO MANUAL DC1730A QUICK START PROCEDURE Demonstration circuit 1730A is easy to set up to evaluate the performance of the LT3973. Refer to Figure 2 for proper measurement equipment setup and follow the procedure below: 1. Place Jumper JP1 in the ON position. 2. With power off, connect the input power supply to VIN and GND. 3. With power off, connect load from VOUT to GND. 4. Turn on the power at the input. NOTE. Make sure that the input voltage does not exceed 42V. 5. Check for the proper output voltage. 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 loads within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. dc1730af 2 DEMO MANUAL DC1730A QUICK START PROCEDURE Figure 2. DC1730A Proper Measurement Equipment Setup GND VIN Figure 3. Measuring Input or Output Ripple dc1730af 3 DEMO MANUAL DC1730A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER REQUIRED CIRCUIT COMPONENTS 1 1 C1 CAP., X5R 22μF 6.3V 20% 1206 TAIYO YUDEN JMK316BJ226ML-T 2 1 C2 CAP., X5R 0.22μF 10V 20% 0402 AVX, 0402ZD224MAT2A 3 1 C3 CAP., X7R 2.2μF 50V 10% 1206 MURATA, GRM31CR71H225KA88L 4 1 C5 CAP., NPO, 10pF, 25V, 10%, 0402 AVX, 04023A100KAT2A 5 1 L1 IND, 15μH COOPER/COILTRONICS, MPI4040R3-150-R 6 1 R1 RES., CHIP, 1.00M, 1/16W, 1%, 0402 NIC, NRC04F1004TRF 7 1 R2 RES., CHIP, 316k, 1/16W, 1%, 0402 NIC, NRC04F3163TRF 8 1 R5 RES., CHIP, 215k, 1/16W, 1%, 0402 NIC, NRC04F2153TRF 9 1 R9 RES., CHIP, 200k, 1/16W, 5%, 0402 NIC, NRC04J204TRF 10 1 U1 I.C., Buck Reg. MSE10 LINEAR TECH., LT3973EMSE ADDITIONAL DEMO BOARD CIRCUIT COMPONENTS 1 1 C4 CAP., ALUMINUM EL. 10μF, 50V 2 0 R7-R8 RES., 0402 SUN ELECT, 50CE10BSS HARDWARE FOR DEMO BOARD ONLY 1 6 E1-E6 TURRET, 0.094" MILL-MAX, 2501-2-00-80-00-00-07-0 2 3 1 JP1 JMP, 1X3-079 WÜRTH, 62000311121 1 SHUNT SHUNT, 2mm Ctrs. WÜRTH, 60800213421 dc1730af 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. A B C E5 E6 OFF ON SUNCON 50CE10BSS + C4 10uF 50V VIN JP1 1 2 3 C3 2.2uF 50V 1206 R8 OPT R7 OPT 5 1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE IN MICROFARADS, 0402. NOTES: UNLESS OTHERWISE SPECIFIED EN/UVLO PG GND E4 VIN E3 5.6V - 42V GND OUT EN/UVLO PG VIN CUSTOMER NOTICE R9 200K 5 2 3 9 4 RT FB BD BOOST SW U1 LT3973EMSE 3 4 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. L1 15uH R5 215k 1% (600kHz) SCALE = NONE JAINO P. KIM T. _ ECO 2 C5 10pF C1 22uF 6.3V 1206 VOUT E2 E1 JAINO P. DATE 09-06-11 GND VOUT 5V / 750mA APPROVED 1 DATE: N/A SIZE IC NO. DEMO CIRCUIT 1730A 2 09/06/2011, 10:10 AM LT3973EMSE 1 SHEET 1 OF 1 2 REV. 42V, 750mA, MICROPOWER BUCK REGULATOR 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only PRODUCTION DESCRIPTION REVISION HISTORY TECHNOLOGY R2 316k 1% R1 1.00M 1% REV 2 TITLE: SCHEMATIC C2 0.22uF APPROVALS 10 1 8 7 6 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. 4 GND 11 D 5 A B C D DEMO MANUAL DC1730A SCHEMATIC DIAGRAM dc1730af 5 DEMO MANUAL DC1730A 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 dc1730af 6 Linear Technology Corporation LT 0911 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2011