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© 2014 ROHM Co., Ltd. All rights reserved. www.rohm.com 9 December 2014 Rev.002

Switching Regulator Series Step-Down DC/DC Converter BD9C401EFJ Evaluation Board BD9C401EFJ-EVK-001

Description This evaluation board has been developed for ROHM’s synchronous buck DC/DC converter customers evaluating BD9C401EFJ. While accepting a power supply of 4.72-18V, an output of 3.3V can be produced. The IC has internal 65mΩ high-side P-channel MOSFET and 35mΩ low-side N-channel MOSFET and a synchronization frequency is of 500kHz. A Soft Start circuit prevents in-rush current during startup. An EN pin allows for simple ON/OFF control of the IC to reduce standby current consumption. Include OCP (Over Current Protection) and SCP (Short Circuit Protection).

Evaluation Board Operating Limits and Absolute Maximum Ratings (Ta=25)

Parameter Symbol Limit

Unit Conditions MIN TYP MAX

Supply Voltage VCC 4.5 - 18 V

Output Voltage / Current

VOUT - 3.3 - V

IOUT - - 4 A

(NOTE1) When the output voltage is 3.3V, it is 4.72V by limiting ratio of the maximum duty.

Evaluation Board

Figure 1. BD9C401EFJ-EVK-001 Evaluation Board

(NOTE1)

BD

© 2ww

Op 1. N

2. C

En

It abetwh

D

D9C401EF

2014 ROHM Coww.rohm.com

peration Pro

Necessary eq

(1) DC powe

(2) Maximum

(3) DC voltme

Connecting th

(1) DC powe

(2) The max.

(3) Check Ju

(4) Connect p

(5) Connect l

(6) Connect p

(7) Connect p

(8) DC powe

(9) IC is enab

(10) Check D

(11) The load

(12) Check a

nable-Pin

To minimizeEN pin(6pin)OFF-side ter

also can be swtween EN anden it is over 2

DC Pow

DC Voltmeter 1

FJ-EVK-00

o., Ltd. All rights

ocedures

uipments

r-supply of 4.7

m 4A load

eter

he equipments

r-supply prese

load should b

mper pin of S

positive-termin

load’s positive

positive-termin

positive-termin

r-supply outpu

ble (EN) by sh

DC voltmeter 2

d is enabled.

at DC voltmete

e current cons) of the IC. Sminal and norwithed betweed GND-termina.0V.

+

-

+

-

wer

V

01

reserved.

7V to 18V/4A

s

ets to 12V and

be set at 4A an

W1 is short, b

nal of power-s

e-terminal to V

nal of DC voltm

nal of DC voltm

ut is turned ON

horting Jumpe

2 displays 3.3V

er 1 whether th

sumption durinStandby-modermal-mode opeen standby-moal. Standby-m

d then the pow

nd over it will b

between interm

supply to VIN+

VOUT+termina

meter 1 to TP

meter 2 to TP3

N.

r-pin of SW1 b

V.

he voltage-dro

Figure 2

ng standby-moe is enabled eration by shoode and norm

mode is enable

2/8

wer output turn

be disabled.

mediate-termin

+terminal and

al and negative

1 and negativ

3 and negativ

between interm

op (loss) is not

2. Connection

ode and normby shorting

orting betweenmal-mode opered when the v

ns off.

nal and OFF-s

negative-term

e-terminal to G

e-terminal to T

e-terminal to T

mediate-termi

t caused by th

Diagram

mal operation, Jumper-pin o

n intermediateration by removoltage of EN

9

side terminal.

minal to GND-te

GND-terminal

TP2 for input-v

TP4 for output

nal and ON-si

he wire’s resist

Enable-mode of SW1 betwe-terminal and

oving Jumper-is under 0.8V

9 December

erminal with a

with a pair of

voltage measu

t-voltage mea

ide terminal.

tance.

can be switcheen intermedON-side term

-pin and contrV, and normal-

+

-

+

- V

r 2014 Rev.0

a pair of wires.

wires.

urement.

surement.

hed by controliate-terminal

minal. rolling the voltmode opera

DC Voltmete

Load

002

.

lling and

tage ation

r 2

3/8

BD9C401EFJ-EVK-001

9 December 2014 Rev.002© 2014 ROHM Co., Ltd. All rights reserved. www.rohm.com

2 VIN

6 EN

1 PGND

3 AGND

R3

C6SW1

ON

O FF

C2 C3 TP 1

V I N

GND

SW 8

TP5L1

C 4 C5

TP3

VOUT

GND

FB 4

R2

R 1

C 7

U1

BD9C401EFJ

COMP 5

TP 2

C1

TP4

J1 J2

TP6

SW 7

9 E-PAD

1 C1 Ceramic Capacitor 0.1µF 50V, B, ±20% GRM188B31H104MA92 MURATA 1608

1 C2 Ceramic Capacitor 10µF 35V, B, ±10% GRM32EB3YA106KA12 MURATA 3225

0 C3 Ceramic Capacitor - Not installed - MURATA 3225

2 C4, C5 Ceramic Capacitor 22µF 10V, B, ±10% GRM31CB31A226KE19 MURATA 3216

1 C6 Ceramic Capacitor 4700pF 25V, B, ±10% GRM188B11E472KA01 MURATA 1608

1 C7 Ceramic Capacitor 33pF 50V, C0G, ±5% GRM1885C1H330JA01 MURATA 1608

1 L1 Inductor 4.7µH ±20%, DCR=39.4mΩmax, 6.2A SPM6530T-4R7 TDK 7165

1 R1 Resistor 7.5kΩ 1/10W, 50V, 1% MCR03ERPF7501 ROHM 1608

1 R2 Resistor 2.4kΩ 1/10W, 50V, 1% MCR03ERPF2401 ROHM 1608

1 R3 Resistor 12kΩ 1/10W, 50V, 1% MCR03ERPF1202 ROHM 1608

1 SW1 Pin header - 2.54mm × 3 contacts PH-1x03SG USECONN -

1 U1 IC - Buck DC/DC Converter BD9C401EFJ ROHM HTSOP-J8

2 J1, J2 Terminal Block - 2 contacts, 15A, 14 to 22AWG TB111-2-2-U-1-1Alphaplus

Connectors & Cables

-

1 - Jumper - Jumper pin for SW1 MJ254-6BK USECONN -

ReferenceDesignator

CountManufacturerPart Number

ManufacturerConfiguration

(mm)Type Value Description

Cricuit Diagram

VIN = 4.72V～18V, VOUT = 3.3V

Figure 3. BD9C401EFJ-EVK-001 Circuit Diagram Bill of Materials

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BD9C401EFJ-EVK-001

9 December 2014 Rev.002© 2014 ROHM Co., Ltd. All rights reserved. www.rohm.com

Layout

Figure 4. Top Silk Screen (Top view)

Figure 5. Top Silk Screen and Layout (Top view)

5/8

BD9C401EFJ-EVK-001

9 December 2014 Rev.002© 2014 ROHM Co., Ltd. All rights reserved. www.rohm.com

Figure 6. Top Side Layout (Top view)

Figure 7. L2 Layout (Top view)

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BD9C401EFJ-EVK-001

9 December 2014 Rev.002© 2014 ROHM Co., Ltd. All rights reserved. www.rohm.com

Figure 8. L3 Layout (Top view)

Figure 9. Bottom Side Layout (Top view)

BD

© 2ww

Effi

i(%

)O

utpu

t Vol

tage

(V

)

D9C401EF

2014 ROHM Coww.rohm.com

0

10

20

30

40

50

60

70

80

90

100

0

Effi

cien

cy (

%)

3.25

3.26

3.27

3.28

3.29

3.30

3.31

3.32

3.33

3.34

3.35

0

FJ-EVK-00

o., Ltd. All rights

0.5 1

L

Figure 10. E

Figure

1

Lo

01

reserved.

1.5

oad Current

Efficiency vs L

e 12. Load Re

2

ad Current (A

2 2.5

(A)

VIN=12VVO=3.3V

oad Current

gulation

3

A)

VIN=1VO=3.

7/8

3

VV

VO (A100m

IO: 1

3

3

3

3

3

3

3

3

3

3

3

Out

put V

olta

ge (

V)

4

2V.3V

F

AC) mV/div

1A/div

3.20

3.22

3.24

3.26

3.28

3.30

3.32

3.34

3.36

3.38

3.40

4 6

9

Figure

igure 13. Load

IO: 0A

6 8

Inp

9 December

11. Line Regu

d Transient Ch

Time

VV

A→2A→0A

10 12

put Voltage (

r 2014 Rev.0

ulation

haracteristics

e scale 1ms/d

VIN = 12V VO = 3.3V

14 16

V)

VO=3.3VIO=0A

002

div

18

V

BD

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V2

D9C401EF

2014 ROHM Coww.rohm.com

VIN (AC) 20mV/div

VSW 5V/div

VSW

10V/div

EN 5V/div

VO 2V/div

FJ-EVK-00

o., Ltd. All rights

Figure 14. OuV

Figure 16. V

01

reserved.

utput Voltage VIN = 12V, VO

T

Start-up by ENVIN = 12V, VO

T

Ripple Wave= 3.3V

Time scale 1

IO = 0A

N = 3.3V, IO = 0

Time scale 1m

8/8

μs/div

VIN (A20m

V5

0A

ms/div

VSW

10V

EN5V

VO

2V

Fig

AC) V/div

VSW 5V/div

F

W

V/div

N V/div

O V/div

9

gure 15. OutpVIN

Figure 17. PowVIN

9 December

put Voltage Rip = 12V, VO = 3

Tim

Time s

wer-down by E= 12V, VO = 3

r 2014 Rev.0

pple Wave 3.3V

IO = 4A

e scale 1μs/d

scale 200ms/d

EN 3.3V, IO = 0A

002

div

div

R1102Awww.rohm.com© 2014 ROHM Co., Ltd. All rights reserved.

Notice

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N o t e s

The information contained herein is subject to change without notice.

Before you use our Products, please contact our sales representative and verify the latest specifica-tions :

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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.

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