LMR12020XSDEVM/NOPB

www.ti.com Table of Contents User’s Guide LMR12020 Step-Down Converter Evaluation Module User's Guide Table of Contents 1 Introduction.............................................................................................................................................................................2 2 Features...................................................................................................................................................................................2 3 Evaluation Module Schematic............................................................................................................................................... 2 4 Powering and Loading Considerations................................................................................................................................ 3 4.1 Quick Start Procedure........................................................................................................................................................3 4.2 Starting Up......................................................................................................................................................................... 3 4.3 Synchronization..................................................................................................................................................................3 4.4 No Load Start-Up at High Output Voltage.......................................................................................................................... 3 4.5 Adjusting the Output Voltage..............................................................................................................................................3 4.6 Typical Test Setup.............................................................................................................................................................. 3 5 Board Images.......................................................................................................................................................................... 6 6 Performance Characteristics.................................................................................................................................................8 7 Bill of Materials..................................................................................................................................................................... 10 8 PCB Layout............................................................................................................................................................................11 9 Revision History................................................................................................................................................................... 13 List of Figures Figure 3-1. LMR12020 Evaluation Module Schematic................................................................................................................ 2 Figure 4-1. Efficiency Measurements.......................................................................................................................................... 4 Figure 4-2. Voltage Ripple Measurements.................................................................................................................................. 4 Figure 4-3. Edge Connector Schematic.......................................................................................................................................5 Figure 5-1. Top Side.................................................................................................................................................................... 6 Figure 5-2. Bottom Side...............................................................................................................................................................7 Figure 6-1. Efficiency vs. Load Current LMR12020 VOUT = 5 V.................................................................................................. 8 Figure 6-2. Efficiency vs. Load Current LMR12020 VOUT = 3.3 V............................................................................................... 8 Figure 6-3. Load Transient Waveforms LMR12020, VOUT = 5 V, VIN = 12 V, IOUT = 200 mA to 2 A............................................8 Figure 6-4. Load Transient Waveforms LMR12020, VOUT = 3.3 V, VIN = 12 V, IOUT = 200 mA to 2 A.........................................8 Figure 6-5. Start-Up Waveform, VOUT = 3.3 V............................................................................................................................. 8 Figure 6-6. Start-Up Waveform, VOUT = 5 V................................................................................................................................ 8 Figure 6-7. Switching Node and Output Voltage Waveforms VIN = 12 V, IOUT = 2 A................................................................... 9 Figure 8-1. Top Copper.............................................................................................................................................................. 11 Figure 8-2. Top Overlay..............................................................................................................................................................11 Figure 8-3. Internal Layer 1....................................................................................................................................................... 12 Figure 8-4. Internal Layer 2....................................................................................................................................................... 12 Figure 8-5. Bottom Copper........................................................................................................................................................ 13 Figure 8-6. Bottom Overlay........................................................................................................................................................13 List of Tables Trademarks All trademarks are the property of their respective owners. SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 LMR12020 Step-Down Converter Evaluation Module User's Guide Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated 1 Introduction www.ti.com 1 Introduction The LMR12020 evaluation module is designed to provide the power supply design engineer with a fully functional regulator design, which can be synchronized to an external clock between 1000 kHz and 2350 kHz. The evaluation module provides two output voltage options viz. 3.3 V and 5 V with a 2-A current capability. Without an external synchronization signal, the design operates at 2000 kHz, reducing the solution size and keeping switching noise out of the AM radio band. The PCB consists of four layers of copper on FR4 material. The first middle layer is a solid ground layer, which helps in minimizing the AC current loop. The LMR12020 is thermally tied to the other layers by thermal vias directly underneath the device. This user's guide contains the evaluation module schematic, a quick setup procedure, and a bill-of-materials (BOM). For complete circuit design information, see the LMR12015/LMR12020 SIMPLE SWITCHER 20Vin, 1.5A/2A Step-Down Voltage Regulator in WSON-10 Data Sheet. 2 Features Parameter 3.3-V Output Voltage Option 5-V Output Voltage Option Input range 5 V to 20 V 7 V to 20 V Output voltage 3.3 V 5V Output current 0 A to 2 A 0 A to 2 A Frequency of operation 1000 kHz to 2350 kHz 1000 KHz to 2350 KHz Default frequency of operation 2000 kHz 2000 kHz Board size 1.944 × 1.35 inches (49.37 × 34.29 mm) 1.944 × 1.35 inches (49.37 × 34.29 mm) 3 Evaluation Module Schematic VIN 10 PVIN 9 PVIN 8 AVIN Cboost LMR12020XSD SW L1 VOUT 1 SW 2 SW Ren Co1 D1 J1 Co2 Cff Cin EN 4 EN Rfbt1 5 FB Rfbt2 Rdload DAP GND SYNC GND 6 R_S Rfbb GND Figure 3-1. LMR12020 Evaluation Module Schematic 2 LMR12020 Step-Down Converter Evaluation Module User's Guide SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated www.ti.com Powering and Loading Considerations 4 Powering and Loading Considerations Read this entire section prior to attempting to power the evaluation board. 4.1 Quick Start Procedure Step 1: Set the bench power supply current limit to 2 A. Set the power supply voltage to 12 V. Turn off the power supply output. Connect the power supply to the LMR12020 demo board. Positive connection to VIN and negative connection to GND Step 2: Connect a load, as high as 2 A, to the VOUT terminal. Positive connection to VOUT and negative connection to GND Step 3: Turn on the bench power supply with no load applied to the LMR12020 and the shunt for the jumper J1 in place. The VOUT would be in regulation at a nominal 3.3-V output. With the shunt out, a minimum load of 10 mA would be required to have the VOUT in regulation at 5 V. Step 4: Gradually increase the load and VOUT should remain in regulation as the load is increased up to 2 Amps. The VOUT should also be regulated when the input is swept from the minimum input to 20 V. 4.2 Starting Up The EN pin is tied to VIN to simplify start-up. The pullup resistor allows the power supply design engineer to toggle EN independently, if desired, and observe the start-up behavior of the LMR12020. Use the EN post to disable the device by pulling this node to GND. A logic signal can be applied to the post to test start-up and shutdown of the device. 4.3 Synchronization A SYNC pin has been provided on the evaluation board. This pin can be used to synchronize the regulator to an external clock or multiple evaluation boards can be synchronized together by connecting their SYNC pins together. For complete information, see the LMR12015/LMR12020 SIMPLE SWITCHER 20Vin, 1.5A/2A Step-Down Voltage Regulator in WSON-10 Data Sheet. 4.4 No Load Start-Up at High Output Voltage The LMR12020 cannot start-up at no load when the output voltage goes above 3.3 V. Refer to the LMR12020 data sheet for more information regarding minimum load requirements. A position for a dummy load is provided on the board. Populating that with a 500-Ω resistor facilitates the start-up at no load for the 5-V output voltage options. 4.5 Adjusting the Output Voltage The output voltage is set using the following equation where Rfbb is connected between the FB pin and GND, and Rfbt is connected between VOUT and FB. VOUT = VFB(1 + (Rfbt/Rfbb)) (1) Adjusting the output voltage will affect the performance of the LMR12020. In addition, output capacitors might not be rated for the new output voltage. For more information, see the LMR12015/LMR12020 SIMPLE SWITCHER 20Vin, 1.5A/2A Step-Down Voltage Regulator in WSON-10 Data Sheet. 4.6 Typical Test Setup SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 LMR12020 Step-Down Converter Evaluation Module User's Guide Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated 3 Powering and Loading Considerations www.ti.com Figure 4-1. Efficiency Measurements Oscilloscope VOUT GND Co2 Figure 4-2. Voltage Ripple Measurements 4 LMR12020 Step-Down Converter Evaluation Module User's Guide SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated www.ti.com Powering and Loading Considerations I I I I I 1 2 3 4 5 6 A B C D E F EN VIN VIN SENSE+ SPARE GND VOUT SENSE - VOUT VOUT SENSE+ GND I I I I I I I Figure 4-3. Edge Connector Schematic SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 LMR12020 Step-Down Converter Evaluation Module User's Guide Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated 5 Board Images www.ti.com 5 Board Images Figure 5-1. Top Side 6 LMR12020 Step-Down Converter Evaluation Module User's Guide SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated www.ti.com Board Images Figure 5-2. Bottom Side SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 LMR12020 Step-Down Converter Evaluation Module User's Guide Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated 7 Performance Characteristics www.ti.com 100 95 94 90 88 85 82 76 70 Vin = 7V Vin = 8V Vin = 10V Vin = 12V Vin = 14V Vin = 16V Vin = 18V Vin = 20V 64 58 52 46 40 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 IOUT(A) Figure 6-1. Efficiency vs. Load Current LMR12020 VOUT = 5 V EFFICIENCY (%) EFFICIENCY (%) 6 Performance Characteristics 80 75 70 Vin = 5V Vin = 7V Vin = 9V Vin = 12V Vin = 14V Vin = 16V Vin = 18V Vin = 20 65 60 55 50 45 0.0 0.3 0.6 0.9 1.2 IOUT(A) 1.5 1.8 2.1 Figure 6-2. Efficiency vs. Load Current LMR12020 VOUT = 3.3 V IOUT 1A/Div VOUT = 5V 50 mV/Div IOUT VOUT = 3.3V 50 mV/Div 500 mA/Div 100 Ps/DIV 100 Ps/DIV Figure 6-3. Load Transient Waveforms LMR12020, VOUT = 5 V, VIN = 12 V, IOUT = 200 mA to 2 A Figure 6-4. Load Transient Waveforms LMR12020, VOUT = 3.3 V, VIN = 12 V, IOUT = 200 mA to 2 A VIN = 20V VIN = 7V 5V/Div 5V/Div VOUT = 3.3V 1V/Div 8 VOUT = 5V 1V/Div IOUT = 2A IOUT = 2A 0.5A/Div 0.5A/Div 200 Ps/DIV 200 Ps/DIV Figure 6-5. Start-Up Waveform, VOUT = 3.3 V Figure 6-6. Start-Up Waveform, VOUT = 5 V LMR12020 Step-Down Converter Evaluation Module User's Guide SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated www.ti.com Performance Characteristics VOUT = 3.3V 50 mV/Div VSW 5V/Div 2 Ps/DIV Figure 6-7. Switching Node and Output Voltage Waveforms VIN = 12 V, IOUT = 2 A SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 LMR12020 Step-Down Converter Evaluation Module User's Guide Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated 9 Bill of Materials www.ti.com 7 Bill of Materials Part Name Part ID Part Value Part Number Manufacturer Buck Regulator U1 2-A Buck Regulator LMR12020 Texas Instruments Input Capacitor Cin 10 µF C1210C106K8PACTU Kemet Bootstrap Capacitor Cboost 0.1 µF C0603C104K8RACTU Kemet Output Capacitor Co1 22 µF GRM32ER71C226KE18L Murata Output Capacitor Co2 22 µF GRM32ER71C226KE18L Murata Catch Diode D1 Schottky Diode Vf = 0.32 V CMS01 Toshiba Inductor L1 3.3 µH 7447789003 Wurth Elektronik eiSos Feedback Resistor Rfbt1 4.02 kΩ CRCW06034K02FKEA Vishay-Dale Feedback Resistor Rfbt2 5.49 kΩ CRCW06035K49FKEA Vishay-Dale Feedback Resistor Rfbb 1.02 kΩ CRCW06031K02FKEA Vishay-Dale Pull-up Resistor Ren 4.75 kΩ CRCW06034K75FKEA Vishay-Dale Pull-down Resistor R_S 4.75 kΩ CRCW06034K75FKEA Vishay-Dale Test Point VIN Test Point Loop 5010 Keystone Test Point SW Test Point Loop 5012 Keystone Test Point GND Test Point Loop 5011 Keystone Test Point GND Test Point Loop 5011 Keystone Test Point VOUT Test Point Loop 5013 Keystone Test Point EN Test Point Loop 5014 Keystone Test Point SYNC Test Point Loop 5014 Keystone Header J1 2 × 1 Header, TH, 100mil TSW-102-07-G-S Samtec, Inc. Shunt SH-J1 Black 100-mil Gold Plated Shunt 969102-0000-DA 3M 10 LMR12020 Step-Down Converter Evaluation Module User's Guide SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated www.ti.com PCB Layout 8 PCB Layout Figure 8-1. Top Copper Figure 8-2. Top Overlay SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 LMR12020 Step-Down Converter Evaluation Module User's Guide Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated 11 PCB Layout www.ti.com Figure 8-3. Internal Layer 1 Figure 8-4. Internal Layer 2 12 LMR12020 Step-Down Converter Evaluation Module User's Guide SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated www.ti.com Revision History Figure 8-5. Bottom Copper Figure 8-6. Bottom Overlay 9 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision A (April 2013) to Revision B (December 2021) Page • Updated the numbering format for tables, figures, and cross-references throughout the document. ................2 SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 LMR12020 Step-Down Converter Evaluation Module User's Guide Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated 13 Revision History • • 14 www.ti.com Updated the user's guide title............................................................................................................................. 2 Edited user's guide for clarity..............................................................................................................................2 LMR12020 Step-Down Converter Evaluation Module User's Guide SNVU191B – OCTOBER 2012 – REVISED DECEMBER 2021 Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated IMPORTANT NOTICE AND DISCLAIMER TI PROVIDES TECHNICAL AND RELIABILITY DATA (INCLUDING DATA SHEETS), DESIGN RESOURCES (INCLUDING REFERENCE DESIGNS), APPLICATION OR OTHER DESIGN ADVICE, WEB TOOLS, SAFETY INFORMATION, AND OTHER RESOURCES “AS IS” AND WITH ALL FAULTS, AND DISCLAIMS ALL WARRANTIES, EXPRESS AND IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS. 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