DEMO MANUAL DC1852A LTC3536 1A, Low Noise, Wide VIN Buck-Boost DC/DC Converter DESCRIPTION Demonstration circuit 1852A is a combined step-up and step-down DC/DC converter, using the LTC3536 monolithic synchronous buck-boost regulator. The DC1852A has wide input voltage range of 1.8V to 5.5V and is capable of delivering up to 1A of output current. The output voltage of the DC1852A can be set as low as 1.8V and can go as high as 5.5V. DC1852A supports two operation modes: fixed-frequency pulse-width modulation (PWM) and Burst Mode® operation. Fixed-frequency mode of operation maximizes the output current, reduces output voltage ripple, and yields a low noise switching spectrum. Burst Mode operation employs a variable frequency switching algorithm that minimizes the no-load input quiescent current and improves efficiency at light loads. PERFORMANCE SUMMARY PARAMETER The DC1852A consumes less than 28μA of quiescent current during Burst Mode operation, and during shutdown, it consumes less than 1μA. The DC1852A has a standard operating frequency of 1MHz, but can be adjusted to frequencies as high as 2MHz. If Pin 1 (RT) is tied to VIN, the default switching frequency is 1.2MHz. Because of the high switching frequency of the DC1852A, small, low profile surface mount components are used in the circuit. These features, plus the LTC3536’s small 12-lead MSOP package, make the DC1852A a perfect match for batterypowered, handheld applications. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, μModule, 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 1.8V Maximum Input Voltage 5.5V Output Voltage VOUT Regulation VIN = 1.8V to 5.5V 3.3V ±2% Maximum Continuous Output Current Fixed Frequency Mode 1A Preset Operating Frequency R6 = 100kΩ 1MHz Efficiency VIN = 5V, VOUT = 3.3V, IOUT = 1A 95% Typical Output Ripple VOUT VIN = 5V, IOUT = 1A (20MHz BW) <15mVP-P Burst Mode Operation VIN = 5V, VOUT = 3.3V VIN = 2.5V, VOUT = 3.3V <0.15A <0.1A External Clock Sync. Frequency Range 300kHz to 2MHz dc1852af 1 DEMO MANUAL DC1852A QUICK START PROCEDURE Demonstration circuit 1852A is easy to set up to evaluate the performance of the LTC3536. For proper measurement equipment configuration, set up the circuit according to the diagram in Figure 1. Before proceeding to test, insert shunts into JP1 FIXED FREQ and JP2 OFF positions, which connects the RUN pin to ground (GND), and thus, shut down the circuit. 2. Turn on the circuit by inserting the shunt in header JP2 into the ON position. The output voltage should be regulating. Measure VOUT– it should measure 3.3V ±1% (Do not apply more than the rated maximum voltage of 5.5V to the board or the part may be damaged). 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 VIN or VOUT and GND terminals. See Figure 2 for proper scope probe technique. 4. Vary the input voltage from 1.8V to 5.5V, the available output current depends on the input voltage, see LTC3536 data sheet for details. 1. With the DC1852 set up according to the proper measurement and equipment in Figure 1, apply 5V at VIN. Measure VOUT; it should read 0V. If desired, one can measure the shutdown supply current at this point. The supply current will be approximately 3μA, or less, in shutdown. 3. Vary the converter load, which should not exceed 1A at VIN 5V. 5. Set output current to zero and move jumper JP2 into Burst Mode position and measure VOUT– it should register 3.3V ±1%. 6. Vary the input voltage from 1.8V to 5.5V, the available output current depends on the input voltage. Load in Burst Mode should no exceed 0.15A at VIN 5V and 0.1A at 2.5V, see LTC3536 data sheet for details. + + Figure 1. Proper Measurement Equipment Setup dc1852af 2 DEMO MANUAL DC1852A QUICK START PROCEDURE GND VIN Figure 2. Measuring Input or output Ripple 100 100 ILOAD = 200mA 95 90 80 85 ILOAD = 1A 80 EFFICIENCY (%) EFFICIENCY (%) 90 75 70 70 60 50 40 65 30 60 20 55 10 50 1.5 2.0 2.5 3.0 3.5 4.0 4.5 INPUT VOLTAGE (V) 5.0 5.5 0 0.001 dc1852a F03 Figure 3. Efficiency vs Input Voltage VIN = 1.8V VIN = 2.5V VIN = 5.5V VIN = 1.8V BURST VIN = 2.5V BURST VIN = 5.5V BURST 0.01 0.1 LOAD CURRENT (A) 1 dc1852a F04 Figure 4. Efficiency vs Input Voltage for Fixed Frequency and Burst Mode Operation Figure 5. Output Noise, VIN 4.5V, IO 1A dc1852af 3 DEMO MANUAL DC1852A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C1 CAP CER 10μF 10V X5R 10% 0805 MURATA, GRM21BR61A106KE19L 2 2 C2, C4 CAP CER 1μF 10V X7R 20% 0603 AVX, 06036C105MAT2A 3 1 C3 CAP CER 22μF 6.3V X5R 10% 1206 AVX, 12066D226KAT2A 4 1 C5 CAP CER 47pF 50V C0G 5% 0402 TDK, C1005C0G1H470J 5 1 C7 CAP CER 220pF 50V C0G 5% 0402 MURATA, GRM1555C1H221JA01D 6 1 L1 INDUCTOR, 4.7μH COILCRAFT XFL4020-472MEC 7 3 R1, R7, R8 RES 1mΩ 1/16W 1% 0402 SMD VISHAY, CRCW04021M00FK 8 1 R2 RES 220k 1/16W 1% 0402 SMD VISHAY, CRCW0402220KFKED 9 1 R3 RES 6.49k 1/16W 1% 0402 SMD VISHAY, CRCW04026K49FKED 10 1 R4 RES 49.9k 1/16W 1% 0402 SMD VISHAY, CRCW040249K9FKED 11 1 R6 RES 100k 1/16W 1% 0402 SMD VISHAY, CRCW0402100KFKED 12 1 U1 BUCK-BOOST CONVERTER LINEAR TECHNOLOGY, LTC3536EMSE Additional Demo Board Circuit Components 1 0 C6 CAP POSCAP 47μF 10V SANYO, 10TPB47MC, OPT 2 0 C8 CAP C0G 0402 OPT 3 0 R5 RES 0402 OPT 1 4 MH1-MH4 STAND-OFF, NYLON (SNAP ON), 0.375" TALL KEYSTONE, 8832 2 6 E1, E2, E3, E4, E5, E6 TURRET, 0.09 DIA MILL-MAX, 2501-2-00-80-00-00-07-0 3 2 JP2, JP1 HEADERS, 3 PINS, 2mm CTRs SAMTEC, TMM-103-02-L-S 4 2 XJP1, XJP2 SHUNT, 2mm CTRs SAMTEC, 2SN-BK-G 5 1 FAB, PRINTED CIRCUIT BOARD DEMO CIRCUIT 1797A-2 Hardware dc1852af 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 D E6 E5 E2 JP2 RUN JP1 MODE VIN VIN 1 2 3 VIN 1 2 3 + C6 OPT R7 1 Meg R8 1 Meg C1 10uF 10V 0805 5 2. INSTALL SHUNTS AS SHOWN. 1. ALL RESISTORS AND CAPACITORS ARE 0402. NOTE: UNLESS OTHERWISE SPECIFIED OFF ON FIXED FREQ BURST MODE GND SYNC GND E1 VIN 1.8V - 5.5V OPT 100k 4 R5 R6 C2 1uF 10V 0603 4 2 1 3 9 8 4 SGND RT MODE/SYNC VIN VIN SW1 U1 LTC3536EMSE 5 10 12 11 7 6 49.9K R4 CUSTOMER NOTICE PGND SHDN VC FB VOUT SW2 3 C8 OPT 220pF C7 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 2 R2 220K 1% R1 1 Meg 1% 2 SCALE = NONE DATE: N/A SIZE TECHNOLOGY C9 OPT 1206 1 C4 1uF 10V 0603 E4 E3 GND 06-27-11 IC NO. DATE 06-27-11 VOUT 3.3V / 1A VICTOR K. APPROVED 1 LTC3536EMSE DEMO CIRCUIT 1852A SHEET 1 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 1ST PROTOTYPE DESCRIPTION REVISION HISTORY 1A, LOW NOISE, BUCK-BOOST REGULATOR VICTOR K. TITLE: SCHEMATIC APP ENG. C3 22uF 6.3V 1206 1 REV LT __ ECO PCB DES. APPROVALS R3 6.49K C5 47pF LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. L1 XFL4020 - 472 4.7uH PGND 13 5 A B C D DEMO MANUAL DC1852A SCHEMATIC DIAGRAM dc1852af 5 DEMO MANUAL DC1852A 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 dc1852af 6 Linear Technology Corporation LT 0711 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2011