National Semiconductor Application Note 2089 Denislav D. Petkov January 7, 2011 Introduction Board Specifications The LMZ14203H/02H/01H SIMPLE SWITCHER® power modules for high output voltage are easy-to-use DC-DC solutions capable of driving up to a 3A load with exceptional power conversion efficiency, output voltage accuracy, line and load regulation. They are available in an innovative package that enhances thermal performance and allows for hand or machine soldering. The LMZ14203H/02H/01H Evaluation Board is configured for 12V output voltage from 15V to 42V input. The precision enable input allows for programmable UVLO of the input supply. The resistor voltage divider RENT and RENB set the input UVLO threshold. Connect the VIN turret terminal to the EN turret on the board to enable operation. The external soft-start capacitor CSS facilitates controlled startup output rise time. The resistors RFBT and R FBB set the output voltage. An output feed-forward capacitor CFF across the upper feedback resistor trims for optimum transient response. The control loop operates well with low ESR output capacitors such as ceramic and polymer electrolytic capacitors. The resistor RON sets the operating frequency. See datasheet for component selection details. The LMZ14203H/02H/01H PCB layout offers excellent thermal performance, achieving junction-to-ambient thermal resistance θJA of 14.9°C/W. The evaluation board with its default Bill of Materials offers great EMI performance, complying with the EN 55022 Class B radiated emissions standard. The solution also complies with the CISPR22 conducted emissions standard with the addition of a small input filter. • • • • • • • • • • • VIN = 15V to 42V VOUT = 12V 3A max load at 24VIN and 65°C TAMB Low radiated EMI (EN 55022 Class B compliant) 400kHz switching frequency Enable UVLO set at 13.5V θJA = 14.9°C/W 4 copper layers 2 oz copper on top and bottom layer 1 oz copper on internal layers 6.985 cm x 7.620 cm (2.75 in x 3 in) with 1.575 cm (.062 in) thickness of FR4 laminate material Additional Footprints Additional component mounting pads are available to experiment with alternative input and output capacitor combinations or a zener clamp on the enable input. See Figure 6 for corresponding schematic locations. AN-2089 30137701 FIGURE 1. Evaluation Board Schematic © 2011 National Semiconductor Corporation 301377 LMZ14203H/02H/01H Evaluation Board LMZ14203H/02H/01H Evaluation Board www.national.com AN-2089 TABLE 1. LMZ1420xH Bill of Materials, VIN = 15V to 42V, VOUT = 12V, IOUT (MAX) = 3A / 2A / 1A Designator Description Case Size Manufacturer Manufacturer P/N Quantity U1 SIMPLE SWITCHER® TO-PMOD-7 National Semiconductor LMZ14203HTZ or LMZ14202HTZ or LMZ14201HTZ 1 CIN4, CO1 1 µF, X7R, 50V 1206 Taiyo Yuden UMK316B7105KL-T 2 CIN2 10 µF, X5R, 50V 1210 Taiyo Yuden UMK325BJ106MM-T 1 CO3 47 µF, 35 mΩ, 16V, Polymer 7343-43 KEMET T525D476M016ATE035 1 CFF 0.022 µF, X7R, 100V 0805 AVX 08051C223JAT2A 1 CSS 4700 pF, X7R, 25V 0805 AVX 08053A472JAT2A 1 RENB 11.8 kΩ 0805 Panasonic ERJ-6ENF1182V 1 RENT 124 kΩ 0805 Panasonic ERJ-6ENF1243V 1 RFBT 34 kΩ 0805 Vishay-Dale CRCW080534K0FKEA 1 RFBB 2.43 kΩ 0805 Panasonic ERJ-6ENF2431V 1 RON 249 kΩ 0805 Vishay-Dale CRCW0805249KFKEA 1 www.national.com 2 AN-2089 Performance Characteristics Unless otherwise specified the following conditions apply: VIN = 24V, VOUT = 12V, TAMB = 25°C LMZ14203H Thermal Derating 100 3.5 95 3.0 OUTPUT CURRENT (A) EFFICIENCY (%) LMZ14203H Efficiency 90 85 80 75 70 0.0 VIN = 15V VIN = 24V VIN = 30V VIN = 36V VIN = 42V 0.5 1.0 1.5 2.0 2.5 OUTPUT CURRENT (A) 2.5 2.0 1.5 1.0 0.5 0.0 3.0 -20 VIN = 15V VIN = 24V VIN = 42V 0 20 40 60 80 100 120 140 AMBIENT TEMPERATURE (°C) 30137739 30137740 LMZ14202H Efficiency LMZ14202H Thermal Derating 100 2.5 OUTPUT CURRENT (A) EFFICIENCY (%) 95 90 85 80 75 70 0.0 VIN = 15V VIN = 24V VIN = 30V VIN = 36V VIN = 42V 0.5 1.0 1.5 OUTPUT CURRENT (A) 2.0 1.5 1.0 0.5 0.0 2.0 -20 VIN = 15V VIN = 24V VIN = 42V 0 20 40 60 80 100 120 140 AMBIENT TEMPERATURE (°C) 30137742 30137743 LMZ14201H Thermal Derating 100 1.2 95 1.0 OUTPUT CURRENT (A) EFFICIENCY (%) LMZ14201H Efficiency 90 85 80 75 70 0.0 VIN = 15V VIN = 24V VIN = 30V VIN = 36V VIN = 42V 0.2 0.4 0.6 0.8 OUTPUT CURRENT (A) 0.8 0.6 0.4 0.2 0.0 1.0 -20 30137745 VIN = 15V VIN = 24V VIN = 42V 0 20 40 60 80 100 120 140 AMBIENT TEMPERATURE (°C) 30137746 3 www.national.com AN-2089 LMZ14203H Startup LMZ14203H Line and Load Regulation OUTPUT VOLTAGE (V) 12.6 VIN = 15V VIN = 24V VIN = 30V VIN = 36V VIN = 42V ±1% 12.4 12.2 12.0 11.8 11.6 30137734 0.0 0.5 1.0 1.5 2.0 2.5 OUTPUT CURRENT (A) 3.0 30137738 LMZ14203H Transient Response 30% to 100% Load Step LMZ14203H Current Limit DC CURRENT LIMIT LEVEL (A) 6.0 5.5 5.0 4.5 4.0 Fsw = 250kHz Fsw = 400kHz Fsw = 600kHz 3.5 3.0 5 30137718 10 15 20 25 30 35 INPUT VOLTAGE (V) 40 45 30137741 LMZ14202H Current Limit LMZ14201H Current Limit 3.5 DC CURRENT LIMIT LEVEL (A) DC CURRENT LIMIT LEVEL (A) 4.5 4.0 3.5 3.0 Fsw = 250kHz Fsw = 400kHz Fsw = 600kHz 2.5 2.0 2.5 2.0 Fsw = 250kHz Fsw = 400kHz Fsw = 600kHz 1.5 1.0 5 10 15 20 25 30 35 INPUT VOLTAGE (V) 40 45 5 30137744 www.national.com 3.0 10 15 20 25 30 35 INPUT VOLTAGE (V) 40 45 30137747 4 LMZ14203H Conducted EMI, IOUT = 3A with 3.3µH 2x10µF LC line filter added Radiated Emissions EN 55022 Limit (Class B) 70 80 CONDUCTED EMISSIONS (dBμV) RADIATED EMISSIONS (dBμV/m) 80 60 50 40 30 20 10 0 0 200 400 600 800 FREQUENCY (MHz) AN-2089 LMZ14203H Radiated EMI, IOUT = 3A 70 Conducted Emissions CISPR 22 Quasi Peak CISPR 22 Average 60 50 40 30 20 10 0 1000 0.1 1 10 FREQUENCY (MHz) 100 30137748 30137751 LMZ14202H Radiated EMI, IOUT = 2A Radiated Emissions EN 55022 Limit (Class B) 70 80 CONDUCTED EMISSIONS (dBμV) RADIATED EMISSIONS (dBμV/m) 80 LMZ14202H Conducted EMI, IOUT = 2A with 3.3µH 2x10µF LC line filter added 60 50 40 30 20 10 0 0 200 400 600 800 FREQUENCY (MHz) 70 Conducted Emissions CISPR 22 Quasi Peak CISPR 22 Average 60 50 40 30 20 10 0 1000 0.1 1 10 FREQUENCY (MHz) 100 30137749 30137752 LMZ14201H Radiated EMI, IOUT = 1A Radiated Emissions EN 55022 Limit (Class B) 70 80 CONDUCTED EMISSIONS (dBμV) RADIATED EMISSIONS (dBμV/m) 80 LMZ14201H Conducted EMI, IOUT = 1A with 3.3µH 1µF LC line filter added 60 50 40 30 20 10 0 0 200 400 600 800 FREQUENCY (MHz) 70 Conducted Emissions CISPR 22 Quasi Peak CISPR 22 Average 60 50 40 30 20 10 0 1000 0.1 1 10 FREQUENCY (MHz) 100 30137750 30137753 5 www.national.com AN-2089 PCB Layout Diagrams Gerber and CAD files can be download from the LMZ14203H product folder. 30137709 FIGURE 2. Top Layer 30137710 FIGURE 3. Internal Layer I (Ground) Heat Sinking Layer www.national.com 6 AN-2089 30137711 FIGURE 4. Internal Layer II (Ground) Heat Sinking Layer 30137712 FIGURE 5. Bottom Layer (Ground and Routing) Heat Sinking Layer 7 www.national.com AN-2089 PCB Schematic 30137713 FIGURE 6. Detailed Schematic DNS = Component not installed 30137754 FIGURE 7. Conducted EMI LC Filter Configuration www.national.com 8 AN-2089 9 www.national.com LMZ14203H/02H/01H Evaluation Board Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Design Support Amplifiers www.national.com/amplifiers WEBENCH® Tools www.national.com/webench Audio www.national.com/audio App Notes www.national.com/appnotes Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns Data Converters www.national.com/adc Samples www.national.com/samples Interface www.national.com/interface Eval Boards www.national.com/evalboards LVDS www.national.com/lvds Packaging www.national.com/packaging Power Management www.national.com/power Green Compliance www.national.com/quality/green Switching Regulators www.national.com/switchers Distributors www.national.com/contacts LDOs www.national.com/ldo Quality and Reliability www.national.com/quality LED Lighting www.national.com/led Feedback/Support www.national.com/feedback Voltage References www.national.com/vref Design Made Easy www.national.com/easy www.national.com/powerwise Applications & Markets www.national.com/solutions Mil/Aero www.national.com/milaero PowerWise® Solutions Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors SolarMagic™ www.national.com/solarmagic PLL/VCO www.national.com/wireless www.national.com/training PowerWise® Design University THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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