BD9524MUV-E2 - ROHM Co., Ltd.

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www.rohm.com 2010.03 - Rev.C

Hi-performance Regulator IC Series for PCs

Main Power Supply IC

for Note PC (Linear Regulator Integrated)

BD9524MUV

●Description

BD9524MUV is a switching regulator controller with high output current which can achieve low output voltage (2.0V～5.5V)

from a wide input voltage range (7V~25V). High efficiency for the switching regulator can be realized by utilizing an external

N-MOSFET power transistor. A new technology called H3RegTM is a Rohm proprietary control method to realize ultra high

transient response against load change. SLLM (Simple Light Load Mode) technology is also integrated to improve efficiency

in light load mode, providing high efficiency over a wide load range. For protection and ease of use, the soft start function,

variable frequency function, short circuit protection function with timer latch, over voltage protection with timer latch, and

Power good function are all built in. This switching regulator is specially designed for Main Power Supply.

●Features

1) 2ch H3RegTM Switching Regulator Controller

2) Adjustable Simple Light Load Mode (SLLM), Quiet Light Load Mode (QLLM) and Forced continuous Mode

3) Thermal Shut Down (TSD), Under Voltage Lock Out (UVLO), Over Current Protection (OCP),

Over Voltage Protection (OVP), Short circuit protection with timer-latch (SCP)

4) Soft start function to minimize rush current during startup

5) Switching Frequency Variable (f=200KHz～500KHz)

6) Power good circuit

7) 2ch Linear regulator

8) VQFN032V5050 package

●Applications

Laptop PC, Desktop PC, LCD-TV, Digital Components

●Maximum Absolute Ratings (Ta=25℃)

*1 Do not however exceed Pd.

*2 Instantaneous surge voltage, back electromotive force and voltage under less than 10% duty cycle.

*3 Reduced by 3.0mW for each increase in Ta of 1℃ over 25℃ (when don’t mounted on a heat radiation board )

*4 Reduced by 7.0mW for increase in Ta of 1℃ over 25℃. (when mounted on a board 70.0mm×70mm×1.6mm Glass-epoxy PCB

which has 1 layer. (Copper foil area : 0mm2))

*5 Reduced by 16.5mW for increase in Ta of 1℃ over 25℃. (when mounted on a board 70.0mm×70mm×1.6mm Glass-epoxy PCB

which has 4 layers. (1st and 4th copper foil area : 20.2mm2, 2nd and 3rd copper foil area : 5505mm2))

*6 Reduced by 36.5mW for increase in Ta of 1℃ over 25℃. (when mounted on a board 70.0mm×70mm×1.6mm Glass-epoxy PCB

which has 4 layers. (All copper foil area : 5505mm2))

Parameter Symbol Limits Unit

Terminal voltage

VIN, CTL 30 *1*2 V

EXTVCC, PGOOD1, PGOOD2FB1, FB2, Is+1, Is+2, MCTL 7*1*2 V

FS1, FS2, REF1, REF2, SS1, SS2, LG1, LG2 REG1+0.3*1*2 V

BOOT1, BOOT2 35*1*2 V

BOOT1-SW1, BOOT2-SW2, HG1-SW1, HG2-SW2 7*1*2 V

HG1 BOOT1+0.3*1*2 V

HG2 BOOT2+0.3 *1*2 V

EN1, EN2 6 *1*2 V

DGND, PGND1, PGND2 AGND±0.3 *1*2 V

Power dissipation 1 Pd1 0.38 *3 W

Power dissipation 2 Pd2 0.88 *4 W

Power dissipation 3 Pd3 2.06 *5 W

Power dissipation 4 Pd4 4.56 *6 W

Operating temperature range Topr -10 ~ +100 ℃

Storage temperature range Tstg -55 ~ +150 ℃

Junction Temperature Tjmax +150 ℃

No.10030ECT06

BD9524MUV

Technical Note

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www.rohm.com 2010.03 - Rev.C

●Operating Conditions (Ta=25℃)

Parameter Symbol MIN. MAX. Unit

Terminal voltage

VIN 7 25 V

EXTVCC 4.5 5.5 V

CTL -0.3 25 V

EN1, EN2 -0.3 5.5 V

BOOT1, BOOT2 4.5 30 V

BOOT1-SW1, BOOT2-SW2, HG1-SW1, HG2-SW2 -0.3 5.5 V

PGOOD1, PGOOD2 -0.3 5.5 V

FS1, FS2 0.09 1.25 V

REF1, REF2 1 2.75 V

Is+1, Is+ 2, FB1, FB2 1.9 5.6 V

MCTL -0.3 REG1+0.3 V

*This product should not be used in a radioactive environment.

●Electrical characteristics

(unless otherwise noted, Ta=25℃ VIN=12V, CTL=5V, EN1=EN2=5V, REF1=2.5V, REF2=1.65V, FS1=FS2=0.582V)

Parameter Symbol

Standard Value Unit Conditions

MIN. TYP. MAX.

VIN standby current ISTB 70 150 250 μA CTL=5V, EN1=EN2=0V

VIN bias current IIN 0 45 130 μA EXTVCC=5V

Shut down mode current ISHD -10 0 10 μA CTL=0V

CTL Low voltage VCTLL -0.3 - 0.8 V

CTL High voltage VCTLH 2.3 - 25 V

CTL bias current ICTL - 1 3 μA VCTL=5V

EN Low voltage VENL -0.3 - 0.8 V

EN High voltage VENH 2.3 - 5.5 V

EN bias current IEN - 1 3 μA VEN=3V

[5V linear regulator]

REG1 output voltage VREG1 4.90 5.00 5.10 V IREG1=1mA

Maximum current IREG1 200 - - mA IREG2=0mA

Line Regulation REG1I - 90 180 mV VIN=7.5 to 25V

Load Regulation REG1L - 30 50 mV IREG1=0 to 30mA

[3.3V linear regulator]

REG2 output voltage VREG2 3.27 3.30 3.33 V IREG2=1mA

Maximum current IREG2 100 - - mA

Line regulation REG2I - - 20 mV VIN=7.5 to 25V

Load regulation REG2L - - 30 mV IREG2=0 to 100mA

[5V switch block]

EXTVCC input threshold voltage VCC_UVLO 4.2 4.4 4.6 V EXTVCC: Sweep up

EXTVCC input delay time TVCC 2 4 8 ms

Switch Resistance RVCC 1.0 2.0 Ω

[Under voltage lock out block for DC/DC]

REG1 threshold voltage REG1_UVLO 4.0 4.2 4.4 V REG1: Sweep up

REG2 threshold voltage REG2_UVLO 2.45 2.65 2.85 V REG2: Sweep up

Hysteresis voltage dV_UVLO 50 100 200 mV REG1, REG2: Sweep down

[Error amplifier block]

Feedback voltage 1 VFB1 REF1×2

-25m REF1×2REF1×2

+25m V

FB1 bias current IFB1 20 45 90 μA FB1=5V

Output discharge resistance 1 RDISOUT1 0.5 1 3 kΩ

Feedback voltage 2 VFB2 REF2×2

-25m REF2×2REF2×2

+25m V

FB2 bias current IFB2 10 30 60 μA FB2=3.3V

Output discharge resistance 2 RDISOUT2 0.5 1 3 kΩ

REF1, REF2 bias current IREF1, IREF2 -10 - 10 μA

BD9524MUV

Technical Note

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●Electrical characteristics - Continued

(unless otherwise noted, Ta=25℃ VIN=12V, CTL=5V, EN1=EN2=5V, REF1=2.5V, REF2=1.65V, FS1=FS2=0.582V)

Parameter Symbol

Standard Value Unit Conditions

MIN. TYP. MAX.

[H3RegTM block]

On Time 1 TON1 0.810 0.960 1.110 μs REF=2.5V

On Time 2 TON2 0.520 0.670 0.820 μs REF=1.65V

Maximum On Time TONMAX 3.5 7 14 μs

Minimum Off Time TOFFMIN - 0.2 0.4 μs

FS1, FS2 bias current IFS -10 0 10 μA

[FET driver block]

HG higher side ON resistor HGHON - 3.0 6.0 Ω

HG lower side ON resistor HGLON - 2.0 4.0 Ω

LG higher side ON resistor LGHON - 2.0 4.0 Ω

LG lower side ON resistor LGLON - 0.5 1.0 Ω

[Over Voltage Protection block]

Latch Type OVP Threshold voltage VLOVP REF×2

×1.15

REF×2

×1.175

REF×2

×1.20 V

Latch Type OVP delay time TLOVP 50 150 300 μs

[Short circuit protection block]

SCP Threshold voltage VSCP REF×2×

0.66

REF×2

×0.7

REF×2

×0.74 V

Delay time TSCP 0.5 1 2 ms

[Current limit protection block]

Maximum offset voltage dVSMAX 50 65 80 mV

Is+1 bias current IISP1 - 2.5 10 μA

Is+2 bias current IISP2 - 2.5 10 μA

[Power good block]

Power good low threshold VPGTHL REF×2

×0.87

REF×2

×0.90

REF×2

×0.93 V

Power good high threshold VPGTHH REF×2

×1.07

REF×2

×1.10

REF×2

×1.13 V

Power good low voltage VPGL - 0.1 0.2 V IPGOOD=1mA

Power good leakage current ILEAKPG -2 0 2 μA VPGOOD=5V

[Soft Start block]

Charge current ISS 1.8 2.5 3.2 μA

Standby voltage VSS_STB - - 50 mV

[SLLM mode control block]

MCTL terminal voltage 1 VCONT -0.3 - 0.3 V Continuous mode

MCTL terminal voltage 2 VQLLM 1.5 - 3.0 V QL2M mode

(Maximum LG off time : 50μs)

MCTL terminal voltage 3 VSLLM 4.5 - REG1+0.3 V SL2M mode

(Maximum LG off time : ∞)

MCTL float level VMCTL 1.5 - 3.0 V

●Output condition table

Input Output

CTL EN1 EN2 REG1(5V) REG2(3.3V) DC/DC1 DC/DC2

Low Low Low OFF OFF OFF OFF

Low Low High OFF OFF OFF OFF

Low High Low OFF OFF OFF OFF

Low High High OFF OFF OFF OFF

High Low Low ON ON OFF OFF

High Low High ON ON OFF ON

High High Low ON ON ON OFF

High High High ON ON ON ON

BD9524MUV

Technical Note

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www.rohm.com 2010.03 - Rev.C

●Block Diagram, Application circuit

*Apply the supply voltage EXTVCC pin after REG1 pin is operated.

REG1

Overlap

Protection

Circuit

Overlap

Protection

Circuit

SL2MTM

Block

SL2MTM

Block

H3RegTM

Controller

Block

H3RegTM

Controller

Block

5V

Reg

3.3V

Reg

Reference

Block

Thermal

Protection

CL2

SCP2

CL1

SCP1

REG1 REG1

FS2 FS1

REG1

VIN

Vo2

A

djustable

REG1

VIN

Vo1

A

djustable

VIN

REG2

Timer

SCP2

SCP1

Short Circuit Protect

Over Voltage

Protect

Over Voltage

Protect

EN2 EN1

TSD

UVLO

CL2

CL1

FB2

FB1

VIN

BOOT2

HG2

SW2

LG2

PGND2

BOOT1

HG1

SW1

LG1

PGND1

AGND

DGND

FS1

FB1

REF1

PGOOD1

Is+1

EN1

EN2

Is+2

PGOOD2

REF2

FB2

1

2

3

4

5

VIN

CTL

EXTVCC

REG1

REG2

VIN

7～

25V

REG1

5V

3.3V

30 18 27 29 28

21

16

20

17

15

31 32 22 23 24 26 25

13

7

14

8

10

9

REF2

FB2

REF1

FB1

REG2

MCTL2 MCTL1

SS2

SS1

Power Good Block

FS2

11

12

MCTL MCTL2

MCTL1

SL2M Mode Control

6

SS2 SS2

Soft Start Block

19

SS1 SS1

Soft Start Block

VIN

Current Limit

Protect

Current Limit

Protect

BD9524MUV

Technical Note

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www.rohm.com 2010.03 - Rev.C

●Pin Configuration

●Pin Function Table

PIN No. PIN name PIN Function

1 SW2 Highside FET source pin 2

2 HG2 Highside FET gate drive pin 2

3 BOOT2 HG Driver power supply pin 2

4 EN2 Vo2 ON/OFF pin (High=ON, Low=OFF)

5 PGOOD2 Vo2 Power Good Open Drain Output pin

6 SS2 Vo2 soft start pin

7 DGND Ground

8 REF2 Vo2 output voltage setting pin

9 Is+2 Current sense pin +2

10 FB2 Vo2 output voltage sense pin, current sense pin -2

11 FS2 Input pin for setting Vo2 frequency

12 MCTL Mode shift pin (Low=continuous, Middle=QLLM, High=SLLM)

13 AGND Input pin Ground

14 FS1 Input pin for setting Vo1 frequency

15 FB1 Vo2 output voltage sense pin, current sense pin -1

16 Is+1 Current sense pin +1

17 REF1 Vo1 output voltage setting pin

18 CTL Linear regulator ON/OFF pin (High=ON, Low=OFF)

19 SS1 Vo1 soft start pin

20 PGOOD1 Vo1 Power Good Open Drain Output pin

21 EN1 Vo1 ON/OFF pin (High=ON, Low=OFF)

22 BOOT1 HG Driver power supply pin 1

23 HG1 Highside FET gate drive pin 1

24 SW1 Highside FET source pin 1

25 PGND1 Lowside FET source pin 1

26 LG1 Lowside FET gate drive pin 1

27 EXTVCC Outside power supply input pin

28 REG2 3.3V linear regulator output pin

29 REG1 5V linear regulator output pin

30 VIN Power supply input pin

31 LG2 Lowside FET gate drive pin 2

32 PGND2 Lowside FET source pin 2

Reverse FIN Exposed Pad, Connect to GND

31 2 4 5678

9

10

11

12

13

14

15

16

24 23 22 21 20 19 18 17

32

31

30

29

28

27

26

25

PGND1

LG1

SW2

HG2

BOOT2

EN2

PGOOD2

SS2

DGND

REF2

SW1

HG1

BOOT1

EN1

PGOOD1

SS1

CTL

REF1

Is+1

FB1

FS1

A

GND

MCTL

FS2

FB2

Is+2

EXTVCC

REG2

REG1

VIN

LG2

PGND2

FIN

BD9524MUV

Technical Note

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●Reference data

Fig.1 wake up (Vo=5.0V) Fig.2 wake up (Vo=3.3V)

Fig.4 CONT Mode (Io=0A) Fig.5 CONT Mode (Io=0.4A) Fig.6 CONT Mode (Io=1.4A)

Fig.7 QLLM (Io=0A) Fig.8 QLLM (Io=0.4A) Fig.9 QLLM (Io=1.4A)

Fig.10 SLLM (Io=0A) Fig.11 SLLM (Io=0.4A) Fig.12 SLLM (Io=1.4A)

Fig.3 wake up (REG1, REG2)

EN

5V/div

PGOOD

5V/div

SS

1V/div

Vo

2V/div

EN

5V/div

PGOOD

5V/div

SS

1V/div

Vo

2V/div

Vo

20mV/di

v

IL

2A/div

SW

5V/div

LG

5V/div

Vo

20mV/di

v

IL

2A/di

v

SW

5V/di

v

LG

5V/di

v

Vo

20mV/di

v

IL

2A/div

SW

5V/div

LG

5V/div

Vo

20mV/di

v

IL

2A/div

SW

5V/div

LG

5V/div

Vo

20mV/di

v

IL

2A/di

v

SW

5V/di

v

LG

5V/di

v

Vo

20mV/di

v

IL

2A/di

v

SW

5V/di

v

LG

5V/di

v

Vo

20mV/di

v

IL

2A/div

SW

5V/div

LG

5V/div

Vo

20mV/di

v

IL

2A/di

v

SW

5V/di

v

LG

5V/di

v

Vo

20mV/di

v

IL

2A/div

SW

5V/div

LG

5V/div

CTL

10V/div

REG1

2V/div

REG2

2V/div

BD9524MUV

Technical Note

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www.rohm.com 2010.03 - Rev.C

●Reference data

0.0

0.5

1.0

1.5

0.00 0.40 0.80 1.20 1.60

FS[V]

ON TIME[usec]

Fig.13 FS-ON TIME

Vo=5.0V

Vo=3.3V

0.1

1

10

100

7 101316192225

VIN [V]

IVIN [mA]

Fig.17 VIN-IVIN (Io=0A, Vo1=5.0V)

CONT Mode

SLLM

QLLM

0

200

400

600

800

1000

1200

0.00 0.40 0.80 1.20 1.60

FS[V]

Frequency[kHz]

Fig.14 FS-frequency

QLLM, SLLM (3.3V)

CONT Mode (3.3V)

CONT Mode (5.0V)

VIN=12V, Vo=5.0V

0

10

20

30

40

50

60

70

80

90

100

1 10 100 1000 10000

Io [mA]

efficiency [%]

Fig.16 Io-efficiency (VIN=12V, Vo1=5.0V)

QLLM

SLLM

CONT Mode

0

50

100

150

200

250

300

350

400

450

500

0.001 0.01 0.1 1 10

Io [A]

frequency [KHz]

CONT Mode

(

VIN=7

)

CONT Mode (VIN=12)

CONT Mode (VIN=19)

(VIN=7, 12, 19V)

QLLM

SLLM

QLLM

,

SLLM

(

VIN=7

)

QLLM,SLLM (VIN=12)

Fig.15 Io-frequency (Vo1=5.0V)

QLLM,SLLM (VIN=19)

BD9524MUV

Technical Note

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●Pin Descriptions

・VIN

This is the main power supply pin. The input supply voltage range is 7V to 25V. The duty cycle of BD9524MUV is determined by

input voltage and control output voltage. Therefore, when VIN voltage fluctuated, the output voltage also becomes unstable.

Since VIN line is also the input voltage of switching regulator, stability depends on the impedance of the voltage supply. It is

recommended to establish bypass capacitor and CR filter suitable for the actual application.

・CTL

When CTL pin voltage is at least 2.3V the status of the linear regulator output becomes active (REG1=5V, REG2=3.3V).

Conversely, the status switches off when CTL pin voltage goes lower than 0.8V. The switching regulator doesn’t become active

when the status of CTL pin is low, if the status of EN pin is high.

・EN

When EN pin voltage is at least 2.3V, the status of the switching regulator becomes active. Conversely, the status switches off

when EN pin voltage goes lower than 0.8V.

・REG1

This is the output pin for 5V linear regulator and also active in power supply for driver and control circuit of the inside. The

standby function for REG1 is determined by CTL pin. The voltage is 5V, with 100mA current ability. It is recommended that a

10uF capacitor (X5R or X7R) be established between REG1 and GND.

・REG2

This is the output pin for 3.3V linear regulator. The standby function for REG2 is determined by CTL. The voltage is 3.3V, with

100mA current ability. It is recommended that a 10uF capacitor (X5R or X7R) be established between REG2 and GND. It is

available to set REF and SS by the resistance division value from REG2 in case REF are not set from an external power supply.

・EXTVCC

This is the external input pin to REG1. When EXTVCC is beyond 4.4V, it supplies REG1 as EXTVCC is the power supply.

・REF

This is the setting pin for output voltage of switching regulator. It is so convenient to be synchronized to outside power supply.

This IC controls the voltage in the status of 2×REF≒FB.

・FB

This is the feedback pin from the output of switching regulator. This IC controls the voltage in the status of 2×REF≒FB.

・SS

This is the setting pin for soft start. The rising time is determined by the capacitor connected between SS and GND, and the fixed

current inside IC after it is the status of low in standby mode. It controls the output voltage till SS voltage catch up the REF pin to

become the double of the SS terminal voltage.

・FS

This is the input pin for setting the frequency. It is available to set it in frequency range is 200KHz to 500kHz.

・Is+

This is the sense pin for output current. In case it is connected to side of the coil resistance for sense current and the voltage is

set 65mV(typ) or more higher than FB pin voltage, the switching operation turns OFF.

・PGOOD

This is the open drain pin for deciding the output of switching regulator.

・MCTL

This is the switching shift pin for SLLM (Simple Light Load Mode). The efficiency in SLLM mode improves in setting MCTL pin to

1.5V or more. In case MCTL terminal voltage range is from 1.5 to 3.0V, LG maximum OFF time is 40usec, from 4.5V to

REG1+0.3V, LG maximum OFF time is to infinity. It is in continuous mode that MCTL pin voltage is set 0.3V or less.

・AGND,DGND

This is the ground pin.

・BOOT

This is the power supply pin for high side FET driver. The maximum voltage range to GND pin is to 35V, to SW pin is to 7V. In

switching operations, the voltage swings from (VIN+REG1) to REG1 by BOOT pin operation.

・HG

This is the highside FET gate drive pin. It is operated in switching between BOOT to SW. In case the output MOS is 3ohm /the

status of Hi, 2ohm/the status of Low, it is operated hi-side FET gate in high speed.

・SW

This is the ground pin for high side FET drive. The maximum voltage range to GND pin is to 30V. Switching operation swings

from the status of BOOT to the status of GND.

・LG

This is the lowside FET gate drive pin. It is operated in switching between REG1 to PGND. In case the output MOS is 2ohm /the

status of Hi, 0.5ohm/the status of Low, it is operated low-side FET gate in high speed.

・PGND

This is the ground pin for low side FET drive.

BD9524MUV

Technical Note

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www.rohm.com 2010.03 - Rev.C

● Explanation of Operation

The BD9524MUV is a 2ch synchronous buck regulator controller incorporating ROHM’s proprietary H3RegTM CONTROLLA

control system. When VOUT drops due to a rapid load change, the system quickly restores VOUT by extending the TON

time interval. Thus, it serves to improve the regulator’s transient response. Activating the Light Load Mode will also exercise

Simple Light Load Mode (SLLM) control when the load is light, to further increase efficiency.

H3RegTM control

(Normal operation)

(VOUT drops due to a rapid load change)

Light Load Control

(SLLM)

(QLLM)

*Attention: H3RegTM CONTROLLA monitors the supplying current

from capacitor to load, using the ESR of output capacitor,

and realize the rapid response. Bypass capacitor used at

each load (Ex. Ceramic capacitor) exercise the effect

with connecting to each load side. Do not put a ceramic

capacitor on COUT side of power supply.

HG output is determined by the formula above.

When VOUT falls to a reference voltage (2×REF), the drop

is detected, activating the H3RegTM CONTROLLA system.

When VOUT drops due to a rapid load change, and the

voltage remains below reference voltage after the

programmed tON time interval has elapsed, the system

quickly restores VOUT by extending the tON time, improving

the transient response.

tON=2×REF

VIN × 1

f [sec]・・・(1)

In SLLM (MCTL=”High voltage”), when the status of LG is

OFF and the coil current is within 0A (it flows to SW from

VOUT.), SLLM function is operated to prevent output next

HG. The status of HG is ON, when VOUT falls belo

w

reference voltage again.

In QLLM (MCTL=”Hiz or Middle voltage”), when the status

of LG is OFF and the coil current is within 0A (it flows to

SW from VOUT.), QLLM function is operated to prevent

output next HG.

Then, VOUT falls below the output programmed voltage

within the programmed time (typ=40μs), the status of HG

is ON. In case VOUT doesn’t fall in the programmed time,

the status of LG is ON forcedly and VOUT falls. As a result,

he status of next HG is ON.

VOUT

2×REF

HG

LG

VOUT

HG

Io

LG

tON+α

VOUT

2×REF

HG

LG

0

A

VOUT

2×REF

HG

LG

0

A

Load

COUT

BD9524MUV

Technical Note

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www.rohm.com 2010.03 - Rev.C

● Timing Chart

• Soft Start Function

Soft start is exercised with the EN pin set high. Current

control takes effect at startup, enabling a moderate output

voltage “ramping start.” Soft start timing and incoming

current are calculated with formulas (2) and (3) below.

Soft start time

(Css: Soft start capacitor; Co: Output capacitor)

・Timer Latch Type Short Circuit Protection

Short protection kicks in when output falls to or below

REF × 1.4 (setting voltage × 0.7).

When the programmed time period elapses, output is

latched OFF to prevent destruction of the IC. Output

voltage can be restored either by reconnecting the EN pin

or disabling UVLO.

・Over Voltage Protection

・Over current protection circuit

EN

SS

VOU

T

IIN

TSS

Tss= REF×Css

2μA(typ)

[sec]

Incoming current

IIN= Co×VOUT

Tss

[A]

・・・(2)

・・・(3)

VOU

T

SCP

EN / UVLO

REF

×

1.4

150μs(typ)

or more

150μs(typ)

or less

150μs(typ)

Latch

VOUT

REF×2.35

OVP

EN / UVLO

When output rise to or above REF×2.35

(output setting voltage ×1.175), output over voltage

protection is exercised, and low side FET goes up

maximum for reducing output.（LG=High, HG=Low）. When

output falls within the programmed time (typ=150μs), it

returns to the standard mode. When the programmed time

period elapses, output is latched OFF to prevent

destruction of the IC. Output voltage can be restored eithe

r

by reconnecting the EN pin or disabling UVLO.

During the normal operation, when VOUT becomes less

than reference voltage, HG becomes High during the

time tON . However, when inductor current exceeds

ILIMIT threshold, HG becomes OFF.

A

fter 2.5μsec(typ), HG becomes ON again if the output

voltage is lower than the specific voltage level and IL is

lower than ILIMIT level.

2.5usec

tON tON

HG

LG

IL

ILIMIT

tON

2×REF

increase Io

Vo

BD9524MUV

Technical Note

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www.rohm.com 2010.03 - Rev.C

● External Component Selection

1. Inductor (L) selection

※Passing a current larger than the inductor’s rated current will cause magnetic saturation in the inductor and decrease

system efficiency. In selecting the inductor, be sure to allow enough margin to assure that peak current does not exceed

the inductor rated current value.

※To minimize possible inductor damage and maximize efficiency, choose a inductor with a low (DCR, ACR) resistance.

2.Output Capacitor (CO) Selection

Please give due consideration to the conditions in formula (8) below for output capacity, bear in mind that output rise time

must be established within the soft start time frame.

Note: Improper capacitor may cause startup malfunctions.

3. Input Capacitor (Cin) Selection

A low ESR capacitor is recommended to reduce ESR loss and maximize efficiency.

The inductor value is a major influence on the output ripple

current. As formula (4) below indicates, the greater the inductor o

r

the switching frequency, the lower the ripple current.

ΔIL=

(VIN-VOUT)×VOUT

L×VIN×f [A]・・・

(

4

)

The proper output ripple current setting is about 30% of maximum

out

p

ut current.

ΔIL=0.3×IOUTmax. [A]・・・(5)

L=

(VIN-VOUT)×VOUT

ΔIL×VIN×f

[

H

]

・・・

(

6

)

(ΔIL: output ripple current; f: switch frequency)

When determining the proper output capacitor, be sure to factor in the equivalent

series resistance required to smooth out ripple volume and maintain a stable

output voltage range.

Output ripple voltage is determined as in formula (7) below.

ΔVOUT=ΔIL×ESR [V]・・・(7)

(ΔIL: Output ripple current; ESR: CO equivalent series resistance)

※ In selecting a capacitor, make sure the capacitor rating allows sufficient

margin relative to output voltage. Note that a lower ESR can minimize output

ripple voltage.

Tss: Soft start time

Limit: Over current detection 2A(Typ)

Input Capacitor

The input capacitor selected must have low enough ESR resistance to fully

support large ripple output, in order to prevent extreme over current. The

formula for ripple current IRMS is given in (9) below.

IRMS=IOUT×

VIN

(

VIN-VOUT

)

VIN

[

A

]

・・・

(

9

)

√

Where VIN=2×VOUT,IRMS=

IOUT

2

ΔIL

VIN

IL

L

Co

VOUT

Output ripple current

Output Capacitor

VIN

L Co

VOUT

Cin

VIN

L

Co

VOUT

ESR

Load

CEXT

Co+CEXT≦ TSS×(Limit-IOUT)

VOUT ・・・

(

8

)

BD9524MUV

Technical Note

12/20

www.rohm.com 2010.03 - Rev.C

4. MOSFET Selection

5. Setting Detection Resistance (Detect ILIMIT at the peak current)

(A) High accuracy current detective circuit (use the low resistance)

(B) Low loss current detective circuit (use the DCR value of inductor)

(C) Low loss current detective circuit (the DCR value of inductor : high)

The over current protection function detects the output ripple

current peak value. This parameter (setting value) is

determined as in formula (13) below.

65mV(typ)

R

ILMIT=

(R: Detection resistance)

VIN

L

Co

VOUT

synchronous switch

main switch

Pmain=PRON+PGATE+PTRAN

Psyn=PRON+PGATE

VOUT

VIN

×RON×IOUT2+Ciss×f×VDD+ VIN2×Crss×IOUT×f

IDRIVE

VIN-VOUT

VIN

×RON×IOUT2+Ciss×f×VDD

Loss on the main MOSFET

(Ron: On-resistance of FET; Ciss: FET gate capacitance;

f: Switching frequency Crss: FET inverse transfer function;

IDRIVE: Gate peak current)

Loss on the synchronous MOSFET

=・・・(10)

=・・・(11)

[A]・・・(12)

ILMIT=65mV(typ)×

When the over current protection is detected by DCR of inductor L,

this parameter (setting value) is determined as in formula (13)

below.

(Application circuit:P18)

r×C

L

(RL: the DCR value of inductor)

[A]・・・(13)

L

r×C

(RL=)

VIN

L

Co

VOUT

Current limit

IL

R

65mV

OCP

VIN

L

Co

VOUT

Current limit

IL

RL

r C

65mV

OCP

(RL: the DCR value of inductor)

65mV(typ)

k×RL

ILIMIT=[A]・・・(14)

VIN

L

Co

VOUT

IL

(1-k)RL

R1

C

Current limit

65mV

R2

kRL

( RL

L

k= R1+R2

R2

= kR1C ) ,

BD9524MUV

Technical Note

13/20

www.rohm.com 2010.03 - Rev.C

6. Setting standard voltage (REF)

REF= ×REG2 [V]・・・(15)

7. Setting output voltage

This IC is operated that output voltage is REF×2≒FB.

And it is operated that output voltage is feed back to FB pin.

REF

FB

R0

It is available to set the reference voltage (REF)

by the resistance division value from REG2 in

case REF is not set from an external powe

r

supply.

FB

R0

H3RegTM

CONTROLLA S

RQ

VIN

REG2(3.3V)

R1

R2

REF

It is available to set the reference voltage (REF)

with outside supply voltage ×2 [V] by using

outside power supply voltage.

H3RegTM

CONTROLLA S

RQ

VIN

REF

R1+R2

R2

H3RegTM

CONTROLLA S

RQ SLLM

Driver

Circuit

SLLM

VIN

Output

voltage

VIN

FB

R0

Outside

voltage

BD9524MUV

Technical Note

14/20

www.rohm.com 2010.03 - Rev.C

●I/O Equivalent Circuit

1, 24pin (SW2, SW1) 2, 23pin (HG2, HG1) 3, 22pin (BOOT2, BOOT1)

4, 21pin (EN2, EN1) 5, 20pin (PGOOD2, PGOOD1) 6, 19pin (SS2, SS1)

8, 17pin (REF2, REF1) 9, 16pin (Is+2, Is+1) 10, 15pin (FB2, FB1)

11, 14pin (FS2, FS1) 12pin (MCTL) 18pin (CTL)

BOOT BOOT

SW

REG1

HG

SW

REG1

HG

BOOT

BD9524MUV

Technical Note

15/20

www.rohm.com 2010.03 - Rev.C

●I/O Equivalent Circuit

26, 31pin (LG1, LG2) 27pin (EXTVCC) 28pin (REG2)

29pin (REG1) 30pin (VIN)

●Evaluation Board Circuit (Vo1=5V f1=300kHz Vo2=3.3V f2=400kHz)

REG1 REG1

REG1

VIN

REG1

VIN

CTL

EN1

EN2

REG1

REG2

EXTVCC

REF1

REF2

SS1

FS1

BOOT1

HG1

SW1

LG1

PGND1

Is+1

FB1

BOOT2

HG2

SW2

LG2

PGND2

Is+2

VIN

12V

C1

CTL

R2

EN1

R3

EN2

R4

CTL

EN1

EN2

VIN

REG1

5V

REG2

3.3

V

EXTVCC

C2

C3

C4

REG2

R6

REG2

R8

R7 C5

R9 C6

C8 C7

FS1

R17

C18 R25

Q3

Q4

D4 C17

REG1

VIN VIN

C15 C16

SW2

D2

R39

R40

Q1

Q2

C24

D3 C27

VIN VIN

C25 C26

SW1

D1

30

18

21

4

29

28

27

17

8

19

6

14

22

23

24

26

25

16

15

3

2

1

31

32

9

BD9524MUV

R1

R5

Vo1

R16

REG2 VIN

R58

REG2

VIN

C19

R35

R32

R34

R30

R47

R49

R50

R46

L2 R33

R29

R28

VO2

C12

C11 C30 C29 C10

R31 C36 C13

R15

R26

R27

R18

C37

R22

L1 R48

R44 R43

R45 C34 C23

R10

R41

R42

R11

C35

R19

R56

R55

R57

Q5

TPQ6

VO1

C22

C21 C32

C33 C20

FS2

11

MCTL

DGND

A

GND

FB2

PGOOD1

PGOOD2

C14

R24

REG1

REG1 PGOOD2

PGOOD1

12

7

13

C28

C31

R14

MCTL

10

20

5

R20

R36

R21

R37

R13 R12

FS2 C9

R63

R52

R54

Q6

SS2

TPQ5

BD9524MUV

Technical Note

16/20

www.rohm.com 2010.03 - Rev.C

DESIGNATION RATING PART No. COMPANY

R1 0Ω MCR03EZHJ000 ROHM

R58 1MΩ MCR03PZHZF1004 ROHM

R2 0Ω MCR03EZHJ000 ROHM

R63 - - -

R3 0Ω MCR03EZHJ000 ROHM

C1 10uF(25V) CM32X7R106M25A KYOCERA

R4 0Ω MCR03EZHJ000 ROHM

C2 10uF(6.3V) GRM21BB10J106KD MURATA

R5 0Ω MCR03EZHJ000 ROHM

C3 10uF(6.3V) GRM21BB10J106KD MURATA

R6 15kΩ MCR03PZHZF1502 ROHM

C4 10uF(6.3V) GRM21BB10J106KD MURATA

R7 47kΩ MCR03PZHZF4702 ROHM

C5 0.01uF(50V) GRM188B11H103KD MURATA

R8 30kΩ MCR03PZHZF3002 ROHM

C6 0.01uF(50V) GRM188B11H103KD MURATA

R9 30kΩ MCR03PZHZF3002 ROHM

C7 1000pF(50 V) GRM188B11H102KD MURATA

R10 * - - -

C8 1000pF(50V) GRM188B11H102KD MURATA

R11 * - - -

C9 - - -

R12 - - -

C10 - - -

R13 1MΩ MCR03PZHZF1004 ROHM

C11 220uF 6TPE220MI SANYO

R14 51kΩ MCR03PZHZF5102 ROHM

C12 - - -

R15 * - - -

C13 * - - -

R16 - - -

C14 0.47uF(10V) GRM188B11A474KD MURATA

R17 36kΩ MCR03PZHZF3602 ROHM

C15 10uF(25V) CM32XR7106M25A KYOCERA

R18 * - - -

C16 10uF(25V) CM32XR7106M25A KYOCERA

R19 * - - -

C17 10uF(6.3V) GRM21BB10J106KD MURATA

R20 100kΩ MCR03PZHZF1003 ROHM

C18 - - -

R21 0Ω MCR03EZHJ000 ROHM

C19 - - -

R22 * - - -

C20 - - -

R24 0Ω MCR03EZHJ000 ROHM

C21 220uF 6TPE220MI SANYO

R25 0Ω MCR03EZHJ000 ROHM

C22 - - -

R26 * - - -

C23 * - - -

R27 * - - -

C24 0.47uF(10V) GRM188B11A474KD MURATA

R28 0Ω MCR03EZHJ000 ROHM

C25 10uF(25V) CM32XR7106M25A KYOCERA

R29 0Ω MCR03EZHJ000 ROHM

C26 10uF(25V) CM32XR7106M25A KYOCERA

R30 0Ω MCR03EZHJ000 ROHM

C27 10uF(6.3V) GRM21BB10J106KD MURATA

R31 * - - -

C28 - - -

R32 0Ω MCR03EZHJ000 ROHM

C29 - - -

R33 5mΩ PMR100HZPFU5L00 ROHM

C30 - - -

R34 0Ω MCR03EZHJ000 ROHM

C31 - - -

R35 0Ω MCR03EZHJ000 ROHM

C32 - - -

R36 100kΩ MCR03PZHZF1003 ROHM

C33 - - -

R37 0Ω MCR03EZHJ000 ROHM

C34 * - - -

R39 0Ω MCR03EZHJ000 ROHM

C35 * - - -

R40 0Ω MCR03EZHJ000 ROHM

C36 * - - -

R41 * - - -

C37 * - - -

R42 * - - -

D1 Diode RSX501L-20 ROHM

R43 0Ω MCR03EZHJ000 ROHM

D2 Diode RSX501L-20 ROHM

R44 0Ω MCR03EZHJ000 ROHM

D3 Diode RB520S-30 ROHM

R45 * - - -

D4 Diode RB520S-30 ROHM

R46 0Ω MCR03EZHJ000 ROHM

L1 2.5uH

CDEP105NP-2R5MC-

32 Sumida

R47 0Ω MCR03EZHJ000 ROHM

L2 2.5uH

CDEP105NP-2R5MC-

32 Sumida

R48 5mΩ PMR100HZPFU5L00 ROHM

Q1 FET uPA2702 NEC

R49 0Ω MCR03EZHJ000 ROHM

Q2 FET uPA2702 NEC

R50 0Ω MCR03EZHJ000 ROHM

Q3 FET uPA2702 NEC

R52 - - -

Q4 FET uPA2702 NEC

R54 - - -

Q5 - - -

R55 - - -

Q6 - - -

R56 - - -

U1 - BD9524MUV ROHM

R57 - - -

* Patterns for over current detection used DCR.

BD9524MUV

Technical Note

17/20

www.rohm.com 2010.03 - Rev.C

●Handling method of unused pin during using only 1ch DC/DC.

If using only 1ch DC/DC and 2ch pin is set to be off at all times, please manage the unused pin as diagram below.

PIN No, PIN Name Management

1 SW2 GND

2 HG2 OPEN

3 BOOT2 GND

4 EN2 GND

5 PGOOD2 GND

6 SS2 GND

8 REF2 GND

9 Is+2 GND

10 FB2 GND

11 FS2 GND

31 LG2 OPEN

REG1

VIN

CTL

EN1

EN2

REG1

REG2

EXTVCC

REF1

REF2

SS1

FS1

BOOT1

HG1

SW1

LG1

PGND1

Is+1

FB1

BOOT2

HG2

SW2

LG2

PGND2

Is+2

VIN

12V

C1

CTL

R2

EN1

R3

CTL

EN1

VIN

REG1

5V

REG2

3.3

V

EXTVCC

C2

C3

C4

REG2

R6

R7 C5

C7

FS1

R17

C18

R39

R40

Q1

Q2

C24

D3 C27

VIN VIN

C25 C26

SW1

D1

30

18

21

4

29

28

27

17

8

19

6

14

22

23

24

26

25

16

15

3

2

1

31

32

9

BD9524MUV

R1

R5

Vo1

R16

REG2 VIN

R58

C19

R47

R49

R50

R46

L1 R48

R44

R43

R45 C34 C23

R10

R41

R42

R11

C35

R19

R56

R55

R57

Q5

TPQ6

VO1

C22

C21 C32

C33 C20

FS2

11

MCTL

DGND

A

GND

FB2

PGOOD1

PGOOD2

REG1 PGOOD1

12

7

13

C28

MCTL

10

20

5

R20

R21

SS2

VO1

R51 R60

BD9524MUV

Technical Note

18/20

www.rohm.com 2010.03 - Rev.C

●Notes for use

1. This integrated circuit is a monolithic IC, which (as shown in the figure below), has P isolation in the P substrate and

between the various pins. A P-N junction is formed from this P layer and N layer of each pin, with the type of junction

depending on the relation between each potential, as follows:

 When GND> element A> element B, the P-N junction is a diode.

 When element B>GND element A, the P-N junction operates as a parasitic transistor.

Parasitic diodes inevitably occur in the structure of the IC. The operation of parasitic diodes can result in mutual

interference among circuits, as well as operating malfunctions and physical damage. Therefore, be careful to avoid

methods by which parasitic diodes operate, such as applying a voltage lower than the GND (P substrate) voltage to an

input pin.

2. In some modes of operation, power supply voltage and pin voltage are reversed, giving rise to possible internal circuit

damage. For example, when the external capacitor is charged, the electric charge can cause a VCC short circuit to the

GND. In order to avoid these problems, inserting a VCC series countercurrent prevention diode or bypass diode between

the various pins and the VCC is recommended.

3. Absolute maximum rating

Although the quality of this IC is rigorously controlled, the IC may be destroyed when applied voltage or operating

temperature exceeds its absolute maximum rating. Because short mode or open mode cannot be specified when the IC is

destroyed, it is important to take physical safety measures such as fusing if a special mode in excess of absolute rating

limits is to be implemented.

4.GND potential

Make sure the potential for the GND pin is always kept lower than the potentials of all other pins, regardless of the

operating mode.

5. Thermal design

In order to build sufficient margin into the thermal design, give proper consideration to the allowable loss (Power

Dissipation) in actual operation.

6. Short-circuits between pins and incorrect mounting position

When mounting the IC onto the circuit board, be extremely careful about the orientation and position of the IC. The IC may

be destroyed if it is incorrectly positioned for mounting. Do not short-circuit between any output pin and supply pin or

ground, or between the output pins themselves. Accidental attachment of small objects on these pins will cause shorts and

may damage the IC.

VCC

Countercurrent

Bypass diode

Resistor Transistor (NPN)

N

N N P+ P

+

P

P substrate

GND

Parasitic element

Pin A

N

N P+ P+

P

P substrate

GND

Parasitic element

Pin B C B

E

N

GND

Pin A

P

aras

iti

c

element

Pin B

Other adjacent elements

E

B C

GND

P

aras

iti

c

element

BD9524MUV

Technical Note

19/20

www.rohm.com 2010.03 - Rev.C

7. Operation in strong electromagnetic fields

Use in strong electromagnetic fields may cause malfunctions. Use extreme caution with electromagnetic fields.

8. Thermal shutdown circuit

This IC is provided with a built-in thermal shutdown (TSD) circuit, which is activated when the operating temperature

reaches 175℃ (standard value), and has a hysteresis range of 15℃ (standard). When the IC chip temperature rises to

the threshold, all the inputs automatically turn OFF. Note that the TSD circuit is provided for the exclusive purpose shutting

down the IC in the presence of extreme heat, and is not designed to protect the IC per se or guarantee performance when

or after extreme heat conditions occur. Therefore, do not operate the IC with the expectation of continued use or

subsequent operation once the TSD is activated.

9. Capacitor between output and GND

When a larger capacitor is connected between the output and GND, Vcc or VIN shorted with the GND or 0V line – for any

reason – may cause the charged capacitor current to flow to the output, possibly destroying the IC. Do not connect a

capacitor larger than 1000uF between the output and GND.

10. Precautions for board inspection

Connecting low-impedance capacitors to run inspections with the board may produce stress on the IC. Therefore, be

certain to use proper discharge procedure before each process of the operation. To prevent electrostatic accumulation and

discharge in the assembly process, thoroughly ground yourself and any equipment that could sustain ESD damage, and

continue observing ESD-prevention procedures in all handling, transfer and storage operations. Before attempting to

connect components to the test setup, make certain that the power supply is OFF. Likewise, be sure the power supply is

OFF before removing any component connected to the test setup.

11. GND wiring pattern

When both a small-signal GND and high current GND are present, single-point grounding (at the set standard point) is

recommended, in order to separate the small-signal and high current patterns, and to be sure the voltage change

stemming from the wiring resistance and high current does not cause any voltage change in the small-signal GND. In the

same way, care must be taken to avoid wiring pattern fluctuations in any connected external component GND.

●Power Dissipation

Ambient Temperature [Ta]

Power Dissipation [Pd]

150 125 100 75 50 25 0

200

400

600

800

1000

[℃]

[mW]

880mW

380mW

70mm×70mm×1.6mm Glass-e

p

ox

y

PCB

θj-a=142.0℃/W

With no heat sink θj-a=328.9℃/W

BD9524MUV

Technical Note

20/20

www.rohm.com 2010.03 - Rev.C

●Ordering part number

B D 9 5 2 4 M U V - E 2

Part No. Part No.

Package

MUV : VQFN032V5050

Packaging and forming specification

E2: Embossed tape and reel

(Unit : mm)

VQFN032V5050

0.08 S

S

1.0MAX

(0.22)

0.02+0.03

-

0.02

24

81

9

32

16

25 17

0.5

0.75

0.4±0.1

3.4±0.1

0.25 +0.05

-

0.04

C0.2

5.0±0.1

1PIN MARK

∗

Order quantity needs to be multiple of the minimum quantity.

Embossed carrier tapeTape

Quantity

Direction

of feed

The direction is the 1pin of product is at the upper left when you hold

reel on the left hand and you pull out the tape on the right hand

2500pcs

E2

()

Direction of feed

Reel 1pin

R1010

A

www.rohm.com

Notice

ROHM Customer Support System

http://www.rohm.com/contact/

Thank you for your accessing to ROHM product informations.

More detail product informations and catalogs are available, please contact us.

Notes

No copying or reproduction of this document, in part or in whole, is permitted without the

consent of ROHM Co.,Ltd.

The content specied herein is subject to change for improvement without notice.

The content specied herein is for the purpose of introducing ROHM's products (hereinafter

"Products"). If you wish to use any such Product, please be sure to refer to the specications,

which can be obtained from ROHM upon request.

Examples of application circuits, circuit constants and any other information contained herein

illustrate the standard usage and operations of the Products. The peripheral conditions must

be taken into account when designing circuits for mass production.

Great care was taken in ensuring the accuracy of the information specied in this document.

However, should you incur any damage arising from any inaccuracy or misprint of such

information, ROHM shall bear no responsibility for such damage.

The technical information specied herein is intended only to show the typical functions of 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 and

other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the

use of such technical information.

The Products specied in this document are intended to be used with general-use electronic

equipment or devices (such as audio visual equipment, ofce-automation equipment, commu-

nication devices, electronic appliances and amusement devices).

The Products specied in this document are not designed to be radiation tolerant.

While ROHM always makes efforts to enhance the quality and reliability of its Products, a

Product may fail or malfunction for a variety of reasons.

Please be sure to implement in your equipment using the Products safety measures to guard

against the possibility of physical injury, re or any other damage caused in the event of the

failure of any Product, such as derating, redundancy, re control and fail-safe designs. ROHM

shall bear no responsibility whatsoever for your use of any Product outside of the prescribed

scope or not in accordance with the instruction manual.

The Products are not designed or manufactured to be used with any equipment, device or

system which requires an extremely high level of reliability the failure or malfunction of which

may result in a direct threat to human life or create a risk of human injury (such as a medical

instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuel-

controller or other safety device). ROHM shall bear no responsibility in any way for use of any

of the Products for the above special purposes. If a Product is intended to be used for any

such special purpose, please contact a ROHM sales representative before purchasing.

If you intend to export or ship overseas any Product or technology specied herein that may

be controlled under the Foreign Exchange and the Foreign Trade Law, you will be required to

obtain a license or permit under the Law.