LMZ142033A

LMZ14203 3A Demo Board SIMPLE SWITCHER® Power Module Quick Start Guide LMZ14203 3A Demo Board SIMPLE SWITCHER® Power Module Quick Start Guide Description The LMZ14203 SIMPLE SWITCHER power module is a complete, easy to use step-down DC-DC solution capable of driving up to 3A load. The LMZ14203 is available in an innovative, easy to use package that enhances thermal performance and allows for hand or machine soldering. The LMZ14203 demo board can accept an input voltage rail between 8V and 42V and deliver an adjustable and highly accurate output voltage as low as 0.8V. The LMZ14203 only requires three external resistors and four external capacitors to complete the power solution. The LMZ14203 is a reliable and robust solution with the following protection features: thermal shutdown, input under-voltage lockout, output overvoltage protection, short-circuit protection, output current limit, and allows startup into a pre-biased output. A single resistor adjusts switching frequency up to 1 MHz. National Semiconductor Application Note 2032 Alan Martin January 22, 2010 Demo Board Features • • • • • • • • • • • • • • Power input voltage range 6V-42V UVLO programmed at 8V Adjustable output voltage range 0.8V to 6V Up to 3A output current Integrated shielded inductor in module Efficiency up to 92% All ceramic capacitor design No loop compensation required Starts into pre-biased loads Short circuit protection Thermal Shutdown Only 9 external passives plus module Max 78°C ambient at full load 2 layer low cost assembly Packaging Highlights • • • • • 7 lead module package (Similar to TO-263) Single exposed die attach pad for enhanced thermal performance 10.2 x 13.8 x 4.6 mm module package High power density 1.7” x 2.3” reduced size demo board form factor Typical Applications • • • • • Point of load conversions from 12V and 24V input rail Space constrained applications Industrial controls Telecom Networking equipment AN-2032 30114401 30114402 Front View Back View © 2010 National Semiconductor Corporation 301144 www.national.com AN-2032 Absolute Maximum Module Ratings VIN, RON to GND -0.3V to 47 EN, FB, SS to GND -0.3V to 7V Demo Board Operating Ratings VIN VOUT (Default setting) IOUT 6V to 42V 3.3V 0A to 3A Module Operating Ratings VIN 6V to 42V EN (Input on pin 3 0V to 6.5V module pin) Junction Temperature Range (Tj) - 40C to +125C EN (Input on demo 0V to 42V board post) UVLO setting on ENable input Soft-start time Operating Temperature Range (Tj) 8V 2.2 mSec - 40C to +78C (at full 3A load) Demo Board Schematic 30114403 www.national.com 2 AN-2032 Demo Board Bill of Materials Ref Des RON RENT RENB RFBT RFBB CFF CSS CIN1 CO1 CO2 U1 Description 61.9 kohm 1% resistor 68.1 kohm 1% resistor 11.8 kohm 1% resistor 3.32 kohm 1% resistor 1.07 kohm 1% resistor Case 603 603 603 603 603 Manufacturer Part Number 0.022 uF 50V X7R 603 ceramic capacitor 0.022 uF 50V X7R 603 ceramic capacitor 10 uF 50V X5R 1210 ceramic capacitor 1.0 uF 50V X7R 1206 ceramic capacitor 100 uF 6.3V X5R 1210 ceramic capacitor LMZ14203 SIMPLE SWITCHER Power Module TOPMOD UMK325BJ106M M-T UMK316B7105KL -T JMK325BJ107M M-T LMZ14203TZADJ Alternate resistor values for alternative output voltages VOUT 6 5 3.3 2.5 1.8 1.5 1.2 0.8 RFBT 2.49k 5.62k 3.32k 2.26k 1.87k 1.00k 4.22k 0.0K RFBB 3.83k 1.07k 1.07k 1.07k 1.50k 1.13k 8.45k 39.2k RON 124k 100k 61.9k 47.5k 32.4k 28.0k 22.6k 24.9k Demo Board Hookup VOUT Connect the load to VOUT and one of the GND posts. The module can source up to a 3A load current. VIN : Connect Vin to a positive voltage in the 8 to 42V range. Connect the negative terminal of the source supply to one of the posts labeled GND. En: The Enable input post is configured for direct connection to the Vin post. The on-board resistive voltage divider is chosen such that when connected to 42V that the enable input at pin 3 of the module will not exceed 6.5V. With the chosen resistor values this results in an under voltage lockout level of 8 V input. The top enable resistor is RENT (aka REN1) and the bottom enable resistor is RENB (aka REN2). The bottom enable resistor may have a location for a shunt zener clamp (Labeled D1 OPT in the silkscreen - Included only in the later revisions of the assembly.) Quiescent current: If the Enable post is disconnected, the module will be disabled and about 20 uA of supply current will flow from Vin to ground while in the disabled mode. With the enable input connected to Vin via the 68.1K/11.8K divider there will be about 1.5 mA of no-load quiescent current into the Vin input. Additional current flows into the enable divider string. Demo Board Passive Components Soft-start capacitor The soft-start capacitor controls the rise time of the output voltage when power is first applied and following the clearing of a fault mode. Feedback dividerRegulator output voltage is programmed though the selection of the two resistors, RFBT ( aka RFB1) and RFB (aka RFB2) A feed forward capacitor (CFF) is located in parallel with the upper feedback divider resistor. This capacitor improves the step response to abrupt changes in 3 www.national.com AN-2032 load current. Refer to the table above when modifying the board for a different output voltage. Resistor values shown will minimize error in output voltage setting. RON Resistor: The primary function of the RON resistor is to set the On-Time interval of the internal control section switching cycle. The secondary function of the RON resistor is to create a nearly constant operating frequency over the input operating voltage range. If the output voltage of the regulator is changed by adjusting the feedback divider then it is generally required that the RON resistor value also be changed in order to maintain the same operating frequency. Cout A parallel connection of a 1uF 50V and a 100uF 6.3V multilayer ceramic are used for the output capacitor. Locations are provided on the PCB assembly for experimenting with additional output capacitors. Some recommended values are shown on the schematic as “DNS” and labeled in the PCB silkscreen as “OPT”. CinA 10 uF 50V multilayer ceramic is connected as the input filter. Locations are provided on the PCB assembly for experimenting with additional input capacitors. Some recommended values are shown on the schematic as “DNS” and labeled in the PCB silkscreen as “OPT”. Performance Characteristics Efficiency 24V Input@ 25°C Dissipation, 24V Input@ 25°C 30114404 30114405 Line and Load Regulation @ 25°C Transient Response 24VIN 3.3Vo 0.6A to 3A Step 30114407 30114406 www.national.com 4 AN-2032 Notes 5 www.national.com LMZ14203 3A Demo Board SIMPLE SWITCHER® Power Module Quick Start Guide Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Amplifiers Audio Clock and Timing Data Converters Interface LVDS Power Management Switching Regulators LDOs LED Lighting Voltage References PowerWise® Solutions Temperature Sensors PLL/VCO www.national.com/amplifiers www.national.com/audio www.national.com/timing www.national.com/adc www.national.com/interface www.national.com/lvds www.national.com/power www.national.com/switchers www.national.com/ldo www.national.com/led www.national.com/vref www.national.com/powerwise WEBENCH® Tools App Notes Reference Designs Samples Eval Boards Packaging Green Compliance Distributors Quality and Reliability Feedback/Support Design Made Easy Design Support www.national.com/webench www.national.com/appnotes www.national.com/refdesigns www.national.com/samples www.national.com/evalboards www.national.com/packaging www.national.com/quality/green www.national.com/contacts www.national.com/quality www.national.com/feedback www.national.com/easy www.national.com/solutions www.national.com/milaero www.national.com/solarmagic www.national.com/training Applications & Markets Mil/Aero PowerWise® Design University Serial Digital Interface (SDI) www.national.com/sdi www.national.com/wireless www.national.com/tempsensors SolarMagic™ THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS, IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS. EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. Copyright© 2010 National Semiconductor Corporation AN-2032 For the most current product information visit us at www.national.com National Semiconductor Americas Technical Support Center Email: support@nsc.com Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Technical Support Center Email: europe.support@nsc.com National Semiconductor Asia Pacific Technical Support Center Email: ap.support@nsc.com National Semiconductor Japan Technical Support Center Email: jpn.feedback@nsc.com