Rohm BD9G101G Installation and operating instructions

1
ROHM Switching Regulator Solutions
Evaluation Board:
Step-down Switching Regulator
With Built-in Power MOSFET
BD9G101G (5V | 0.5A Output)
●Introduction
This application note will provide the steps necessary to operate and evaluate ROHM’s step-down switching regulator using the BD9G101G
evaluation boards. Board layout recommendations, operation procedures, application data and build of materials are provided.
●Description
This evaluation board has been developed for ROHM’s step-down switching regulator customers evaluating BD9G101G. While accepting a
wide power supply of 6-42V, a step down output of 1V-29V can be produced. The IC has an internal 800mohm Nch MOSFET (1A max) and
a fixed operating frequency range of 1.5MHz. A Soft Start circuit prevents in-rush current during startup along with UVLO (low voltage error
prevention circuit), OCP (over-current protection) and TSD (thermal shutdown detection) protection circuits. An EN pin allows for simple
ON/OFF control of the IC to reduce standby current consumption.
●Applications
Industrial distributed power applications
Automotive and battery powered equipment
●Evaluation Board Operating Limits and Absolute Maximum Ratings
Parameter
Symbol
Limit
Unit
Conditions
MIN
TYP
MAX
Supply Voltage
BD9G1010G
VCC
6
-
42
V
Output Voltage / Current
BD9G101G
VOUT
-
5
-
V
*Set by R1 and R2
BD9G101G
IOUT
-
0.5
-
A
●Evaluation Board
Below is the evaluation board with the BD9G101G. Component selection and board layout guidelines are provided in the
BD9G101G datasheet.
No.0000000015
BD9673EFJ Eval Board
BD9G101G Eval Board (Back)
GND
Vout
BD9G101G Eval Board (Front)
EN
VOUT
VCC
GND
ENABLE
H: Active
(ICOFF)
L: Inactive
(ICON)

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●Evaluation Board Schematic
Below is the evaluation board schematic for BD9G101G.
●Evaluation Board I/O
Below is the reference application circuit that shows the inputs (Vcc and EN) and the output (Vout @ 5V/0.5A)
●Evaluation Board Operation Procedures
Below is the procedure to operate the evaluation board
1. Connect GND to a GND pin on the evaluation board
2. Connect Vcc to the VCC_pin. This will provide Vcc to the Vcc pin of the IC
i. Note: EN pin is pulled HIGH as default. EN needs to be set to LOW for IC operation.
3. Output voltage can be measured from the VOUT_pin on the evaluation board. Output current can be measured with a
proper load at VOUT.
L1: 10uH
10uH

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●Reference Graphs Application Data for BD9G101G
Below graphs show efficiency, frequency response and load characteristics of the BD9G101G eval board.

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Note: Feed-forward capacitor Csp is not populated on the BD9G101G evaluation board. The capacitor is recommended
for designs requiring improved phase margin and transient response.
●Evaluation Board Layout Guidelines
Below are the guidelines that have been followed and recommended for BD9G101G designs.

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●Evaluation Board BOM
Below is a table with the build of materials. Part numbers and supplier references are provided.
Item
Qty
Ref
Description
Manufacturer
Part Number
Digikey P/N
1
1
CIN1
CAP CER 4.7UF 50V Y5V 1206
Murata
GRM31CF51H475ZA01L
490-1828-1-ND
2
1
CIN2
DIODE TVS 30V 400W UNI 5%
SMA
Littlefuse
SMAJ30A
SMAJ30ALFTR-ND
3
1
CO2
CAP CER 10UF 10V 10% X5R
1206
Murata
GRM31CR61A106KA01L
490-1820-2-ND
4
1
CBST
CAP CER 0.015UF 50V 10% X7R
0603
Murata
GRM188R71H153KA01D
490-1514-1-ND
5
1
D1
DIODE SCHOTTKY 60V 2A PMDU
ROHM
RB060M-60TR
RB060M-60CT-ND
6
1
SW1
SWITCH SLIDE SPDT 30V.2A PC
MNT
E-Switch
EG1218
EG1903-ND
7
1
R1
RES 68.0K OHM 1/8W 1% 0805
SMD
Yageo
RC0805FR-0768KL
311-68.0KCRCT-ND
8
1
R2
RES 12.0K OHM 1/8W 1% 0805
SMD
Yageo
RC0805FR-0712KL
311-12.0KCRCT-ND
9
1
LX
INDUCT 10uH SOD-106
TOKO
DEM4518C
1235AS-H-100M
-
10
1
U1
5V, 0.5A Step-down SW Reg w/
FET
ROHM
BD9G101G
-

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