DEMO MANUAL DC1956A LT3905 Boost DC/DC Converter with APD Current Monitor Description The LT3905 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 the DC1956A. Design files for this circuit board are available at http://www.linear.com/demo/DC1956A 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. For measuring fast transient response, use the installed Fast Monitor Response Circuit on the bottom of the demo board and install 0Ω resistors at R14 and R20. Also, remove R11 and any other capacitances or probes across the APD node. The transient response should be measured at the TIA turret. For further information, read the APD Current Monitor Transient Response section in the data sheet. The internal LOS_MON comparator hysteresis is 20mV on the rising edge of the LOS_MON voltage. For additional hysteresis, use R6, R7, R15, and R21 as stated in the Loss of Signal Hysteresis section in the data sheet. 100 VAPD = 50V 80 INPUT CURRENT (mA) Demonstration circuit 1956A features the LT®3905, a boost DC/DC Converter with APD current monitor that comes in a 3mm × 3mm QFN package. This demo board is designed to convert a 2.7V to 12V input to a 50V output at 2mA. The LT3905 is equipped with indicators for monitoring APD current, overload, and loss-of-signal (LOS) conditions, which can easily be changed with their respective resistors. In addition, the output voltage can be adjusted via the CTRL pin. DC1956A is designed for 1MHz operation but can also be programmed for 2MHz by moving jumper JP2. 60 40 20 0 VIN = 3.3V VIN = 5V 0 0.5 1.5 1 IAPD (mA) 2 DC1956A F01 Figure 1. DC1956A Input Current vs APD Current Performance Summary Specifications are at TA = 25°C SYMBOL PARAMETER CONDITIONS VIN Input Supply Range 12 V VOUT Output Voltage Range VIN = 3.3V, IAPD = 1mA 48 50 52 V fSW Switching Frequency JP2: 1MHz 0.9 1 1.1 MHz MIN TYP 2.7 MAX UNITS ILOS Loss-of-Signal APD Current R10 = 1MΩ 12.5 µA ILIM APD Current Limit R8 = 12.4kΩ 2 mA VMON/IAPD MON Voltage to APD Current Ratio R11 = 4.99kΩ 1 mV/µA dc1956afa 1 DEMO MANUAL DC1956A Quick Start Procedure Demonstration circuit 1956 is easy to set up to evaluate the performance of the LT3905. Refer to Figure 2 for proper measurement equipment setup and follow the procedure below: NOTE. When measuring the output voltage ripple, connect a BNC cable from the oscilloscope to J1. Make sure there are no other cables connected to the APD node. 1.Place jumpers in the following positions: JP1:Run JP2:1MHz 2.With power off, connect the input power supply to VIN and GND. 2 3.Turn on the power at the input. NOTE: Make sure that the input voltage does not exceed 16V. 4.Connect a 50K resistor from APD to GND and check for the proper output voltage. VOUT = APD = 48V to 52V. NOTE: If there is no output, temporarily disconnect the load to make sure that the load is not set too high. 5.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. dc1956afa DEMO MANUAL DC1956A Quick Start Procedure Figure 2. Proper Measurement Equipment Setup dc1956afa 3 DEMO MANUAL DC1956A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C1 CAP., X7R, 1µF, 25V, 10% 0805 AVX, 0805YC105KAT2A 2 1 C5 CAP., X7R, 0.22µF, 100V, 10% 1206 AVX, 12061C224KAT2A 3 1 L1 INDUCTOR, 10µH COOPER Bussmann, SD3110-100-R 4 3 R1, R4, R5 RES., CHIP, 100k, 1/10W, 1% 0603 VISHAY, CRCW0603100KFKEA 5 3 R3, R7, R10 RES., CHIP, 1M, 1/10W, 1% 0603 VISHAY, CRCW06031M00FKEA 6 1 R8 RES., CHIP, 12.4k, 1/10W, 1% 0603 VISHAY, CRCW060312K4FKEA 7 1 R11 RES., CHIP, 4.99k, 1/10W, 1% 0603 VISHAY, CRCW0603604KFKEA 8 1 R12 RES., CHIP, 634k, 1/10W, 1% 0603 VISHAY, CRCW0603634KFKEA 9 1 R13 RES., CHIP, 15.0k, 1/10W, 1% 0603 VISHAY, CRCW060315K0FKEA 10 2 R15, R16 RES., CHIP, 0, 1/10W, 1% 0603 VISHAY, CRCW0603000Z0EA 11 1 U1 I.C. LT3905EUD, 16 PIN, 3×3mm LINEAR TECH, LT3905EUD#PBF Additional Demo Board Circuit Components 1 0 C2, C3, C4, C6 (OPT) CAP., 0603 2 0 C8 (OPT) CAP., 0805 3 1 C9 CAP., C0G, 0.5pF, 50V, 5% 0603 AVX, 06035A0R5KJAT2A 4 1 C10 CAP., X7R, 0.1µF, 16V, 10% 0603 AVX, 0603YC104KAT2A 5 2 C11, C12 CAP., X7R, 1µF, 16V, 10% 0603 AVX, 0603YC105KAT2A 6 1 Q1 TRANS., NPN 100V 2.5A MED SOT23-3 DIODES / ZETEX, ZXTN25100DFHTA 7 0 R2, R6, R9, R14, R20, R21 RES., 0603 8 2 R18, R19 RES., CHIP, 4.99k, 1/10W, 1% 0603 VISHAY, CRCW0603604KFKEA 9 1 R17 RES., CHIP, 1k, 1/10W, 1% 0603 VISHAY, CRCW06031K00FKEA 10 1 U2 I.C., LT6210CS6, TSOT23-6 LINEAR TECH, LT6210CS6#PBF 11 1 U3 I.C., LT1790BIS6-2.048, TSOT23 LINEAR TECH, LT1790BIS6-2.048 Hardware: For Demo Board Only 4 1 14 E1-E14 TESTPOINT, TURRET, .094" pbf MILL-MAX, 2501-2-00-80-00-00-07-0 2 2 JP1, JP2 3 PIN 0.079 SINGLE ROW HEADER SULLINS, NRPN031PAEN-RC 3 2 XJP1, XJP2 SHUNT, .079" CENTER SAMTEC, 2SN-BK-G 4 1 J1 CONN, BNC, 5 PINS CONNEX 112404 5 4 Stand-Off STAND-OFF, NYLON 0.25" KEYSTONE, 8831(SNAP ON) dc1956afa A B C D U3 C11 1uF R20 OPT E9 E7 E8 E6 E5 E4 E3 E1 5 3 NC 5 VIN R3 1M NC VIN LT1790BIS6-2.048 MON MON ILIM_MON LOS_MON LOS ADJ LOS ILIM CTRL EN E10 E2 OUT OPT R14 6 1MHz 2MHz JP2 C12 1uF R19 4.99K R2 OPT C3 OPT C10 0.1uF R18 C9 0 R15 R1 100K V- V+ 1 14 13 TIA 4 2 R11 4.99K (1mV/uA) OPT C2 OPT R9 LOS_MON LOS_ADJ LOS ILIM CTRL FSEL 3 8 3 R8 12.4K (2mA Limit) 3 ILIM_MON 4 MON VOUT U1 LT3905EUD 7 SW 10 EN/UVLO C4 OPT R21 OPT R5 100K 12 16 11 L1 10uH VIN COPPER BUSSMANN SD3110-100-R R10 1M (12.5uA LOS) R6 OPT R4 100K E12 U2 LT6210CS6 4.99K 0.5pF VIN VIN JP1 RUN SHDN 1 3 4 FAST MONITOR RESPONSE CIRCUIT VIN 2 R7 1M VIN C1 1uF 25V 0805 1 3 GND VIN Iset 2 VIN 2.7V - 12V 4 VIN GND 2 GND 1 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 6 GND GND APD FB 17 9 5 15 0 R16 R17 1K E11 Q1 ZXTN25100DFH C6 OPT LOAD STEP CIRCUIT R13 15.0K R12 634K PWM 2 1. ALL RESISTORS ARE 0603. ALL CAPACITORS ARE 0603. NOTE: UNLESS OTHERWISE SPECIFIED MON MONIN C5 0.22uF 100V 1206 2 E14 E13 C8 OPT 100V 0805 BNC 1 1 GND 50V / 2mA APD J1 A B C D DEMO MANUAL DC1956A Schematic Diagram dc1956afa 5 DEMO MANUAL DC1956A 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 dc1956afa Linear Technology Corporation LT 0114 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2013