DEMONSTRATION CIRCUIT 1728A QUICK START GUIDE LT3015 1.5A, Low Noise, Negative Linear Regulator with Precision Current Limit DESCRIPTION Demonstration circuit 1728A is an adjustable 1.5A negative linear regulator featuring the LT3015. This device supplies up to 1.5A of output current at a typical dropout voltage of 300mV. Operating quiescent current is typically 1.1mA and drops to < 1μA in shutdown. Quiescent current is also well controlled in dropout. In addition to fast transient response, the LT3015 exhibits very low output noise, making it ideal for noise-sensitive applications. A key feature of the LT3015 is the capability to supply a wide output voltage range. The DC1728A can be set to –1.22V, –2.5V, –5.0V, –12.0V, –15.0V, as well as a user select option. In addition, the DC1728A is capable of delivering up to –1.5A output current, and can be used as a high current negative linear regulator, post regulator for switching supply, variable voltage supply or low output voltage power supply. PERFORMANCE SUMMARY Internal protection circuitry includes reverse output protection, precision current limit with foldback and thermal limit with hysteresis. The LT3015 is available as an adjustable device with a –1.22V reference voltage. Packages include the 5-lead TO-220 and DD-Pak, a thermally enhanced 12-lead MSOP and the low profile 8-lead 0.75mm × 3mm × 3mm DFN. The LT3015 datasheet gives a complete description of the device, operation and application information. The datasheet should be read in conjunction with this quick start guide for working on or modifying the demo circuit 1728A. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, 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) SYMBOL PARAMETER CONDITIONS MIN VIN Input Supply Range VOUT = –1.22V, IOUT1 = –1mA –1.8 TYP MAX UNITS –30 V VOUT Output Voltage Shunt at 1, 2 for JP2 –1.183 –1.22 –1.257 V VOUT Output Voltage Shunt at 3, 4 for JP2 –2.425 –2.5 –2.575 V VOUT Output Voltage Shunt at 5, 6 for JP2 –4.85 –5.0 –5.15 V VOUT Output Voltage Shunt at 7, 8 for JP2 –11.64 –12.0 –12.36 V VOUT Output Voltage Shunt at 9, 10 for JP2 –14.55 –15.0 –15.45 V dc1728af 1 DEMONSTRATION CIRCUIT 1728A QUICK START GUIDE QUICK START PROCEDURE Demonstration circuit 1728A is easy to set up to evaluate the performance of the LT3015. Refer to Figure 1 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 terminals of the input or output capacitors. See Figure 2 for proper scope probe technique. 1. Place JP1 on the ON position. NOTE. Put JP1 = 1-2 for ON, JP1 = 1-4 for OFF, or JP1 = 1-3 for User Select. 2. Use JP2 to set the desired output voltage. 3. With power off, connect the input power supply to VIN and GND. 4. Turn on the power at the VIN. NOTE. Make sure that the VIN voltage does not exceed –30V. 5. Check for the proper output voltages. 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, efficiency and other parameters. NOTE. Make sure that the power dissipation is limited below the thermal limit. Figure 1. DC1728A Proper Equipment Setup dc1728af 2 DEMONSTRATION CIRCUIT 1728A QUICK START GUIDE QUICK START PROCEDURE Thermal Image GND VIN An example thermal image (Figure 3) shows the temperature distribution on the board. The test is done in still air at room temperature with 1.96W power dissipation in the LT3015. This gives the IC case-to-ambient thermal resistance θJA = 23°C/W on the demo board. Figure 2. Measuring Input or Output Ripple Figure 3. Temperature Rise at 1.96W Dissipation dc1728af 3 DEMONSTRATION CIRCUIT 1728A QUICK START GUIDE PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 CIN CAP., X7R, 10μF 50V, 10%, 1210 MURATA, GRM32ER71H106K 2 1 COUT CAP., X7R, 10μF 25V, 10%, 1206 MURATA, GRM31CR71E106KA12L 3 1 R1 RES., CHIP, 3.48k, 1/16W, 1% 0402 VISHAY, CRCW04023K48FKED 4 2 R2, RSD RES., CHIP, 0Ω, 0402 VISHAY, CRCW04020000Z0ED 5 1 R3 RES., CHIP, 3.65k, 1/16W, 1% 0402 VISHAY, CRCW04023K65FKED 6 1 R4 RES., CHIP, 11.0k, 1/16W, 1% 0402 VISHAY, CRCW040211K0FKED 7 1 R5 RES., CHIP, 30.9k, 1/16W, 1% 0402 VISHAY, CRCW040230K9FKED 8 1 R6 RES., CHIP, 39.2k, 1/16W, 1% 0402 VISHAY, CRCW040239K2FKED 9 1 R9 RES., CHIP, 100k, 1/16W, 1% 0402 VISHAY, CRCW0402100KFKED U1 I.C., LT3015EDD, DFN8DD LINEAR TECH., LT3015EDD Additional Demo Board Circuit Components 1 1 C1 CAP., ALUM., 10μF 50V, CE-BSS 2 0 C2 CAP., 7343 3 0 R7, R8 RES., CHIP, 0402 SUNCON, 50CE10BSS Hardware-For Demo Board Only 1 5 E1-E5 TP, TURRET, 0.094" MILL-MAX, 2501-2-00-80-00-00-07-0 2 1 JP1 JMP, 4 PINS, 0.079" SAMTEC, ASP-157349-01 3 1 JP2 JMP, 2 × 6, 0.079" SAMTEC, TMM-106-02-L-D 4 2 XJP1, XJP2 SHUNT, .079" CENTER SAMTEC, 2SN-BK-G dc1728af 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 CIN 10uF 50V 1210 3 USER SELECT JP1 R8 OPT 2 1 ON 4 OFF RSD 0 R9 100k 5 2. INSTALL SHUNTS AS SHOWN. 1. ALL RESISTORS ARE IN OHMS, 0402. ALL CAPACITORS ARE IN MICROFARADS. 3 2 1 SHDN IN IN ADJ OUT OUT 6 7 8 4 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. R2 0 SCALE = NONE EDWIN L. KT APPROVALS R1 3.48k U1 LT3015EDD 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 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. CUSTOMER NOTICE CAPACITOR C1 IS AN OPTIONAL PART. IT WAS INSERTED ON THE DC1728A TO DAMPEN THE (POSSIBLE) RINGING VOLTAGE DUE TO THE USE OF LONG INPUT LEADS. ON A NORMAL, TYPICAL PCB, WITH SHORT TRACES, THE CAPACITOR IS NOT NEEDED. SEE APPLICATION NOTE AN88 FOR MORE DETAILS. E4 SUNCON 50CE10BSS 10uF 50V *C1 NOTES: UNLESS OTHERWISE SPECIFIED * SHDN E2 VIN VIN -1.9V TO -30V E5 GND + D 9 IN GND 4 GND 5 1 REV R4 11.0k DATE: N/A SIZE R6 39.2k C2 OPT 7343 E3 E1 GND VOUT -1.5A MAX EDWIN L. VOUT DATE 04-20-11 APPROVED 1 IC NO. 2 Wednesday, April 20, 2011 LT3015EDD DEMO CIRCUIT 1728A 1 SHEET 1 1.5A, LOW NOISE, NEGATIVE REGULATOR WITH PRECISION CURRENT LIMIT 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 R7 OPT COUT 10uF 25V 1206 PRODUCTION DESCRIPTION REVISION HISTORY TECHNOLOGY R5 30.9k JP2 HD2X6-079 TITLE: SCHEMATIC R3 3.65k _ ECO 2 -1.22V -2.5V -5.0V -12.0V -15.0V USER SELECT 2 4 6 8 10 12 1 3 5 7 9 11 4 + 5 A B C D DEMONSTRATION CIRCUIT 1728A QUICK START GUIDE SCHEMATIC DIAGRAM dc1728af 5 DEMONSTRATION CIRCUIT 1728A QUICK START GUIDE 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 dc1728af 6 Linear Technology Corporation LT 0611 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2011