EVK User's Manual ROHM Switching Regulator Solutions Evaluation Board: Synchronous Buck Converter Integrated FET BD9B301MUV-EVK-101 (3.3 | 3A Output) Introduction This application note will provide the steps necessary to operate An EN pin allows for simple ON/OFF control of the IC to reduce and evaluate ROHM's synchronous buck DC/DC converter standby current consumption, while a MODE pin enables users using the BD9B301MUV-EVK-101 evaluation board. Component to select Fixed Frequency PWM mode or Deep SLLM control that selection, board layout recommendations, operating procedures, automatically switches between modes. and application data are provided. Applications Description * Step-Down Power Supplies for DSPs, FPGAs, Microcontrollers, and more This evaluation board has been specifically developed to evaluate * Laptop PCs/Tablet PCs/Servers ROHM's BD9B301MUV synchronous buck DC/DC converter with * LCD TVs * Storage Devices (HDDs/SSDs) integrated 32m Pch high-side and Nch low-side MOSFETs. * Printers, OA Equipment Features include 3.3V output from 2.7V to 5.5V input and variable * Entertainment Devices switching frequency: 1MHz (FREQ pin connected to VIN) or 2MHz * Distributed and Secondary Power Supplies (FREQ pin connected to Ground). Multiple protection cricuits are also buil in, including a fixed soft start circuit that prevents inrush current during startup, UVLO (Under Voltage Lock Out), and TSD (Thermal Shutdown). Evaluation Board Operating Limits and Absolute Maximum Ratings Parameter Symbol Limit Unit MIN TYP MAX VCC 2.7 5.5 V VOUT 3.3 V IOUT 3 A Conditions Supply Voltage BD9B301MUV Output Voltage/Current BD9B301MUV (c) 2017 ROHM CO., Ltd. 1 No. 60UG024E Rev.001 OCT 2017 Eval Board: Synchronous Buck Converter Integrated FET EVK User's Manual Evaluation Board Figure 1: Evaluation Board for the BD9B301MUV Board Schematic VOUT R1 140 5% 1/10W 0603 PGD_LED CR1 SML-310MTT86 LED_0603 PGD_QC AVIN VIN AVIN R2 100k 5% 1/10W 0603 R3 0603 TP1 (INPUT: 2.7-5.5 VDC) VIN TP2 D1 P48MA6.8A DO-214A/C 5.8V 39.0A TP3 AVIN 1 1 2 AVIN C2 0.1F 16 10% 16V C3 0603 0.1F 10% 16V 0603 5 C1 10F 10% 10V 1206 J1 3 87224-3 J2 1 3 2 3 4 EN FREQ SS 2 3 PVIN PVIN AVIN PGD SW SW SW 14 PGD 10 SW 11 12 AGND PGND PGND EN FREG MODE SS BOOT FB 13 BOOT C4 0.1F 10% 16V 0603 1.5H 20% 8A 1k PGD_QB B 5% 1/10W Q1 SST2222AT116 SOT23 (OUTPUT: 3.3V@3A) VOUT L1 74437349015 SMT_6P6x6P6 R4 160k 1% 1/10W 0603 C10 180pF 5% 50V 0603 C5 22F 10% 6.3V 1210 C6 22F 10% 6.3V 1210 TP4 C7 0603 DNP C8 0805 DNP C9 1206 DNP TP5 6 FB R5 51k 1% 1/10W 0603 EPAD 17 VOUT=0.8*(R4+R5)/R5 C11 0603 DNP 87224-3 J3 1 15 7 8 9 U1 BD9B301MUV VQFND16V3030 2 MODE 87224-3 BD9B301MUV EVM Jumper Positions Reference Designator J1 J2 J3 Position Description Note: 1. 0.8V=< VOUT =V 0.8*VIN 2-1 Enable U1 2-3 Disable U1 2-1 Set switching frequency of U1 is 1.0MHz 2-3 Set switching frequency of U1 is 2.0MHz 2-1 Set operation mode of U1 is fixed frequency PWM mode 2-3 Set operation mode of U1 is automatically switched between the Deep-SLLM control and fixed frequency PWM mode Figure 2: BD9B301MUV-EVK-101 Evaluation Board Schematic (c) 2017 ROHM CO., Ltd. 2 No. 60UG024E Rev.001 OCT 2017 Eval Board: Synchronous Buck Converter Integrated FET EVK User's Manual Board I/O Below is a reference application circuit that shows the inputs VIN, Enable, FREQ and MODE and the output VOUT. BD9B301MUV VIN AVIN Enable 10F PGD PGD PVIN BOOT EN CBOOT 0.1F VOUT SW AGND 1.0H PGND R1 SS CSS MODE MODE FREQ FREQ CFB 22F x 2 FB R2 Figure 2: BD9B301MUV-EVK-101 Evaluation Board I/O Operating Procedure 1. Connect the power supply's GND terminal to GND test point TP3 on the evaluation board. 2. Connect the power supply's VCC terminal to VIN test point TP2 on the evaluation board. This will provide VIN to the IC U1. Please note that VCC should be in the range from 2.7V to 5.5V. 3. Set the operating mode by changing the position of shunt jumper J3 (If Pin2 is connected to Pin1, the MODE pin of IC U1 will be pulled high and IC U1 will operate in Fixed frequency PWM mode, otherwise the MODE pin of IC U1 will be pulled low and IC U1 will operate by automatically switching between Deep-SLLM control and fixed frequency PWM mode). 4. Set the switching frequency by changing the position of shunt jumper J2 (If Pin2 is connected to Pin1, the FREQ pin of IC U1 will be pulled high and IC U1 will switch frequency to 1.0MHz, otherwise the FREQ pin of IC U1 will be pulled low and the the frequency will be switched to 2.0MHz). 5. Check if shunt jumper J1 is the ON position (Connect Pin 2 to Pin 1, the EN pin of IC U1 is pulled high as a default). 6. Connect the electronic load to TP4 and TP5. Do not turn on the load. 7. Turn on the power supply. The output voltage VOUT (+3.3V) can be measured at the test point TP4. Now turn on the load. The load can be increased up to 3A MAX. (c) 2017 ROHM CO., Ltd. 3 No. 60UG024E Rev.001 OCT 2017 Eval Board: Synchronous Buck Converter Integrated FET EVK User's Manual Reference Application Data The following are graphs of the hot plugging test, quiescent current, efficiency, load response, and output voltage ripple response of the BD9B301MUV-EVK-101 evaluation board. Fig 4: Hot Plug-in Test with Zener Diode P4SMA6.8A, VIN=5.5V, VOUT=3.3V, IOUT=3A, FREQ=L, MODE=L Fig 5: Circuit Current vs. Power Supply Voltage Characteristics (Temp=25C, FREQ=L, MODE=L) Fig 6: Electric Power Conversion Rate (VOUT=3.3V, FREQ=L, MODE=L) Fig 7: Load Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=0 3A, FREQ=L, MODE=L) Fig 8: Load Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=3A 0, FREQ=L, MODE=L) Fig 9: Output Voltage Ripple Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=0, FREQ=L, MODE=L) Fig 10: Output Voltage Ripple Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=3A, FREQ=L, MODE=L) (c) 2017 ROHM CO., Ltd. 4 No. 60UG024E Rev.001 OCT 2017 Eval Board: Synchronous Buck Converter Integrated FET EVK User's Manual Typical Performance Data - continued Fig 11: Hot Plug-in Test with Zener Diode P4SMA6.8A, VIN=5.5V, VOUT=3.3V, IOUT=3A, FREQ=L, MODE=H Fig 12: Circuit Current vs. Power Supply Voltage Characteristics (Temp=25C, FREQ=L, MODE=H) Fig 13: Electric Power Conversion Rate (VOUT=3.3V, FREQ=L, MODE=H) Fig 14: Load Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=0 3A, FREQ=L, MODE=H) Fig 15: Load Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=3A 0, FREQ=L, MODE=H) Fig 16: Output Voltage Ripple Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=0, FREQ=L, MODE=H) Fig 17: Output Voltage Ripple Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=3A, FREQ=L, MODE=H) (c) 2017 ROHM CO., Ltd. 5 No. 60UG024E Rev.001 OCT 2017 Eval Board: Synchronous Buck Converter Integrated FET EVK User's Manual Typical Performance Data - continued Fig 18: Hot Plug-in Test with Zener Diode P4SMA6.8A, VIN=5.5V, VOUT=3.3V, IOUT=3A, FREQ=H, MODE=L Fig 19: Circuit Current vs. Power Supply Voltage Characteristics (Temp=25C, FREQ=H, MODE=L) Fig 20: Electric Power Conversion Rate (VOUT=3.3V, FREQ=H, MODE=L) Fig 21: Load Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=0 3A, FREQ=H, MODE=L) Fig 22: Load Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=3A 0, FREQ=H, MODE=L) Fig 23: Output Voltage Ripple Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=0, FREQ=H, MODE=L) Fig 24: Output Voltage Ripple Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=3A, FREQ=H, MODE=L) (c) 2017 ROHM CO., Ltd. 6 No. 60UG024E Rev.001 OCT 2017 Eval Board: Synchronous Buck Converter Integrated FET EVK User's Manual Typical Performance Data - continued Fig 25: Hot Plug-in Test with Zener Diode P4SMA6.8A, VIN=5.5V, VOUT=3.3V, IOUT=3A, FREQ=H, MODE=H Fig 26: Circuit Current vs. Power Supply Voltage Characteristics (Temp=25C, FREQ=H, MODE=H) Fig 27: Electric Power Conversion Rate (VOUT=3.3V, FREQ=H, MODE=H) Fig 28: Load Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=0 3A, FREQ=H, MODE=H) Fig 29: Load Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=3A 0, FREQ=H, MODE=H) Fig 30: Output Voltage Ripple Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=0, FREQ=H, MODE=H) Fig 31: Output Voltage Ripple Response Characteristics (VIN=5V, VOUT=3.3V, IOUT=3A, FREQ=H, MODE=H) (c) 2017 ROHM CO., Ltd. 7 No. 60UG024E Rev.001 OCT 2017 Eval Board: Synchronous Buck Converter Integrated FET EVK User's Manual Evaluation Board Layout Guidelines In the step-down DC/DC converter, a large pulse current flows through two loops. The first loop is the one into which current flows when the High-Side FET is turned ON. The flow starts from the input capacitor CIN, runs through the FET, inductor L, and output capacitor COUT, then back to the GND of CIN via the GND of COUT. In the second loop current flows when the Low-Side FET is turned on. The flow starts from the Low-Side FET, runs through the inductor L and output capacitor COUT, then back to the GND of the LowSide FET via the GND of COUT. We recommend routing these two loops as thick and as short as possible to minimize noise and improve efficiency. The input and output capacitors should be connected directly to the GND plane. Please note that the PCB layout has a large influence on the DC/DC converter in terms of heat generation, noise, and efficiency. VIN MOSFET CIN VOUT L COUT Fig 32: Current Loops of Buck Regulator System Accordingly, when designing the PCB layout please consider the following points. * Connect an input capacitor as close as possible to the IC PVIN terminal on the same plane as the IC. * If there is any unused area on the PCB, provide a copper foil plane for the GND node to assist heat dissipation from the IC and the surrounding components. * Switching nodes such as SW are susceptible to noise due to AC coupling with other nodes. Therefore, route the coil pattern as thick and as short as possible. * Ensure that lines connected to FB are far from the SW nodes. * Place the output capacitor away from the input capacitor in order to avoid the effects of harmonic noise from the input. Power Dissipation When designing the PCB layout and peripheral circuitry, sufficient consideration must be given to ensure that the power dissipation is within the allowable dissipation curve. 1. 4-layer board (surface heat dissipation copper foil 5505 mm2) (Copper foil laminated on each layer) JA= 47.0C/W 2. 4-layer board (surface heat dissipation copper foil 6.28 mm2) (Copper foil laminated on each layer) JA= 70.62C/W 3. 1-layer board (surface heat dissipation copper foil 6.28 mm2) JA= 201.6C/W 4. IC only JA= 462.9C/W Fig 33: Thermal Derating Characteristics (c) 2017 ROHM CO., Ltd. 8 No. 60UG024E Rev.001 OCT 2017 Eval Board: Synchronous Buck Converter Integrated FET EVK User's Manual Fig 34: BD9B301MUV-EVK-101 Board PCB layout Application Circuit Component Selection Inductor (L) The inductance significantly depends on the output ripple current. As shown by following equation, the ripple current decreases as the inductor and/or switching frequency increases. IL = (VIN -VOUT) x VOUT L x VIN x f (V -V ) x VOUT L x VbeINequal x f to the maximum load current plus half of the inductor As a minimum requirement, the DC current rating of the inductor should L I ripple current as shown by the equation below. ILPEAK = IOUTMAX + 2 INRippleOUT Where f=Switching Frequency, L=Inductance, and L=Inductor Current. IL = ILPEAK = IOUTMAX + (c) 2017 ROHM CO., Ltd. 9 IL 2 No. 60UG024E Rev.001 OCT 2017 Eval Board: Synchronous Buck Converter Integrated FET EVK User's Manual Evaluation Board BOM Below is a table showing the bill of materials. Part numbers and supplier references are also provided. No. Qty. Reference Description Manufacturer Part No. 1 1 CR1 LED 570NM GREEN WTR CLR 0603 SMD ROHM SML-310MTT86 2 1 C1 CAP CER 10F 10V 10% X5R 1206 Murata GRM319R61A106KE19D 3 3 C2, C3, C4 CAP CER 0.1F 16V 10% X7R 0603 Murata GRM188R71C104KA01D 4 2 C5, C6 CAP CER 22F 6.3V 10% X5R 1210 Murata GRM32DR60J226KA01L 5 1 C10 CAP CER 180PF 50V 5% NP0 0603 Murata GRM1885C1H181JA01D 6 1 D1 DIODE TVS 400W 6.8V UNI 5% SMD 7 3 J1, J2, J3 CONN HEADER VERT .100 3POS 15AU 8 1 L1 INDUCTOR WW 1.5H 8A SMD Wurth 74437349015 Littlefuse Inc. TE Connectivity P4SMA6.8A 87224-3 9 1 Q1 TRANSISTOR NPN 40V 0.6A SOT-23 ROHM SST2222AT116 10 1 R1 RES 140 OHM 1/10W 1% 0603 SMD ROHM MCR03ERTF1400 11 1 R2 RES 100K OHM 1/10W 5% 0603 SMD ROHM MCR03ERTJ104 12 1 R3 RES 1K OHM 1/10W 5% 0603 SMD ROHM MCR03ERTJ102 13 1 R4 RES 160K OHM 1/10W 1% 0603 SMD ROHM MCR03ERTF1603 14 1 R5 RES 51K OHM 1/10W 1% 0603 SMD ROHM MCR03ERTF5102 15 3 TP1, TP2, TP4 TEST POINT PC MULTI PURPOSE RED Keystone Electronics 5010 16 2 TP3, TP5 TEST POINT PC MULTI PURPOSE BLK Keystone Electronics 5011 17 1 U1 DCDC Converter 18 3 (c) 2017 ROHM CO., Ltd. ROHM Shunt jumper for header J1, J2, J3 (item #7), CONN SHUNT 2POS GOLD W/HANDLE 10 TE Connectivity BD9B301MUV 881545-1 No. 60UG024E Rev.001 OCT 2017 Notice Notes 1. The information contained herein is subject to change without notice. 2. Before you use our Products, please contact a sales representative and verify the latest specifications. 3. Although ROHM is continuously working to improve product reliability and quality, semiconductors can break down and malfunction due to various factors. Therefore, in order to prevent personal injury or fire arising from failure, please take safety measures such as complying with the derating characteristics, implementing redundant and fire prevention designs, and utilizing backups and fail-safe procedures. ROHM shall have no responsibility for any damages arising out of the use of our Poducts beyond the rating specified by ROHM. 4. Examples of application circuits, circuit constants and any other information contained herein are provided only to illustrate the standard usage and operations of the Products. The peripheral conditions must be taken into account when designing circuits for mass production. 5. The technical information specified herein is intended only to show the typical functions and examples of application circuits for the Products. ROHM does not grant you, explicitly or implicitly, any license to use or exercise intellectual property or other rights held by ROHM or any other parties. ROHM shall have no responsibility whatsoever for any dispute arising out of the use of such technical information. 6. The Products specified in this document are not designed to be radiation tolerant. 7. When using our Products in applications requiring a high degree of reliability (as exemplified below), please contact and consult with a ROHM representative : transportation equipment (i.e. cars, ships, trains), primary communication equipment, traffic lights, fire/crime prevention, safety equipment, medical systems, servers, solar cells, and power transmission systems. 8. Do not use our Products in applications requiring extremely high reliability, such as aerospace equipment, nuclear power control systems, and submarine repeaters. 9. ROHM shall bear no responsibility for any damages or injury arising from non-compliance with the recommended usage conditions and specifications contained herein. 10. ROHM has used reasonable care to ensure the accuracy of the information contained in this document. However, ROHM does not warrants that such information is error-free, and ROHM shall have no responsibility for any damages arising from any inaccuracy or misprint of such information. 11. Please use the Products in accordance with any applicable environmental laws and regulations, such as the RoHS Directive. For more details, including RoHS compatibility, please contact a ROHM sales office. ROHM shall bear no responsibility for any damages or losses resulting from non-compliance with any applicable laws or regulations. 12. When providing our Products and technologies contained in this document to other countries, you must abide by the procedures and provisions stipulated in all applicable export laws and regulations, including without limitation the US Export Administration Regulations and the Foreign Exchange and Foreign Trade Act. 13. This document, in part or in whole, may not be reprinted or reproduced without the prior consent of ROHM. Thank you for your interest in ROHM products. Please contact us for additional information and product catalogs. ROHM Customer Support System www.rohm.com/contact WWW.ROHM.COM (c) 2017 ROHM Co., Ltd. All rights reserved