DEMO MANUAL DC1797A LTC3536 1A, Low Noise, Wide VIN Buck-Boost DC/DC Converter Description Demonstration circuit 1797A is a combined step-up and step-down DC/DC converter using the LTC®3536 monolithic synchronous buck-boost regulator. The DC1797A 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 DC1797A can be set as low as 1.8V and can go as high as 5.5V. The DC1797A supports two operational 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. The DC1797A consumes less than 28µA of quiescent current during Burst Mode operation, and during shutdown, it consumes less than 1µA. The DC1797A 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 DC1797A, small, low profile surface mount components are used in the circuit. These features, plus the LTC3536 availability in a small 10-lead DFN package, make the DC1797A a perfect match for battery-powered, hand-held applications. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, µModule, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. PERFORMANCE SUMMARY PARAMETER 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 External Clock Sync. Frequency Range 300kHz to 2MHz Efficiency VIN = 5V, VOUT = 3.3V, IOUT = 0.2A 95% Typical Output Ripple VOUT VIN = 5V, IOUT = 1A (20MHz Bandwidth) < 15mVP-P Burst Mode Operation VIN = 5V, VOUT = 3.3V VIN = 2.5V, VOUT = 3.3V < 0.15A < 0.1A dc1797af 1 DEMO MANUAL DC1797A quick start procedure Demonstration circuit 1797A 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 frequency and JP2 off positions, which connects the RUN pin to ground (GND), and thus, shutdown the circuit. 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. 1.With the DC1797 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. 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 ±% (Do not apply more than the rated maximum voltage of 5.5V to the board or the part may be damaged). 3.Vary the converter load, which should not exceed 1A at VIN 5.0V. 4.Vary the input voltage from 1.8V to 5.5V, the available output current depends on the input voltage, see the LTC3536 data sheet for details. 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 operation should no exceed 0.15A at VIN 5.0V and 0.1A at 2.5V, see the LTC3536 data sheet for details. Figure 1. Proper Measurement Equipment Setup dc1797af 2 DEMO MANUAL DC1797A Quick Start Procedure GND VIN 100 100 95 90 90 80 85 70 EFFICIENCY (%) EFFICIENCY (%) Figure 2. Measuring Input or Output Ripple 80 75 70 65 60 60 50 40 FIXED FREQUENCY MODE 30 20 ILOAD = 200mA ILOAD = 1A 55 50 1.5 Burst Mode OPERATION 2 2.5 3 3.5 4 4.5 INPUT VOLTAGE (V) 5 5.5 0 0.001 DC1797A F03 Figure 3. Efficiency vs Input Voltage VIN = 5.5V VIN = 2.5V VIN = 1.8V 10 0.01 0.1 LOAD CURRENT (A) 1 DC1797A F04 Figure 4. Efficiency vs Input Voltage for Fixed Frequency and Burst Mode Operation 14mVP-P DC1797A F05 Figure 5. Output Noise, VIN = 4.5V, IOUT = 1A dc1797af 3 DEMO MANUAL DC1797A parts list ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER, PART NUMBER Required Circuit Components 1 1 C1 Capacitor Ceramic 10µF 10V X5R 10% 0805 Murata, GRM21BR61A106KE19L 2 2 C2, C4 Capacitor Ceramic 1.0µF 10V X7R 20% 0603 AVX, 06036C105MAT2A 3 1 C3 Capacitor Ceramic 22µF 6.3V X5R 10% 1206 AVX, 12066D226KAT2A 4 1 C5 Capacitor Ceramic 47PF 50V C0G 5% 0402 TDK, C1005C0G1H470J 5 1 C7 Capacitor Ceramic 220PF 50V C0G 5% 0402 Murata, GRM1555C1H221JA01D 6 1 L1 Inductor, 4.7µH Coilcraft XFL4020-472MEC 7 3 R1, R7, R8 Resistor 1.00MΩ 1/16W 1% 0402 SMD Vishay, CRCW04021M00FK 8 1 R2 Resistor 220kΩ 1/16W 1% 0402 SMD Vishay, CRCW0402220KFKED 9 1 R3 Resistor 6.49kΩ 1/16W 1% 0402 SMD Vishay, CRCW04026K49FKED 10 1 R4 Resistor 49.9kΩ 1/16W 1% 0402 SMD Vishay, CRCW040249K9FKED 11 1 R6 Resistor 100kΩ 1/16W 1% 0402 SMD Vishay, CRCW0402100KFKED 12 1 U1 Buck-Boost Converter Linear Technology, LTC3536EDD Additional Demo Board Circuit Components 1 0 C6 Capacitor, POSCAP 47µF 10V Sanyo, 10TPB47MC, Optional 2 0 C8 Capacitor C0G 0402 Optional 3 0 R5 Resistor, 0402 Optional 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 Diameter 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 dc1797af 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 VIN + C6 OPT VIN R8 1 Meg OFF ON JP2 RUN C1 10uF 10V VIN 1 2 3 5 2. INSTALL SHUNTS AS SHOWN. 1. ALL RESISTORS ARE 0402 AND CAPACITORS ARE 0603. NOTE: UNLESS OTHERWISE SPECIFIED MODE 1 BURST MODE 2 3 FIXED FREQ JP1 GND SYNC GND E2 E1 VIN 1.8V - 5.5V R7 1 Meg 4 C2 1uF 10V 4 R6 100k R5 OPT LTC3536EDD 2 SGND 1 RT SW2 5 49.9K R4 CUSTOMER NOTICE SHDN 8 VC 10 FB 9 VOUT 6 C8 OPT 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 2 R3 6.49K C5 47pF R2 220K 1% 2 DATE: N/A SIZE 04-11-11 IC NO. E4 GND DATE 04-11-11 VOUT 3.3V / 1A 1 SHEET 1 1A LOW NOISE, WIDE VIN BUCK-BOOST DC / DC CONVERTER LTC3536EDD DEMO CIRCUIT 1797A TECHNOLOGY C4 1uF 10V E3 VICTOR K. APPROVED OF 1 2 REV. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only C3 22uF 6.3V DESCRIPTION PRODUCTION FAB 2 1 REVISION HISTORY REV R1 1 Meg 1% __ ECO VICTOR K. TITLE: SCHEMATIC SCALE = NONE APP ENG. NC APPROVALS PCB DES. 220pF C7 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. 3 MODE/SYNC 7 VIN 4 SW1 U1 3 L1 XFL4020 - 472 4.7uH PGND 11 5 A B C D DEMO MANUAL DC1797A Schematic Diagram dc1797af 5 DEMO MANUAL DC1797A 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 dc1797af 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