DEMO MANUAL DC1863A LTC3621 17V, 1A Monolithic Synchronous Step-Down Regulator DESCRIPTION Demonstration circuit 1863 is a step-down converter, capable of delivering up to 1A of output current from a minimum input voltage of 2.7V. The DC1863A uses the power-saving LTC®3621 1MHz monolithic synchronous buck regulator in a small 8-lead MS8 package. The LTC3621 IC quiescent currents can be as low as 3.5μA in normal operation, and less than 0.1μA in shut down. The output voltage range of the DC1863A is from as low as 0.6V, the reference voltage of the LTC3621, to as high as the maximum input voltage, 17V. The DC1863A can operate in three distinct operating modes: Burst Mode® PERFORMANCE SUMMARY PARAMETER operation for highest efficiency at low output currents, forced continuous mode for lowest output ripple voltage, and pulse-skipping mode for the best compromise operation between the two other modes, by setting the mode pin to INTVCC (3.6V), INTVCC/2, or ground respectively. All these features make the DC1863A an ideal circuit for use in any high efficient, low power application. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, 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. Specifications are at TA = 25°C CONDITIONS VALUE Input Voltage Range 2.7V to 17V Output Voltage Range 0.6V to VIN Run/Shutdown Output Voltage Regulation Typical Output Ripple Voltage RUN Pin = GND Shutdown RUN Pin = VIN Operating VIN = 2.7V to 17V, IOUT = 0A to 1A 1.2V ±3% Typ (1.164V to 1.236V) VIN = 2.7V to 17V, IOUT = 0A to 1A 1.8V ±3% Typ (1.746V to 1.854V) VIN = 2.7V to 17V, IOUT = 0A to 1A 2.5V ±3% Typ (2.425V to 2.575V) VIN = 3.5V to 17V, IOUT = 0A to 1A 3.3V ±3% Typ (3.201V to 3.399V) VIN = 5.2V to 17V, IOUT = 0A to 1A 5V ±3% Typ (4.85V to 5.15V) VIN = 12V, VOUT = 5V, IOUT = 1A (20MHz BW) <20mVP–P Nominal Switching Frequency Operation Modes Burst Mode-to-CCM Operation 1MHz ± 8% MODE Pin = INTVCC Burst Mode MODE Pin = GND Pulse-Skipping MODE Pin = INTVCC/2 Forced Continuous VIN = 12V, VOUT = 1.2V IOUT < 500mA INTVCC 3.6V ±8.33% (3.3V to 3.9V) Table 2. Jumper Description JUMPER FUNCTION/RANGE SETTING JP1 Run: ON–OFF. ON JP2 Mode: Burst Mode Operation (BM) or PulseSkipping Mode (PS). BM JP3 Output Voltage Setting 1.2V dc1863af 1 DEMO MANUAL DC1863A QUICK START PROCEDURE Demonstration Circuit 1863 is easy to set up to evaluate the performance of the LTC3621. For proper measurement equipment configuration, set up the circuit according to the diagram in Figure 1. Before proceeding to test, check that the shunts are inserted into the correct locations: 1.2V position of the output voltage header JP3, into the BM (Burst Mode operation) position of MODE header JP2, and into the ON position of RUN header JP1. 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 measurement technique. With the DC1863 set up according to the proper measurement configuration and equipment in Figure 1, apply 5V at VIN (Do not hot-plug VIN or increase VIN over the rated maximum supply voltage of 17V, or the part may be damaged.). Measure VOUT; it should read 1.2V (If desired, the quiescent current of the circuit can be monitored now by swapping the shunt in header JP1 into the OFF position). The output voltage should be regulating. Draw 500mA out of the output and measure VOUT—it should measure 1.2V ±2% (1.176V to 1.224V). Verify the switching frequency is between 920kHz and 1.08MHz (T = 1.08μs and 926ns), and that the switch node waveform is rectangular in shape. (1.164V to 1.236V). Measure the output ripple voltage; it should measure less than 20mV AC. Set the input voltage to 12V and the output current to than 100mA. Observe the Burst Mode operation at the switch node (the pad of the inductor opposite from the output), and measure the output ripple voltage. It should measure less than 100mV. Change the shunt position on the MODE header from BM to PS (pulse-skipping mode) and observe the voltage waveform at the switch pins. To achieve forced continuous operation, insert two 100k resistors at the pads for R1 and R2. These resistors develop a voltage of INTVCC/2 at the mode pin, which is the voltage setting for forced continuous operation. Insert the JP1 shunt into the OFF position and move the shunt in the 1.2V output JP3 header into any of the remaining output voltage option headers: 1.8V (JP4), 2.5V (JP5), 3.3V (JP6) or 5V (JP7). Just as in the 1.2V VOUT test, the output voltage should read VOUT ±2% tolerance under static line and load conditions and ±1% tolerance under dynamic line and load conditions (±3% total). Also, the circuit switch operation in Burst or pulse-skipping mode will remain the same. There is an extra output voltage header, JP8, to allow the user to easily set the output to their desired value When finished, turn off the circuit by inserting the shunt in header JP1 into the OFF position. Vary the input voltage from 2.7V to 17V and the load current from 0 to 1A. VOUT should regulate around 1.2V ±3% Figure 1. Proper Equipment Measurement Setup dc1863af 2 DEMO MANUAL DC1863A QUICK START PROCEDURE Figure 2. Measuring Input or Output Ripple EFFICIENCY DATA VIN = 12V Burst Mode OPERATION fSW = 1MHZ L = 4.7μH COILCRAFT XFL-4020 Figure 3. Efficiency vs Load Current dc1863af 3 DEMO MANUAL DC1863A LOAD STEP RESPONSE WAVEFORMS VOUT 50mV/DIV AC-COUPLED IOUT 500mA/DIV VIN = 12V 50μs/DIV VOUT = 1.2V 500mA LOAD STEP (500mA TO 1A) PULSE-SKIPPING MODE fSW = 1MHz Figure 4 VOUT 50mV/DIV AC-COUPLED IOUT 500mA/DIV VIN = 12V 50μs/DIV VOUT = 1.8V 500mA LOAD STEP (500mA TO 1A) PULSE-SKIPPING MODE fSW = 1MHz Figure 5 VOUT 50mV/DIV AC-COUPLED IOUT 500mA/DIV VIN = 12V 50μs/DIV VOUT = 2.5V 500mA LOAD STEP (500mA TO 1A) PULSE-SKIPPING MODE fSW = 1MHz Figure 6 dc1863af 4 DEMO MANUAL DC1863A LOAD STEP RESPONSE WAVEFORMS VOUT 100mV/DIV AC-COUPLED IOUT 500mA/DIV VIN = 12V 50μs/DIV VOUT = 3.3V 500mA LOAD STEP (500mA TO 1A) PULSE-SKIPPING MODE fSW = 1MHz Figure 7 VOUT 100mV/DIV AC-COUPLED IOUT 500mA/DIV VIN = 12V 50μs/DIV VOUT = 5V 500mA LOAD STEP (500mA TO 1A) PULSE-SKIPPING MODE fSW = 1MHz Figure 8 dc1863af 5 DEMO MANUAL DC1863A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 CFF CAP., X7R, 22pF, 50V, 0402 AVX 04025A220KAT 2 1 C1 CAP., X5R, 10μF, 25V, 10%, 1206 AVX 12063D106KAT 3 2 C2, C3 CAP., X5R, 22μF, 25V, 10%, 1206 AVX 12063D226KAT 4 1 C4 CAP., X5R, 1μF, 6.3V,20%, 0402 TDK, C1005X5R0J105M 5 1 L1 IND., FIXED INDUCTOR, 4.7μH COILCRAFT XFL4020-472MEB 6 2 R3, Rset RES., CHIP, 619k, 1%, 0402 VISHAY CRCW0402619KFKED 7 1 U1 LTC3621EMS8E, MS8 PACKAGE, 8-LEAD, MSOP LINEAR TECH. LTC3621EMS8E#PBF Additional Demo Board Circuit Components 1 1 C1A CAP., X5R, 8.2μF 20V, SIZE B2, 3528-7343 SANYO 20TQC8R2M 2 0 R1, R2 OPT RES., CHIP, 0402 3 1 Rpgood RES., CHIP, 100k, 1%, 0402 VISHAY CRCW0402100K0FKED 4 1 R4 RES., CHIP, 309k, 1%, 0402 VISHAY CRCW0402309KFKED 5 1 R5 RES., CHIP, 196k, 1%, 0402 VISHAY CRCW0402196KFKED 6 1 R6 RES., CHIP, 137k, 1%, 0402 VISHAY CRCW0402137KFKED 7 1 R7 RES., CHIP, 84.5k, 1%, 0402 VISHAY CRCW040284K5FKED 8 0 R8 OPT RES., CHIP, 0402 1 8 E1-E8 TESTPOINT, TURRET, 0.095" MILL-MAX 2501-2-00-80-00-00-07-0 2 2 JP1, JP2 2MM SINGLE ROW HEADER, 3-PIN SULLINS NRPN031PAEN-RC 3 6 JP3-JP8 2MM SINGLE ROW HEADER, 2-PIN SULLINS NRPN021PAEN-RC 4 3 JP1-JP3 SHUNT SAMTEC 2SN-BK-G Hardware dc1863af 6 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 E7 E8 E1 + BM (Burst Mode) C1A 8.2uF 25V VIN GND SYNC 5 E3 E5 MODE/SYNC (Forced Continuous) PS (Pulse-Skip) INTVCC PGOOD VIN 2.7V - 17V JP2 2 C1 10uF 1 3 ON OFF R1 100k OPT R2 100k OPT Rpgood 100k 4 1 RUN 4 2 JP1 C4 1uF 3 5 6 4 3 2 9 8 5 1 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. 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. CUSTOMER NOTICE 7 FB SW GND SGND LTC3621EMS8E MODE/SYNC INTVCC PGOOD RUN VIN U1 3 HZ SCALE = NONE APP ENG. TOM G. PCB DES. APPROVALS JP4 1.8V JP3 R4 309k 1.2V R3 619k 4.7uH L1 3.3V JP6 R6 137k 2 DATE: N/A SIZE JP8 USER SELECT R8 OPT CFF 22pF C2 22uF VOUT E6 E4 C3 22uF E2 TOM G. APPROVED 1 2 Thursday, June 13, 2013 LTC3621EMS8E DEMO CIRCUIT 1863A 1 SHEET 1 17V VIN SYNCHRONOUS STEP-DOWN REGULATOR WITH ULTRA-LOW QUIESCENT CURRENT IC NO. DATE GND GND 1A VOUT 11-29-12 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 PRODUCTION DESCRIPTION REVISION HISTORY TECHNOLOGY 5.0V JP7 R7 84.5k REV TITLE: SCHEMATIC 2.5V JP5 R5 196k Rset 619k __ ECO 2 A B C D DEMO MANUAL DC1863A SCHEMATIC DIAGRAM dc1863af 7 DEMO MANUAL DC1863A 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 dc1863af 8 Linear Technology Corporation LT 1013 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2013