DEMO MANUAL DC2279A LT3088EDD 800mA Single Resistor Rugged Linear Regulator DESCRIPTION DC2279A is a linear regulator evaluation board featuring LT®3088EDD, which is a 36VIN, 800mA, rugged single resistor programmable linear regulator. The demo circuit operates over an input range of 1.6V to 36V. The LT3088 has a maximum output current of 800mA. A key feature of the IC is the extended safe operation area (SOA). The IC also features paralleled capability for higher output current or heat spreading. This device allows one single resistor to program output voltage to any level between 0V and 34.5V if the load current is larger than 2mA. Built-in protection includes reverse battery protection, reverse current protection, internal current limit and thermal limit. DC2279A uses the LT3088EDD which is an 8-lead (3mm × 3mm) plastic DFN package with an exposed pad on the bottom-side of the IC for better thermal performance. These features make DC2279A an ideal circuit for surfacemount power supplies, rugged industrial power supplies, low output voltage supplies, a post regulator for switching supplies and intrinsic safety applications. Design files for this circuit board are available at http://www.linear.com/demo/DC2279A 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. BOARD PHOTO dc2279af 1 DEMO MANUAL DC2279A PERFORMANCE SUMMARY Specifications are at TA = 25°C VIN (V) CONDITIONS Shunt at 1.2V for JP1 IOUT (mA) MIN TYP VOUT (V) MAX* MIN TYP MAX 100 2.41 36.0 1.17 1.20 1.25 800 2.80 5.6 1.17 1.20 1.25 Shunt at 1.5V for JP1 100 2.71 36.0 1.46 1.50 1.56 800 3.10 6.0 1.46 1.50 1.56 Shunt at 1.8V for JP1 100 3.01 36.0 1.75 1.80 1.88 800 3.40 6.3 1.75 1.80 1.88 Shunt at 2.5V for JP1 100 3.71 36.0 2.43 2.50 2.60 800 4.10 7.0 2.43 2.50 2.60 100 4.51 36.0 3.20 3.30 3.44 800 4.90 7.8 3.20 3.30 3.44 100 6.21 36.0 4.85 5.00 5.20 800 6.60 9.5 4.85 5.00 5.20 Shunt at 3.3V for JP1 Shunt at 5.0V for JP1 *The maximum input voltage for 800mA load current is set by the 75°C temperature rise of LT3088 on the demo circuit. Higher input voltage can be reached if larger copper area or force-air cooling is applied. QUICK START PROCEDURE DC2279A is easy to set up to evaluate the performance of the LT3088. 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.Use JP1 to set the desired output voltage. 2.With power off, connect the input power supply to VIN and GND. 3.Turn on the power at the VIN. NOTE: Make sure that the VIN voltage does not exceed 36V. 4.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. 5.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. 2 dc2279af DEMO MANUAL DC2279A QUICK START PROCEDURE Figure 1. Test Procedure Setup Drawing for DC2279A + VOUT – COUT GND Figure 2. Measuring Input and Output Ripple dc2279af 3 DEMO MANUAL DC2279A THERMAL IMAGE An example thermal image shows the temperature distribution on the PC board. The test is done in still air at room temperature with 2.5W power dissipation in the LT3088 IC. This gives an IC case-to-ambient thermal resistance of θCA = 18°C/W on the demo circuit. The IC, at its highest point reaches 66°C, at 4.4VIN, 1.2VOUT, 800mA load current. Figure 3. Temperature Rise at 2.5W Dissipation (VIN = 4.4V, VOUT = 1.2V, IOUT = 800mA) PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER CAP, X7R, 1μF, 50V, 10% 0805 MURATA, GRM21BR71H105KA12L Required Circuit Components 1 1 C1 2 1 C2 CAP, X5R, 10μF, 50V, 10% 1206 MURATA, GRM31CR61H106KA12L 3 1 C3 CAP, C0G, 0.01μF, 50V, 5% 0603 MURATA, GRM1885C1H103JA01J 4 1 R1 RES., CHIP, 301k, 1/10W, 1% 0603 VISHAY, CRCW0603301KFKEA 5 1 R2 RES., CHIP, 560Ω, 1/4W, 5% 1206 VISHAY, CRCW1206560RJNEA 6 1 R3 RES., CHIP, 26.1k, 1/10W, 1% 0603 VISHAY, CRCW060326K1FKEA 7 1 R4 RES., CHIP, 33.2k, 1/10W, 1% 0603 VISHAY, CRCW060333K2FKEA 8 1 R5 RES., CHIP, 41.2k, 1/10W, 1% 0603 VISHAY, CRCW060341K2FKEA 9 1 R6 RES., CHIP, 60.4k, 1/10W, 1% 0603 VISHAY, CRCW060360K4FKEA 10 1 R7 RES., CHIP, 84.5k, 1/10W, 1% 0603 VISHAY, CRCW060384K5FKEA 11 1 R8 RES., CHIP, 150k, 1/10W, 1% 0603 VISHAY, CRCW0603150KFKEA 12 1 U1 IC., LT3088EDD DFN-8 (3 × 3) LINEAR TECH., LT3088EDD#PBF SUN SELECT., 50CE10BSS Additional Demo Board Circuit Components 13 1 C4 CAP., ALUM, 10µF, 50V 5 × 5.4mm 14 0 R9 (OPT) RES., 0603 Hardware: For Demo Board Only 4 15 4 E1, E2, E3, E4 TESTPOINT, TURRET, 0.094" PBF MILL-MAX, 2501-2-00-80-00-00-07-0 16 1 JP1 2 × 7, 0.079" DOUBLE ROW HEADER SULLINS, NRPN072PAEN-R 17 1 XJP1 SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G dc2279af DEMO MANUAL DC2279A SCHEMATIC DIAGRAM dc2279af 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. 5 DEMO MANUAL DC2279A 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 dc2279af 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