DEMO MANUAL DC1865A LT3055 500mA, Linear Regulator with Precision Current Limit and Diagnostics Description Demonstration circuit 1865A is an adjustable 500mA linear regulator featuring LT®3055. LT3055 is a micropower, low noise and low dropout voltage linear regulator. The device supplies 500mA of output current with a dropout voltage of 350mV. A 10nF bypass capacitor reduces output noise to 25µVRMS in a 10Hz to 100kHz bandwidth and soft-starts the reference. The LT3055’s ±45V input voltage rating combined with its precision current limit and diagnostic functions make the IC an ideal choice for robust, high reliability applications. tion in the data sheet for a detailed calculation. Logic fault pins assert low if the LT3055 is in current limit (FAULT2), operating below its minimum output current (FAULT1) or is in thermal limit (both FAULT1 and FAULT2). The die temperature is indicated by the TEMP pin. LT3055 current limit can be programmed by a single resistor, accurate to ±10% over a wide input voltage and temperature range. Another resistor programs the LT3055’s minimum output current monitor, useful for detecting open-circuit conditions. The internal current limit should be considered when the input-to-output differential is high. The current monitor function sources a current equal to 1/500th of output current. See the Operation sec- The LT3055 data sheet gives a complete description of the device, operation and application information. The data sheet must be read in conjunction with this quick start guide for DC1865. Performance Summary LT3055 optimizes stability and transient response with a low ESR ceramic capacitor, requiring a minimum of 3.3µF. The LT3055 is available in the thermally-enhanced 16-lead 4mm × 3mm DFN and MSOP packages. Design files for this circuit board are available at http://www.linear.com/demo/DC1865A 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. Specifications are at TA = 25°C PARAMETER CONDITIONS VALUE Minimum Input Voltage (Max) VOUT = 5V, IOUT = 500mA 5.6V Maximum Input Voltage VOUT = 5V 45V Output Voltage VOUT Header in JP1 Header in JP2 Header in JP3 Header in JP4 Header in JP5 Header in JP6 Maximum Output Current (Typ) VIN = 12V, VOUT = 5V, R10 = 604Ω 500mA Minimum Output Current (Typ) VIN = 12V, VOUT = 5V, R9 = 121kΩ 10mA IMON Voltage (to µP ADC) (Typ) VIN = 12V, VOUT = 5V, R8 = 1k, IOUT = 500mA Temp voltage (Typ) VIN = 12V, VOUT = 5V 1.20V ±3% 1.50V ±3% 1.80V ±3% 2.50V ±3% 3.32V ±3% 4.99V ±3% 1V 0.25V dc1865af 1 DEMO MANUAL DC1865A Quick Start Procedure DC1865A is easy to set up to evaluate the performance of the LT3055. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: NOTE: Make sure that the input voltage does not exceed 45V. NOTE: The shutdown jumper JP8 shunt is required to be placed in the OFF or ON position for proper operation. NOTE: Place the output voltage selection jumper JP1-JP7 at the desired position. NOTE: Do not hot-plug the input voltage terminal VIN. The absolute maximum voltage on VIN is 50V and hot-plugging a power supply through wire leads to the demonstration circuit can cause the voltage on the extremely low-ESR ceramic input capacitor to ring to twice its DC value. In order to protect the IC, a higher ESR Aluminum Electrolytic capacitor is placed at the input terminals. This may protect against some, but not all, input transients due to hot-plugging with a power supply. See Application Note 88 for more details. 1. After all connections are made, turn on input power and verify that the output voltage according to the output voltage selection jumper (JP1-JP7). If the output voltage is different from the above values, use the USER option and install R7. Select R7 according to the following equation: R7 = (VOUT/0.6 – 1) • 60.4k NOTE: If the output voltage is too low, temporarily disconnect the load to make sure that the load is not set too high. 2. Once the proper output voltage is established, adjust the load within the operating range and observe the output voltage regulation, FAULT1, FAULT2, PWRGD and other parameters. NOTE: Connect the power supply (with power off), load, and meters as shown in Figure 1. 2 dc1865af DEMO MANUAL DC1865A Quick Start Procedure Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple dc1865af 3 DEMO MANUAL DC1865A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 2 C1, C8 Cap., X7R, 0.01µF, 16V, 10% 0603 AVX, 0603YC103KAT2A 2 2 C2, C3 Cap., X5R, 0.1µF, 16V, 20% 0402 AVX, 0402YD104MAT2A 3 1 C4 Cap., X7R, 22nF, 16V, 10% 0402 AVX, 0402YC223KAT2A 4 2 C5, C6 Cap., X7R, 10µF, 50V, 10% 1210 TAIYO YUDEN, UMK325AB7106KM-T 5 1 C9 Cap., X7R, 100pF, 16V, 10% 0402 AVX, 0402YC101KAT2A 6 2 R1, R12 Res., Chip, 60.4k, 0.06W, 1% 0402 VISHAY, CRCW040260K4FKED 7 1 R2 Res., Chip, 90.9k, 0.06W, 1% 0402 VISHAY, CRCW040290K9FKED 8 1 R3 Res., Chip, 121k, 0.06W, 1% 0402 VISHAY, CRCW0402121KFKED 9 1 R4 Res., Chip, 191k, 0.06W, 1% 0402 VISHAY, CRCW0402191KFKED 10 1 R5 Res., Chip, 274k, 0.06W, 1% 0402 VISHAY, CRCW0402274KFKED 11 1 R6 Res., Chip, 442k, 0.06W, 1% 0402 VISHAY, CRCW0402442KFKED 12 1 R8 Res., Chip, 1.00k, 0.1W, 1% 0603 VISHAY, CRCW06031K00FKEA 13 1 R9 Res., Chip, 121k, 0.1W, 1% 0603 VISHAY, CRCW0603121KFKEA 14 1 R10 Res., Chip, 604Ω, 0.1W, 1% 0603 VISHAY, CRCW0603604RFKEA 15 3 R11, R13, R14 Res., Chip, 499k, 0.1W, 1% 0603 VISHAY, CRCW0603499KFKEA 16 1 U1 I.C., Volt. Reg., DFN-16 (4×3) LINEAR TECH., LT3055EDE#PBF SUN SELECT, 50CE22BSS Additional Demo Board Circuit Components 1 1 CIN Cap., Alum., 22µF, 50V, 6.3mm × 5.4mm 2 0 C7 (OPT) Cap., D Case 3 0 R7 (OPT) Res., 0603 Hardware-For Demo Board Only 1 9 E1-E9 Turret, Testpoint 0.094" MILL-MAX 2501-2-00-80-00-00-07-0 2 7 JP1-JP7 Headers, 2 Pins 2mm Ctrs. SAMTEC, TMM-102-02-L-S 3 1 JP8 Headers, Single Row 3 Pins 2mm Ctrs. SAMTEC, TMM-103-02-L-S 4 2 XJP6, XJP8 Shunt, 2mm Ctrs. SAMTEC, 2SN-BK-G 4 dc1865af GND VIN 2.2V - 45V FAULT1 FAULT2 PWRGD E2 E1 JP8 SHDN OFF ON E5 E9 E8 3 2 1 + CIN 22uF 50V R11 499K 1% 0603 R14 499K 1% 0603 1210 1 2 3 6 5 4 C5 10uF 50V C3 0.1uF 9 11 IN IN SHDN PWRGD FAULT2 FAULT1 IMIN REF/BYP NOTE: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS ARE 0402. ALL CAPACITORS ARE 0402. R13 499K 1% 0603 R9 121k 1% 0603 C1 0.01uF 0603 17 GND U1 LT3055EDE OUT OUT ADJ GND GND IMAX TEMP IMON C8 0.01uF 16 0603 15 14 12 13 10 7 8 1210 C6 10uF 50V C4 22nF R1 60.4K 1% JP1 1.2V R12 60.4K 1% R10 604 1% 0603 R2 90.9K 1% JP2 1.5V R3 121K 1% JP3 1.8V C9 0.1nF C2 0.1uF R4 191K 1% JP4 2.5V R8 1.00K 1% 0603 R5 274K 1% 3.3V JP5 R6 442K 1% JP6 5V C7 OPT "D" Case R7 OPT 0603 + E4 E3 USER SELECT JP7 E7 E6 GND VOUT 500mA TEMP IMON DEMO MANUAL DC1865A Schematic Diagram dc1865af 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 DC1865A 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 dc1865af Linear Technology Corporation LT 0613 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2013