ROHM BD9P108MUF DC Converter For Automotive Evaluation Board User Guide

ROHM BD9P108MUF DC Converter For Automotive Evaluation Board User Guide

Introduction

This user’s guide will provide the necessary steps to operate the Evaluation Board of ROHM’s BD9P108MUF-C Buck DC/DC converter. This includes the external parts, operating procedures and application data.

Description

This Evaluation Board was developed for ROHM’s single 2.2 MHz buck DC/DC converter BD9P108MUF-C. BD9P108MUFC is a current mode synchronous buck DC/DC converter with integrated POWER MOSFETs. The BD9P108MUF-C accepts a power supply input range of 3.5 V to 40 V and generates a maximum output current of 1 A. BD9P108MUF-C generates an output voltage range of 0.8 V to 8.5 V using external resistors

Application

Automotive Powered Supplies
Consumer Powered Supplies

Recommended Operating Conditions

Table 1. Recommended Operating Conditions

0.5 A (Max)
Switching Frequency| –| 2.2| –| MHz|
Maximum Efficiency| –| 85.8| –| %| VO = 3.3 V, Io = 0.5 A, Ta = 25 °C
Maximum Efficiency| –| 91.4| –| %| VO = 5.0 V, Io = 0.7 A, Ta = 25 °C

(Note1) Although the minimum output voltage is configurable up to 0.8 V, it may be limited by the SW min ON pulse width. For the same reason, although the maximum output voltage is configurable up to 8.5 V, it may be limited by the SW minimum OFF pulse width.

**Evaluation Board

Evaluation Board Schematic

**

Operating Procedure

1. Turn off EN and connect the GND terminal of the power supply to the GND terminal of Evaluation Board.
2. Connect VCC pin of power supply to the VBAT pin of the Evaluation Board.
3. Connect the load to the Evaluation Board’s VOUT and GND terminals. When using an electronic load, connect with the load turned off.
4. Connect a voltmeter to the Evaluation Board’s VOUT and GND terminals.
5. Turn on the Power supply of VBAT. Turn ON the switch of EN terminal.
6. Make sure that the voltmeter is set to measure voltage.
7. Turn on the electronic load.

(Caution) This Evaluation Board does not support hot plug. Do not perform hot plug test.
(Note) If EN=High (EN short to VIN) before Power ON, the turn ON and turn OFF is controlled by VBAT only

Operation Mode Settings

Below is a table of BD9P108MUF-C operation modes selectable using OCP_SEL, MODE and SSCG terminals.

Table 2. Mode Settings

(Typ.) Output Current maximum is 1 A.
LOW| OCP threshold is set to 0.625 A (Typ.) Output Current maximum is 0.5 A.
MODE| HIGH| FPWM| Forced PWM mode
LOW or OPEN| AUTO| Automatically switched between PWM and LLM mode.
Apply a clock to this pin| SYNC| Activate synchronization mode
SSCG| ON (HIGH)| Select Spread Spectrum function| Enable Spread Spectrum
OFF (LOW)| Disable Spread Spectrum

(Note) If setting is High, the terminal is shorted to VREG, and if setting is Low, the terminal is shorted to GND.

Pin Configuration

Figure 3. Pin Configuration (Top View)

Parts List (BD9P108MUF-C)

Table 3. Parts list (3.3 V, 1.0 A)

| Part No| Value| PKG(inch)| PKG(mm)| Manufacturer| Part Name(Series)
---|---|---|---|---|---|---
π type filter| CF1| 4.7μF| 1210| 3225| Murata| GCM32ER71H475K
CF3| Open| –| –| –| –
LF1| 2.2μH| 2524h18| 6360h45| TDK| CLF6045NIT-2R2N-D
CF2| 0.1μF| 0402| 1005| Murata| GCM155R71H104K
CBLK| 220μF| 0404h04| 1010h10| Nichicon| UWD1V221MCL1GS
Basic| CIN2| 4.7μF| 1210| 3225| Murata| GCM32ER71H475K
CIN1| 0.1μF| 0402| 1005| Murata| GCM155R71H104K
CIN1B| Open| –| –| –| –
CVREG| 1μF| 0805| 2012| Murata| GCM21BR71C105K
CBST| 0.1μF| 0402| 1005| Murata| GCM155R71H104K
RBST| 0Ω| 0402| 1005| ROHM| MCR01 Series
RSNB| Open| –| –| –| –
CSNB| Open| –| –| –| –
RRST| 10kΩ| 0402| 1005| ROHM| MCR01 Series
RRST2 (Note 3)| Open| –| –| –| –
Application| L1| 6.8μH| 2524h18| 6360h45| TDK| CLF6045NIT-6R8N-D
COUT1 to 4(Note 1)| 10μF x 3 (Mounted on Board)or| 1210| 3225| Murata| GCM32ER71E106K
22μF x 2or| 1210| 3225| Murata| GCM32ER71A226K
22μF x 3| 0805| 2012| Murata| GCM21BD70J226M
RFB0| 0Ω| 0402| 1005| ROHM| MCR01 Series
RFB1| 75kΩ| 0402| 1005| ROHM| MCR01 Series
RFB2| 24kΩ| 0402| 1005| ROHM| MCR01 Series
CFB1 (Note 4)| Open| –| –| –| –
CFB2 (Note 4)| Open| –| –| –| –
RDIS| 0Ω| 0402| 1005| ROHM| MCR01 Series
RDISN| Open| –| –| –| –
REX (Note 2)| 0Ω| 0402| 1005| ROHM| MCR01 Series
REXN (Note 2)| Open| –| –| –| –

Table 4. Parts list (5.0 V, 1.0 A)

| Part No| Value| PKG(inch)| PKG(mm)| Manufacturer| Part Name(Series)
---|---|---|---|---|---|---
π type filter| CF1| 4.7μF| 1210| 3225| Murata| GCM32ER71H475K
CF3| Open| –| –| –| –
LF1| 2.2μH| 2524h18| 6360h45| TDK| CLF6045NIT-2R2N-D
CF2| 0.1μF| 0402| 1005| Murata| GCM155R71H104K
CBLK| 220μF| 0404h04| 1010h10| Nichicon| UWD1V221MCL1GS
Basic| CIN2| 4.7μF| 1210| 3225| Murata| GCM32ER71H475K
CIN1| 0.1μF| 0402| 1005| Murata| GCM155R71H104K
CIN1B| Open| –| –| –| –
CVREG| 1μF| 0805| 2012| Murata| GCM21BR71C105K
CBST| 0.1μF| 0402| 1005| Murata| GCM155R71H104K
RBST| 0Ω| 0402| 1005| ROHM| MCR01 Series
RSNB| Open| –| –| –| –
CSNB| Open| –| –| –| –
RRST| 10kΩ| 0402| 1005| ROHM| MCR01 Series
RRST2 (Note 3)| Open| –| –| –| –
Application| L1| 6.8μH| 2524h18| 6360h45| TDK| CLF6045NIT-6R8N-D
COUT1 to 4(Note 1)| 10μF x 3 (Mounted on Board)or| 1210| 3225| Murata| GCM32ER71E106K
22μF x 2or| 1210| 3225| Murata| GCM32ER71A226K
22μF x 3| 0805| 2012| Murata| GCM21BD70J226M
RFB0| 0Ω| 0402| 1005| ROHM| MCR01 Series
RFB1| 68kΩ| 0402| 1005| ROHM| MCR01 Series
RFB2| 13kΩ| 0402| 1005| ROHM| MCR01 Series
CFB1 (Note 4)| Open| –| –| –| –
CFB2 (Note 4)| Open| –| –| –| –
RDIS| 0Ω| 0402| 1005| ROHM| MCR01 Series
RDISN| Open| –| –| –| –
REX (Note 2)| 0Ω| 0402| 1005| ROHM| MCR01 Series
REXN (Note 2)| Open| –| –| –| –

(Note 1)

* VOUT is the output voltage [V]
(Note 1-1) When selecting the output capacitor, ensure that the capacitance, COUT_WORST, of the above equation is maintained at the characteristics of DC Bias, AC Voltage, temperature, and tolerance.
(Note 1-2) If the capacitance falls below this value, oscillation may happen. When using electrolytic capacitor and conductive polymer hybrid aluminum electrolytic capacitor, please place it in addition to the ceramic capacitors with the capacity described above. The changes in the frequency characteristic are greatly affected by the type and the condition (temperature, etc.) of parts that are used, the wire routing and the layout of the PCB. Please confirm stability and responsiveness in actual application.
(Note 2) VCC_EX is power supply input for internal circuit. VREG voltage is supplied from VCC_EX when voltage between 3.2V (VTEXH, Max) and 5.65 V (VEXOVPL, Min) is connected to this pin. Connecting this pin to VOUT improves efficiency. In case of not use this function, connect this pin to GND.

(Note 3) RESET terminal should be pulled-up to VREG via RRST2 when the output setting is over 6.5 V because RESET pin’s absolute maximum rating is 7.0 V. If RESET is not pulled-up to VOUT, it can be pulled-up to VREG via RRST2 by  default.

(Note 4) Please use CFB1 and CFB2 PCB patterns to improve the frequency characteristics. Set these values by following the guide in page 31 of datasheet.

(Note 5) If the recommended parts on tables 3 to 7 are not available anymore due to end of production, different parts will be used on the test board because the end of production parts are deprecated.

Board Layout

Evaluation Board PCB information}

2oz(70μm)

The layout is shown below.

Figure 4. Top Layer Layout (Top View)

Figure 5. Middle1 Layer Layout (Top View)

Figure 6. Middle2 Layer Layout (Top View)

Figure 7. Bottom Layer Layout (Top View)

Revision History

Notice

1. The information contained in this document is intended to introduce ROHM Group (hereafter referred to as ROHM) products. When using ROHM products, please verify the latest specifications or datasheets before use.
2. ROHM products are designed and manufactured for use in general electronic equipment and applications (such as Audio Visual equipment, Office Automation equipment, telecommunication equipment, home appliances, amusement devices, etc.) or specified in the datasheets. Therefore, please contact the ROHM sales representative before using ROHM products in equipment or devices requiring extremely high reliability and whose failure or malfunction may cause danger or injury to human life or body or other serious damage (such as medical equipment, transportation, traffic, aircraft, spacecraft, nuclear power controllers, fuel control, automotive equipment including car accessories, etc. hereafter referred to as Specific Applications). Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any damages, expenses, or losses incurred by you or third parties arising from the use of ROHM Products for Specific Applications.
3. Electronic components, including semiconductors, can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate safety measures including but not limited to fail-safe design against physical injury, and damage to any property, which a failure or malfunction of products may cause.
4. The information contained in this document, including application circuit examples and their constants, is intended to explain the standard operation and usage of ROHM products, and is not intended to guarantee, either explicitly or implicitly, the operation of the product in the actual equipment it will be used. As a result, you are solely responsible for it, and you must exercise your own independent verification and judgment in the use of such information contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses, or losses incurred by you or third parties arising from the use of such information.
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