LMZ23605

LMZ23605/03, LMZ22005/03 Evaluation Board LMZ23605/03, LMZ22005/03 Evaluation Board National Semiconductor Application Note 2085 Alan Martin March 27, 2011 Introduction The LMZ23605/03, LMZ22005/03 evaluation boards are designed to be an easy-to-use platform to evaluate the full capabilities of this family of SIMPLE SWITCHER® power modules. The PCB construction has excellent thermal performance and includes extra locations for optional components that may not be required in the end application. The LMZ23605/03 can accept an input voltage rail between 6V and 36V and the LMZ22005/03 can accept an input voltage rail between 6V and 20V. The devices can deliver an adjustable and highly accurate output voltage as low as 0.8V and as high as 6V. The control architecture is constant frequency PWM with emulated current mode sensing. The control loop operates well with low ESR output capacitors such as ceramics or specialty polymer. The precision enable input allows for programmable UVLO on the input supply or flexibility in sequencing. The external soft-start capacitor facilitates controlled output rise time at startup. The module family is a reliable and robust solution with cycle-by-cycle valley current limit to protect for over current or short-circuit faults. Additionally there is thermal shutdown protection, and they will start up into a pre-biased output. The free-running switching frequency is 812 kHz (typ) and a 650 kHz to 950 kHz synchronization range is supported. Board Specifications • • • • • • VIN = 6V to 36V (LMZ22005/03 limited to 20V) Enable UVLO = 5.7V VOUT = 3.3V IOUT = 0 to 5A (LMZ23603 and LMZ22003 limited to 3A) θJA = 12°C / W, θJC = 1.9°C/W PCB designed on four layers; Inner are 2 oz; Outer are 3 oz. • Measures 3.5 in. x 3.5 in. (8.9 cm x 8.9 cm) and is 62mil (.062”) thick of FR4 laminate material • Max ambient temp of 70°C at full 5A load (12 Vin) For additional circuit considerations refer to the Applications Section of the LMZ23605/03 or LMZ22005/03 data sheets. For negative output voltage connections follow the method shown in AN-2027. 30131601 FIGURE 1. Evaluation Board Simplified Schematic AN-2085 © 2011 National Semiconductor Corporation 301316 www.national.com AN-2085 Performance Characteristics LMZ23605 3.3Vout Efficiency @ 25°C Ambient 100 90 80 70 60 50 40 0 8 Vin 12 Vin 20 Vin 24 Vin 30 Vin 36 Vin 1 2 3 4 OUTPUT CURRENT (A) 5 30131637 LMZ23605 3.3Vout Dissipation @ 25°C Ambient 8 7 DISSIPATION (W) 6 5 4 3 2 1 0 0 1 2 3 4 OUTPUT CURRENT (A) 5 30131638 EFFICIENCY (%) 36 Vin 30 Vin 24 Vin 20 Vin 12 Vin 8 Vin LMZ23605 3.3Vout Efficiency @ 85°C 100 90 80 70 60 50 40 0 1 2 3 4 OUTPUT CURRENT (A) 9 Vin 12 Vin 20 Vin 24 Vin 30 Vin 36 Vin 5 30131630 LMZ23605 3.3Vout Dissipation @ 85°C 8 7 DISSIPATION (W) 6 5 4 3 2 1 0 0 1 2 3 4 OUTPUT CURRENT (A) 5 30131631 LMZ23605 Load and Line Regulation @ 25°C Ambient 1.002 EFFICIENCY (%) 36 Vin 30 Vin 24 Vin 20 Vin 12 Vin 9 Vin LMZ23605 Current Limit VOUT = 3.3V 8 7 OUTPUT VOLTAGE (V) 1.001 6 CURRENT (A) 5 4 3 2 1 5 30131636 Output Current 1.000 9 Vin 12 Vin 20 Vin 24 Vin 30 Vin 36 Vin 0 1 2 3 4 OUTPUT CURRENT (A) 0.999 Input Current 0.998 0 0 4 8 12 16 20 24 28 32 36 INPUT VOLTAGE (V) 30131639 www.national.com 2 AN-2085 Output Ripple VOUT = 3.3V IOUT = 5A, BW to 20 MHz Output Ripple VOUT = 3.3V IOUT = 5A, BW to 250 MHz 30131620 30131621 LMZ23605 Load Step Response VIN = 12V VOUT = 3.3V, 0.5A to 5A Step LMZ23603 Load Step Response VIN = 12V VOUT = 3.3V, 0.5A to 3A Step 30131618 30131619 LMZ23605 Start-up LMZ23605 Pre-biased startup 30131640 30131641 3 www.national.com AN-2085 Notes Solder turrets are located on the edge of the PCB assembly for evaluation hookup to bench test equipment. The Enable input turret is designed for direct connection to the VIN turret. There is a resistive divider implemented on the board that establishes the 5.5V precision UVLO level of the board. A common user change to this divider is to raise the value of RENT to increase the operating UVLO to that of the target application. Refer to the respective data sheet for calculation. Note that if in the end application the module pin 3 enable voltage does not exceed 5.5V at maximum Vin, then enable clamp zener D1 can be omitted. Each implementation of the evaluation board is preset to 3.3V output; with current rating and maximum input voltage rating dictated by the model of module installed. A common user change is to adjust the output voltage for different requirements. A table of suggested resistor pairs are listed in Figure 1 for quick reference. Locations are provide for testing the operation as a coincident turn-on tracking supply (slave). To implement this feature, remove CSS and install Rtkt and Rtkb. Calculations are suggested in the respective data sheets. A turret is also provided for applying a clock to synchronize the module switching frequency anywhere between 650 kHz and 950 kHz. Note that a sustained “logic one” on this input corresponds to “zero hertz” and will cause the module to stop switching. J1 and J2 are for input and output noise measurement. To implement this feature, populate the 1uF blocking capacitors and the 49.9 ohm source resistors. Install Amphenol coax connectors type 112404 (Digikey #ACX1051).The added RC network forms a 2X scope probe when used in conjunction with an input termination of 50 ohms at the oscilloscope, providing 5 times more sensitivity than a conventional 10x probe. J3 is for connection to a frequency response analyzer such as A/P Instruments (Ridley) or Venable Industries products. Refer to the FRA operating manual for this connection. Note: Do not place any type of shorting jumper to these three posts as that will cause a malfunction. Inductor current can be monitored by connecting a loop of between module pin 7 (Vout) and the Co array. First cut the top side conducting etch between the two vias adjacent to pin 7, then install a 5” loop of 22 ga insulated wire in the two vias. Monitor the inductor sense loop with an AC/DC oscilloscope current probe. The Vin input plane has solder mask openings where an input LC network can be placed to accommodate improved differential mode and conducted EMI performance. Additional component mounting pads are available to experiment with alternative Cin and Cout combinations. See Figure 6 for corresponding schematic locations. PCB View and layout diagrams Gerber and CAD files can be downloaded from the LMZ23605 /03, LMZ22005/03 respective product folders. 30131614 FIGURE 2. Top View of Assembly www.national.com 4 AN-2085 30131609 FIGURE 3. Top Layer 30131610 FIGURE 4. Internal Layer I (Ground) Heat Sinking Layer 5 www.national.com AN-2085 30131611 FIGURE 5. Internal Layer II (Ground and Routing) Heat Sinking Layer 30131612 FIGURE 6. Bottom Layer (Ground) Heat Sinking Layer www.national.com 6 AN-2085 30131613 FIGURE 7. LMZ2360x / LMZ2200x PCB CAD package schematic DNP = Component not populated 7 www.national.com AN-2085 TABLE 1. Bill of Materials, VIN = 6V to 36V, VOUT = 3.3V, IOUT (MAX) = 5A (3A) Note: The same BOM applies to all implementations Designator U1 Description SIMPLE SWITCHER® Case Size TO-PMOD-7 Manufacturer National Semiconductor Manufacturer P/N LMZ23605TZ or LMZ23603TZ or LMZ22005TZ or LMZ22003TZ CC1206KRX7R9BB473 Quantity 1 CIN1 CIN5 CO1 CO6 CIN2 CIN3 CIN6 OPT CO2 OPT CO5 CFF CSS D1 RENB RENT RENH RFBT RFBB RFRA RFF RSN 0.047 µF, X7R, 50V 1206 Yageo America 4 10 µF, X5R, 50V 150 µF,Aluminum Electrolytic, 50V 100 µF, X5R, 6.3V 220 µF, Specialty Polymer, 6.3V DNP 0.47µF, X7R, 16V 5.1V 200mW 12.7 kΩ 42.2 kΩ 100 Ω 3.32 kΩ 1.07 kΩ 23.7 Ω DNP 1.50 kΩ 1210 G 1210 Taiyo Yuden Panasonic TDK Panasonic UMK325BJ106MM-T EEE-FK1H151P C3225X5R0J107M EEF-UE0J221LR 2 1 1 1 0805 SOD-323 0805 0805 0805 0805 0805 0805 0805 AVX Diodes Inc. Panasonic Panasonic Vishay-Dale Vishay-Dale Vishay-Dale Vishay-Dale Vishay-Dale 0805YC474KAT2A MMSZ5231BS-7-F ERJ-6ENF1272V ERJ-6ENF4222V CRCW0805100RFKEA CRCW08053K32FKEA CRCW08051K07FKEA CRCW080523R7FKEA CRCW08051K50FKEA 1 1 1 1 1 1 1 1 1 www.national.com 8 AN-2085 9 www.national.com LMZ23605/03, LMZ22005/03 Evaluation Board 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-2085 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