BD9011KV-E2 - Rohm Semiconductor

TECHNICAL NOTE

Large Current External FET Controller Type Switching Regulator

Step-down,

High-efficiency

Switching Regulators

(Controller type)

BD9011EKN , BD9011KV , BD9775FV

■ BD9011EKN, BD9011KV

●Overview

The BD9011EKN/KV is a 2-ch synchronous controller with rectification switching for enhanced power management efficiency.

It supports a wide input range, enabling low power consumption ecodesign for an array of electronics.

●Features

1) Wide input voltage range: 3.9V to 30V

2) Precision voltage references: 0.8V±1%

3) FET direct drive

4) Rectification switching for increased efficiency

5) Variable frequency: 250k to 550kHz (external synchronization to 550kHz)

6) Built-in selected OFF latch and auto remove over current protection

7) Built-in independent power up/power down sequencing control

8) Make various application , step-down , step-up and step-up-down

9) Small footprint packages: HQFN36V, VQFP48C

●Applications

Car audio and navigation systems, CRTTV，LCDTV，PDPTV，STB，DVD，and PC systems，portable CD and DVD players,

etc.

●Absolute Maximum Ratings (Ta=25℃)

Parameter Symbol Rating Unit Parameter Symbol Rating Unit

EXTVCC Voltage EXTVCC 34

V COMP1,2 Voltage COMP1,2

VCCCL1,2 Voltage VCCCL1,2 34

V DET1,2 Voltage DET1,2

CL1,2 Voltage CL1,2 34 V RT､SYNC Voltage RT､SYNC

VREG5 V

SW1,2 Voltage SW1,2 34

BOOT1,2 Voltage BOOT1,2 40

0.875

（HQFN36V）W

BOOT1,2-SW1,2

Voltage BOOT1,2-SW1,2 7

STB, EN1,2 Voltage STB, EN1,2 VCC V

Power Dissipation Pd

1.1

（VQFP48C）W

VREG5,5A VREG5,5A 7 V Operating

temperature Topr -40 to +105 ℃

VREG33 VREG33 VREG5 V Storage temperature Tstg -55 to +150 ℃

SS1,2､FB1,2 SS1,2､FB1,2 VREG5 V Junction temperature Tj +150 ℃

*1 Regardless of the listed rating, do not exceed Pd in any circumstances.

*2 Mounted on a 70mm x 70mm x 0.8mm glass-epoxy board. De-rated at 7.44mW/℃（HQFN36V） or 8.8mW/℃（VQFP48C）

above 25℃.

Sep. 2008

2/29

●Operating conditions (Ta=25℃)

Parameter Symbol Min. Typ. Max. Unit

Input voltage 1 EXTVCC 3.9

12 30 V

Input voltage 2 VCC 3.9

12 30 V

BOOT－SW voltage BOOT－SW 4.5 5 VREG5 V

Carrier frequency OSC 250 300 550 kHz

Synchronous frequency SYNC OSC - 550 kHz

Synchronous pulse duty Duty 40 50 60 ％

Min OFF pulse TMIN - 100 - nsec

★This product is not designed to provide resistance against radiation.

*1 After more than 4.5V, voltage range.

*2 In case of using less than 6V, Short to VCC, EXTVCC and VREG5.

●Electrical characteristics (Unless otherwise specified, Ta=25℃ VCC=12V STB=5V EN1,2=5V)

Limit

Parameter Symbol

Min. Typ. Max. Unit Conditions

VIN bias current IIN - 5 10 mA

Shutdown mode current IST - 0 10 μA VSTB=0V

［Error Amp Block］

Feedback reference voltage VOB 0.792 0.800 0.808 V

Feedback reference voltage

(Ta=-40 to 105℃) VOB+ 0.784 0.800 0.816 V Ta=-40 to 105℃ ※

Open circuit voltage gain Averr - 46 - dB

VO input bias current IVo+ - - 1 μA

［FET Driver Block］

HG high side ON resistance HGhon - 1.5 - Ω

HG low side ON resistance HGlon - 1.0 - Ω

LG high side ON resistance LGhon - 1.5 - Ω

LG low side ON resistance LGlon - 0.5 - Ω

［Oscillator］

Carrier frequency FOSC 270 300 330 kHz RT=100 kΩ

Synchronous frequency Fsync - 500 - kHz RT=100 kΩ,SYNC=500kHz

［Over Current Protection Block］

CL threshold voltage Vswth 70 90 110 ｍV

CL threshold voltage

（Ta=-40 to 105℃） Vswth+ 67 90 113 ｍV Ta=-40 to 105℃ ※

［VREG Block］

VREG5 output voltage VREG5 4.8 5 5.2 V IREF=6mA

VREG33 reference voltage VREG33 3.0 3.3 3.6 V IREG=6mA

VREG5 threshold voltage VREG_UVLO 2.6 2.8 3.0 V VREG:Sweep down

VREG5 hysteresis voltage DVREG_UVLO 50 100 200 mV VREG:Sweep up

［Soft start block］

Charge current ISS 6.5 10 13.5 μA VSS=1V

Charge current

(Ta=-40 to 105℃) ISS+ 6 10 14 μA VSS=1V,Ta=-40 to 105℃ ※

Note: Not all shipped products are subject to outgoing inspection.

3/29

●Reference data (Unless otherwise specified, Ta=25℃)

Fig.1 Efficiency 1

Fig.4 Reference voltage vs.

temperature characteristics

Fig.5 Over current detection vs.

temperature characteristics

Fig.6 Frequency vs.

tem

erature characteristics

100

0123

OUTPUT CURRENT：Io[A]

EFFICIENCY[%]

1.2V

1.8V 2.6V 3.3V

5.0V

VIN=12V

0.784

0.788

0.792

0.796

0.800

0.804

0.808

0.812

0.816

-40 -15 10 35 60 85 110

AMBIENT TEMPERATURE ： Ta[℃]

RE FE RENC E VOL TAG E ： VO B[V]

100

110

-40 -15 10 35 60 85 110

AMBIENT TEMPERATURE ： Ta[℃]

過電流検出電圧： Vswth[mV]

270

280

290

300

310

320

330

-40 -15 10 35 60 85 110

AMBIENT TEMPERATURE ： Ta[℃]

OSILATING FREQUENCY ： F

OSC

[kHz]

RT=100kΩ

3.00

3.25

3.50

3.75

4.00

4.25

4.50

4.75

5.00

5.25

-40 -15 10 35 60 85 110

AMBIENT TEMPERATURE ： Ta[℃]

OUT PUT VOLTAGE ： Vo[V]

VREG5

VREG33

Fig.7 Internal Reg vs.

tem

erature characteristics

100

6 9 12 15 18 21 24

INPUT VOLTAGE ： V

[V]

EFFICIENCY[%]

3.3V 5.0V

Io=2A

Fig.2 Efficiency 2

0 5 10 15 20 25

INPUT VOL TAG E ： V

[V]

OUT PUT VOLTAGE ： Vo[V]

3.3V

5.0V

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0123456

OUTPUT C URRENT: I o [A]

OUT PUT VOLTAGE ： Vo[V

]

LOFF=

LOFF=H

RCL=15mΩ

Fig.8 Line regulation Fig.9 Load regulation

0246

INPUT VOLTAGE：V

[V]

OUTPUT　VOLTAGE ： Vo[V]

105℃

25℃

-40℃

Fig.10 EN threshold voltage Fig.11 Load transient response 1 Fig.12 Load transient response 2

0102030

INPUT VOLTAGE：V

[V]

CIRC UIT　CURRE NT[ mA]

105℃ 25℃ -40℃

Fig.3 Circuit current

OUT

1A/div

50mV/div

1A/div

50mV/div

4/29

●Block diagram (Parentheses indicate VQFP48C pin numbers)

Fig-13

●Pin configuration ●PIN function table

BD9011EKN（HQFN36V）

Fig-14

No. Pin name Function

1 SW1 High side FET source pin 1

2 DGND1 Low side FET source pin 1

3 OUTL1 Low side FET gate drive pin 1

4 VREG5A FET drive REG input

5 VREG33 Reference input REG output

6 FB1 Error amp input 1

7 COMP1 Error amp output 1

8 SS1 Soft start setting pin 1

9 DET1 FB detector output 1

10 STB Standby ON/OFF pin

11 EN1 Output 1ON/OFF pin

12 EN2 Output 2ON/OFFpin

13 GND Ground

14 LOFF Over current protection OFF latch

function ON/OFF pin

15 RT Switching frequency setting pin

16 SYNC External synchronous pulse input pin

17 LLM Built-in pull-down resistor pin

18 DET2 FB detector output 2

19 SS2 Soft start setting pin 2

20 COMP2 Error amp output 2

21 FB2 Error amp input 2

22 EXTVCC External power input pin

23 － N.C.

24 VREG5 FET drive REG output

25 OUTL2 Low side FET gate drive pin 2

26 DGND2 Low side FET source pin 2

27 SW2 High side FET source pin 2

28 OUTH2 Hi side FET gate drive pin 2

29 BOOT2 OUTH2 driver power pin

30 CL2 Over current detector setting pin 2

31 VCCCL2 Over current detection VCC2

32 VCC Input power pin

33 VCCCL1 Over current detection VCC1

34 CL1 Over current detector setting pin 1

35 BOOT1 OUTH1 driver power pin

36 OUTH1 High side FET gate drive pin 1

OUTH2

BOOT2

CL2

VCCCL2

VCC

VCCCL1

CL1

BOOT1

OUTH1

DET2

LMM

SYNC

LOFF

GND

EN2

EN1

STB

1 2 3

4 5 6 7

8 9

SW1

DGND1

OUTL1

VREG5

VREG33

FB1

COMP1

SS1

DET1

27 26 25

24 23 22 21

20 19

SW2

DGND2

OUTL2

VREG5

EXTVCC

FB2

COMP2

SS2

TSD

5V Reg

2.7V

3.3V Reg

TSD

UVLO

PWM

COMP

Err Amp

0.8V

Sequence DET

UVLO

Ｏ

0.56V 0.56V

VREG5

VCCCL2

CL2

BOOT2

OUTH2

SW2

OUTL2

DGND2

FB2

SS2

COMP2

DET2 LOFF EN2 EN1

VREG5A

EXTVCC STB VCC RT

SYNC

Set

Reset

Reset Set

DRV

Set

Reset

VREG5

OCP

UVLO TSD

B.G SYNC

OSC

Slope

PWM

COMP

TSD

UVLO

Set Reset

DRV

Set

Reset

LOGIC

Set

Reset

Sequence DET

Err Amp

0.8V

OCP

Slope

－

＋

GND DET1

LOGIC

OUTH1

SW1

OUTL1

DGND1

SS1

COMP1

BOOT1

CL1

VCCCL1

VREG33

FB1

5(19)

17(35)

(34)

(7)

(24)

21(39)

24(44)

19(37)

26(47)

33(8)

1(13)

34(10)

36(12)

4(17)

3(15)

2(14)

8(23)

6(21)

7(22)

35(11)

30(3)

31(5)

29(2)

28(1)

27(48)

20(38)

25(46)

(41)

(25)

(33)

(29)

(26)

(27)

(31)

(36) (30)

(GNDS)

LLM

5/29

36 35 34

33 32 31 30

29 28

1 2 3

4 5 6 7

8 9

10 11 12

OUTH2

BOOT2

CL2

N.C

VCCCL2

N.C

VCC

VCCCL1

N.C

CL1

BOOT1

OUTH1

FB1

N.C

VREG33

N.C

VREG5A

N.C

OUTL1

DGND1

SW1

DET1

SS1

COMP1

27 26 25

N.C

EXTVCC

N.C

VREG5

N.C

OUTL2

DGND2

SW2

SS2

COMP2

FB2

DET2

LLM

SYNC

LOFF

GNDS

GND

N.C

EN2

EN1

STB

N.C

●Pin configuration ●Pin function table

BD9011KV（VQFP48C）

Fig-15

●Block functional descriptions

・Error amp

The error amp compares output feedback voltage to the 0.8V reference voltage and provides the comparison result as COMP voltage, which is

used to determine the switching Duty. COMP voltage is limited to the SS voltage, since soft start at power up is based on SS pin voltage.

・Oscillator (OSC)

Oscillation frequency is determined by the switching frequency pin (RT) in this block. The frequency can be set between 250kHz and 550kHz.

・ SLOPE

The SLOPE block uses the clock produced by the oscillator to generate a triangular wave, and sends the wave to the PWM comparator.

・PWM COMP

The PWM comparator determines switching Duty by comparing the COMP voltage, output from the error amp, with the triangular wave from the

SLOPE block. Switching duty is limited to a percentage of the internal maximum duty, and thus cannot be 100% of the maximum.

・Reference voltage (5Vreg，33Vreg)

This block generates the internal reference voltages: 5V and 3.3V.

・External synchronization (SYNC)

Determines the switching frequency, based on the external pulse applied.

・Over current protection (OCP)

Over current protection is activated when the VCCCL-CL voltage reaches or exceeds 90mV. When over current protection is active, Duty is low,

and output voltage also decreases. When LOFF=L, the output voltage has fallen to 70% or below and output is latched OFF. The OFF latch

mode ends when the latch is set to STB, EN.

・Sequence control (Sequence DET)

Compares FB voltage with reference voltage (0.56V) and outputs the result as DET.

・Protection circuits (UVLO/TSD)

The UVLO lock out function is activated when VREG falls to about 2.8V, while TSD turns outputs OFF when the chip temperature reaches or

exceeds 150℃. Output is restored when temperature falls back below the threshold value.

No. Pin name Function

1 OUTH2 High side FET gate drive pin 2

2 BOOT2 OUTH2 driver power pin

3 CL2 Over current detection pin 2

4 N.C Non-connect (unused) pin

5 VCCCL2 Over current detection VCC2

6 N.C Non-connect (unused) pin

7 VCC Input power pin

8 VCCCL1 Over current detection CC1

9 N.C Non-connect (unused) pin

10 CL1 Over current detection setting pin 1

11 BOOT1 OUTH1 driver power pin

12 OUTH1 High side FET gate drive pin 1

13 SW1 High side FET source pin 1

14 DGND1 Low side FET source pin 1

15 OUTL1 Low side FET gate drive pin 1

16 N.C Non-connect (unused) pin

17 VREG5A FET drive REG input

18 N.C Non-connect (unused) pin

19 VREG33 Reference input REG output

20 N.C Non-connect (unused) pin

21 FB1 Error amp input 1

22 COMP1 Error amp output 1

23 SS1 Soft start setting pin 1

24 DET1 FB detector output 1

25 STB Standby ON/OFF pin

26 EN1 Output 1 ON/OFF pin

27 EN2 Output 2 ON/OFF pin

28 N.C Non-connect (unused) pin

29 GND Ground

30 GNDS Sense ground

31 LOFF Over current protection OFF latch

function ON/OFF pin

32 N.C Non-connect (unused) pin

33 RT Switching frequency setting pin

34 SYNC External synchronous pulse input pin

35 LLM Built-in pull-down resistor pin

36 DET2 FB detector output 2

37 SS2 Soft start setting pin 2

38 COMP2 Error amp output 2

39 FB2 Error amp input 2

40 N.C Non-connect (unused) pin

41 EXTVCC External power input pin

42 N.C Non-connect (unused) pin

43 N.C Non-connect (unused) pin

44 VREG5 FET drive REG output

45 N.C Non-connect (unused) pin

46 OUTL2 Low side FET gate drive pin 2

47 DGND2 Low side FET source pin 2

48 SW2 High side FET source pin 2

6/29

●Application circuit example (Parentheses indicate VQFP48C pin numbers)

Fig-16A（Step-Down：Cout=OS Capacitor）

There are many factors(The PCB board layout, Output Current, etc.)that can affect the DCDC characteristics.

Please verify and confirm using practical applications.

Fig-16B（Step-Down：Cout=Ceramic Capacitor）

There are many factors(The PCB board layout, Output Current, etc.)that can affect the DCDC characteristics.

Please verify and confirm using practical applications.

SW1

DGND1

OUTL1

VREG5A

VREG33

FB1

COMP1

SS1

DET1

STB

EN1

EN2

GND

LOFF

SYNC

LLM

SW2

DET2

DGND2

OUTL2

VREG5

EXTVCC

FB2

COMP2

SS2

OUTH1

BOOT1

CL1

VCCCL1

VCC

VCCCL2

CL2

BOOT2

OUTH2

100kΩ

0.1uF

1uF

39kΩ 15000pF

0.1uF

0.33

15mΩ

0.33uF

1uF

39kΩ 15000pF

15kΩ

47kΩ

220uF

(

OS ｺﾝ

)

220uF

(OS ｺﾝ)

13kΩ

68kΩ

10uH Vo(5V/3A)

RB051

L-40

RB051

L-40

10uH Vo(3.3V/3A)

SP8K2 SP8K2

VIN(12V)

(5)

(48)

0.1

uF 0.1

(12)

(11

)

(7)

(3)

(2)

(1)

(47)

(44)

(41)

(39)

(38)

(37)

(36)

(35)

(34)

(33)

(31)

(29)

(27)

(26)

(25)

(13)

(15)

(17)

(19)

(21)

(22)

(24)

(14)

(46)

(23)

100Ω

1nF1nF

100Ω

RB160

VA- 4 0

RB160

VA- 4 0

(8)

(10)

100uF

(SLF12565：TDK)

SW1

DGND1

OUTL1

VREG5A

VREG33

FB1

COMP1

SS1

DET1

STB

EN1

EN2

GND

LOFF

SYNC

LLM

SW2

DET2

DGND2

OUTL2

VREG5

EXTVCC

FB2

COMP2

SS2

OUTH1

BOOT1

CL1

VCCCL1

VCC

VCCCL2

CL2

BOOT2

OUTH2

0.1uF

1uF

1kΩ 10000pF

0.1uF

0.33

23mΩ

0.33uF

1uF

3.3kΩ 3300pF

20kΩ

kΩ

12kΩ

Vo(1.8V/2A)

RB051

L-40

RB051

L-40

10uH Vo(2.5V/2A)

SP8K2 SP8K2

VIN(12V)

(5)

(48)

0.1

uF 0.1

(12)

(11

)

(8)

(7)

(3)

(2)

(1)

(47)

(44)

(41)

(39)

(38)

(37)

(36)

(35)

(33)

(31)

(29)

(13)

(15)

(17)

(19)

(21)

(22)

(24)

(14)

(46)

(23)

100Ω

1nF1nF

100Ω

330pF

15kΩ

150Ω

3300pF

330pF

1000pF

510Ω

10uH

RB160

VA-40

RB160

VA-4 0

(10)

100uF

100kΩ

(34)

(27)

(26)

(25)

30uF

(C2012JB

0J106K

：TDK)

30uF

(C2012JB

0J106K

：TDK)

(SLF10145：TDK)

7/29

Fig-16C（Step-Down：Low Input Voltage）

There are many factors(The PCB board layout, Output Current, etc.)that can affect the DCDC characteristics.

Please verify and confirm using practical applications.

Fig-16D（Step-Up：and Step-Up-Down）

There are many factors(The PCB board layout, Output Current, etc.)that can affect the DCDC characteristics.

Please verify and confirm using practical applications.

Vo(12V/1A)

(36)

(35)

(33)

(31)

(29)

3300pF

10kΩ

SW1

DGND1

OUTL1

VREG5A

VREG33

FB1

COMP1

SS1

DET1

STB

EN1

EN2

GND

LOFF

SYNC

LLM

SW2

DET2

DGND2

OUTL2

VREG5

EXTVCC

FB2

COMP2

SS2

OUTH1

BOOT1

CL1

VCCCL1

VCC

VCCCL2

CL2

BOOT2

OUTH2

0.1uF

1uF

10kΩ 22000pF

0.1uF

0.33

10mΩ

0.33uF

1uF

4.7kΩ22000pF

6.2kΩ

kΩ

220uF

23.5kΩ

Vo(24V/1A)

27uH

SP8K2

VIN(12V)

(48)

1uF 0.1

(12)

(11

)

(7)

(2)

(1)

(47)

(44)

(41)

(39)

(38)

(37)

(13)

(15)

(17)

(19)

(21)

(22)

(24)

(14)

(46)

(23)

100Ω

1nF1nF

100Ω

1000pF

680

kΩ

5.1kΩ

1000pF

220

＊REGSPIC

27uH

RSS

065N03

Co1

RB051L-40

100uF

(10)

(8)

(3)

(5)

RB160

VA-40

RB051

L-40

Co2

Do3

100kΩ

(34)

(27)

(26)

(25)

(SLF12565：TDK)

＊ REGSPIC

Trade Mark of RHOM

SW1

DGND1

OUTL1

VREG5A

VREG33

FB1

COMP1

SS1

DET1

STB

EN1

EN2

GND

LOFF

SYNC

LLM

SW2

DET2

DGND2

OUTL2

VREG5

EXTVCC

FB2

COMP2

SS2

OUTH1

BOOT1

CL1

VCCCL1

VCC

VCCCL2

CL2

BOOT2

OUTH2

0.1uF

1uF

3.3kΩ 4700pF

0.1uF

0.33

23mΩ

0.33uF

1uF

10kΩ 2200pF

20kΩ

12kΩ

VIN(5V)

(5)

(48)

(12)

(11

)

(8)

(7)

(3)

(2)

(1)

(47)

(44)

(41)

(39)

(38)

(37)

(36)

(35)

(33)

(31)

(29)

(13)

(15)

(17)

(19)

(21)

(22)

(24)

(14)

(46)

(23)

100Ω

1nF1nF

100Ω

100pF

33pF

kΩ

30uF

(ｾﾗｺﾝ)

RB051

L-40

6.8uH Vo(2.5V/2A)

SP8K2

1000pF

300Ω

(10)

100uF

100kΩ

(34)

(27)

(26)

(25)

RB160

-40

30uF

(ｾﾗｺﾝ)

Vo(1.8V/2A)

RB051

L-40

SP8K2

15kΩ

100Ω

3300pF

6.8uH 0.1uF

RB160

VA-40 0.1uF

(SLF10145：TDK) (SLF10145：TDK)

8/29

（VCC-VOUT）×VOUT

L×VCC×f

ΔIL = [A]・・・（5）

（VCC-VOUT）×VOUT

ΔIL×VCC×f

L = [H]・・・（7）

Fig-17

VOUT（VCC - VOUT）

VCC

IRMS = IOUT × [A]・・・（10）

●Application component selection

(1) Setting the output L value

The coil value significantly influences the output ripple current.

Thus, as seen in equation (5), the larger the coil, and the higher

the switching frequency, the lower the drop in ripple current.

The optimal output ripple current setting is 30% of maximum current.

ΔIL = 0.3×IOUTmax.[A]・・・（6）

（ΔIL：output ripple current f：switching frequency）

※Outputting a current in excess of the coil current rating will cause magnetic saturation of the coil and decrease

efficiency.

Please establish sufficient margin to ensure that peak current does not exceed the coil current rating.

※Use low resistance (DCR, ACR) coils to minimize coil loss and increase efficiency.

(2) Setting the output capacitor Co value

Select the output capacitor with the highest value for ripple voltage (V

) tolerance and maximum drop voltage

(at rapid load change). The following equation is used to determine the output ripple voltage.

ΔI

Vo 1

Step down ΔV

= ΔI

× R

ESR

+ × × [V] Note: f：switching frequency

Co Vcc f

Be sure to keep the output Co setting within the allowable ripple voltage range.

※Please allow sufficient output voltage margin in establishing the capacitor rating. Note that low-ESR capacitors enable

lower output ripple voltage.

Also, to meet the requirement for setting the output startup time parameter within the soft start time range, please factor

in the conditions described in the capacitance equation (9) for output capacitors, below.

TSS × (Limit – IOUT) Tss： soft start time

Co ≦ ・・・（9）

VOUT ILimit：over current detection value（2/16）reference

Note: less than optimal capacitance values may cause problems at startup.

(3) Input capacitor selection

The input capacitor serves to lower the output impedance of the power

source connected to the input pin (VCC). Increased power supply output

impedance can cause input voltage (VCC) instability, and may negatively

impact oscillation and ripple rejection characteristics. Therefore, be

certain to establish an input capacitor in close proximity to the VCC and

GND pins. Select a low-ESR capacitor with the required ripple current

capacity and the capability to withstand temperature changes without

wide tolerance fluctuations. The ripple current IRMSS is determined

using equation (10).

Also, be certain to ascertain the operating temperature, load range and

MOSFET conditions for the application in which the capacitor will be used,

since capacitor performance is heavily dependent on the application’s

input power characteristics, substrate wiring and MOSFET gate drain

capacity.

VIN

VOUT

Cin

ΔI

Output ripple current

VCC

VOUT

Fig-18

Input capacitor

Fig-19

9/29

Internal ref. 0.8V

(4) Feedback resistor design

Please refer to the following equation in determining the proper feedback resistance. The recommended setting is in a range

between 10kΩ and 330kΩ. Resistance less than 10kΩ risks decreased power efficiency, while setting the resistance value

higher than 330kΩ will result in an internal error amp input bias current of 0.2uA increasing the offset voltage.

R8 +R9

Vo = × 0.8 [V] ・・・（11）

Fig-20

(5) Setting switching frequency

The triangular wave switching frequency can be set by connecting a resistor to the RT 15(33) pin. The RT sets the frequency

by adjusting the charge/discharge current in relation to the internal capacitor. Refer to the figure below in determining proper

RT resistance, noting that the recommended resistance setting is between 50kΩ and 130kΩ. Settings outside this range

may render the switching function inoperable, and proper operation of the controller overall cannot be guaranteed when

unsupported resistance values are used.

250

300

350

400

450

500

550

50 60 70 80 90 100 110 120 130

RT [ kΩ]

周波数 [ kHz ]

Fig-21 RT vs. switching frequency

(6) Setting the soft start delay

The soft start function is necessary to prevent an inrush of coil current and output voltage overshoot at startup. The figure

below shows the relation between soft start delay time and capacitance, which can be calculated using equation (12) at right.

0.8V(typ.)×CSS

TSS = [sec]・・・(12)

ISS(10μA Typ.)

Fig-22 SS capacitance vs. delay time

Recommended capacitance values are between 0.01uF and 0.1uF. Capacitance lower than 0.01uF may generate output

overshoots. Please use high accuracy components (such as X5R) when implementing sequential startups involving other

power sources. Be sure to test the actual devices and applications to be used, since the soft start time varies, depending on

input voltage, output voltage and capacitance, coils and other characteristics.

0.01

0.1

0.001 0.01 0.1

SS CAPACITANCE[uF]

DELAY TIME[ms]

10/29

Over current detection point

COMP

Feedback

VIN

VCCCL

RCL

-18 0

-9 0

18 0

-90

-180

(a)

GBW(b)

-180°

Phase margin

-90°

-20dB/decade

Gain

[dB]

Phase

[deg]

2πRCA

point (a) fa = 1.25[Hz]

2πRC

point (b) fa = GBW [Hz]

(7) Setting over current detection values

The current limit value（ILimit）is determined by the resistance of the RCL established between CL and VCCCL.

90m

ILimit = [A]・・・(13)

RCL

Fig-23 Fig-24

There are 2 current limit function (ON/OFF control type and OFF latch type) toggled by LOFF pin.

・LOFF=L (0<LOFF<1V): Off Latch Type Current Limit

The output becomes OFF and latched when SS=H and, current limit operation, and the output voltage is less than or equal

to 70% of Vo. The OFF latch is deactivated by re-inputting EN signal or VCC control input (switch OFF and ON once more).

・LOFF=H (1<LOFF<VREG5): ON/OFF Control Type Current Limit

When the current goes beyond the threshold value, the current can be limited by reducing the ON Duty Cycle. When the load

goes back to the normal operation, the output voltage also becomes back on to the specific level.

(8) Method for determining phase compensation

Conditions for application stability

Feedback stability conditions are as follows:

・When gain is 1 (0dB) and phase shift is 150° or less (i.e., phase margin is at least 30°):

a dual-output high-frequency step-down switching regulator is required

Additionally, in DC/DC applications, sampling is based on the switching frequency; therefore, overall GBW may be set at no

more than 1/10 the switching frequency. In summary, target characteristics for application stability are:

・Phase shift of 150° or less (i.e., phase margin of 30° or more) with gain of 1 (0dB)

・GBW (i.e., gain 0dB frequency) no more than 1/10 the switching frequency.

Stability conditions mandate a relatively higher switching frequency, in order to limit GBW enough to increase response.

The key to achieving successful stabilization using phase compensation is to cancel the secondary phase margin/delay

(-180°) generated by LC resonance, by employing a dual phase lead. In short, adding two phase leads stabilizes the

application.

GBW (the frequency at gain 1) is determined by the phase compensation capacitor connected to the error amp. Thus, a larger

capacitor will serve to lower GBW if desired.

① General use integrator (low-pass filter) ② Integrator open loop characteristics

Fig-26 Fig-27

The error amp is provided with phase compensation similar to that depicted in figures ① and ② above and thus serves

as the system’s low-pass filter.

In DC/DC converter applications, R is established parallel to the feedback resistance.

LOFF=L

（OFF Latch

）

Vo×70%

LOFF=H

The current limit value

Fig-25

11/29

COMP

2π√LC

fr = [Hz]

Resonance point phase margin -180°

resonance point1

2π√LC

fr = [Hz]：Resonance Point

ESR

= [Hz] :Zero

2πR

ESR

-90°:Pole

Fig-28 Fig-29

Fig-32

2π√LC

When electrolytic or other high-ESR output capacitors are used:

Phase compensation is relatively simple for applications employing high-ESR output capacitors (on the order of several

Ω). In DC/DC converter applications, where LC resonance circuits are always incorporated, the phase margin at these

locations is -180°. However, wherever ESR is present, a 90° phase lead is generated, limiting the net phase margin to -90°

in the presence of ESR. Since the desired phase margin is in a range less than 150°, this is a highly advantageous

approach in terms of the phase margin. However, it also has the drawback of increasing output voltage ripple components.

③ LC resonance circuit ④ ESR connected

Since ESR changes the phase characteristics, only one phase lead need be provided for high-ESR applications. Please choose

one of the following methods to add the phase lead.

⑤ Add C to feedback resistor ⑥ Add R3 to aggregator

Fig-30 Fig-31

Phase lead fz = [Hz] Phase lead fz = [Hz]

Set the phase lead frequency close to the LC resonance frequency in order to cancel the LC resonance.

When using ceramic, OS-CON, or other low-ESR capacitors for the output capacitor:

Where low-ESR (on the order of tens of mΩ) output capacitors are employed, a two phase-lead insertion scheme is

required, but this is different from the approach described in figure ③~⑥, since in this case the LC resonance gives rise

to a 180° phase margin/delay. Here, a phase compensation method such as that shown in figure ⑦ below can be

implemented.

⑦ Phase compensation provided by secondary (dual) phase lead

Phase lead fz1 = [Hz]

Phase lead fz2 = [Hz]

LC resonance frequency fr = [Hz]

Once the phase-lead frequency is determined, it should be set close to the LC resonance frequency.

This technique simplifies the phase topology of the DCDC Converter. Therefore, it might need a certain amount

of trial-and-error process. There are many factors(The PCB board layout, Output Current, etc.)that can affect

the DCDC characteristics. Please verify and confirm using practical applications.

2πC1R1

2πC2R3

Vcc

L C

Vcc

ESR

2πR1C1

2πR3C2

COMP

12/29

Vo1

VCC VREG5 VREG5

OUTH1 BOOT1 VCC BOOT2

SW1

OUTL1

DGND1

FB1

Vo2

COMP1

SS1

DET2

OUTH2

OUTL2

SW2

DGND2

FB2

COMP2

SS2

DET1

STB EN1 EN2 GND

（9）MOSFET selection

FET uses Nch MOS

・V

＞Vcc

・V

GSM1

＞BOOT-SW interval voltage

・V

GSM2

＞VREG5

・Allowable current＞voltage current + ripple current

※Should be at least the over current protection value

※Select a low ON-resistance MOSFET for highest efficiency

Fig-33

（10）Schottky barrier diode selection

・ Reverse voltage V

＞Vcc

・ Allowable current＞voltage current + ripple current

※Should be at least the over current protection value

※Select a low forward voltage, fast recovery diode for highest

efficiency

・ The shoot-through may happen when the input parasitic

capacitance of FET is extremely big or the Duty ratio is less

than or equal to 10%. Less than or equal to 1000pF input

parasitic capacitance is recommended. Please confirm

operation on the actual application since this character is

affected by PCB layout and components.

（11）Sequence function

●Circuit diagram ●Timing chart

Fig-35 Fig-36

GSM1

GSM2

With EN1, 2 at ”H” level, when EN1 goes ”L”,

Vo1 turns OFF, but Vo2 output continues.

When EN1 stays ”H” and EN2 returns to ”H”, DET1 is in

open state; thus SS2 is asserted, and Vo2 output starts.

If Vo2 is 76% of the voltage setting or higher, DET2 goes

open and SS1 is asserted, starting Vo1 output.

EN1

EN2

DET2

SS1

FB1

Vo1

DET1

SS2

FB2

Vo2

0.61V

over 76%

under 70%

0.56V 0.61V 0.56V

over 76%

over 70%

With EN1,2 at “H” level, i

Vo1 starts at 76% or more o

voltage setting, DET goes

open and SS1 is asserted,

starting Vo2 output.

Same as “A” at left

With EN2 set ”L”, if Vo2

goes below 70% the voltage

setting, DET2 shorts and SS1

is asserted, turning Vo1 OFF

Fig-34

13/29

●Input/Output equivalent circuits (Items in parentheses apply to VQFP48C)

1(13)，27(48)PIN（SW1，SW2）

29(2)，35(11)PIN（BOOT2，BOOT1）

28(1)，36(15)PIN（OUTH1，OUTH2）

2(14)，26(47)PIN（DGND1，DGND2）

3(15)，25(46)PIN（OUTL1，OUTL2）

24(44) VREG5 / 4(17)VREG5A

14(31)PIN（LOFF）

16(34)PIN（SYNC） 6(21)，21(39)PIN（FB1，FB2） 8(23)，19(37)PIN（SS1，SS2）

10(25)，11(26)，12(27)PIN

（STB，EN1，EN2） 9(24)，18(36)PIN（DET1，DET2） 15(33)PIN（RT）

17(35)PIN（LLM） 30(3)，34(10)PIN（CL2，CL1）

31(5)，33(8)PIN（VCCCL2，VCCCL1）7(22)，20(38)PIN（COMP1，COMP2）

22(41)PIN（EXTV，CC）

24(44)PIN（VREG5） 5(19)PIN（VREG33） 4(17)DIN（VREG5A）

BOOT

OUTH

300k

OUTL

DGND

LOFF

100k

135.8k

172.2k

VREG5

VREG5A

2.5k

VREG5

/ VREG5A

100k

50k

VCC

STB

EN 172.2k

135.8k

100k DET

VREG5

/ VREG5A

10k

VREG5

SYNC 5k

250k

VREG5

VREG5A

LLM

308k

COMP

VREG5

/ VREG5A

20Ω

5kΩ

VCC

VREG5A

EXTVCC

VREG5

VCC

150k

746.32k

255k

VREG33

VREG5A

VCC

150k

746.32k

469.06k

VCCCL

VCC

14/29

(PINA)

Resistor

Parasitic element

GND

●Operation notes

1）Absolute maximum ratings

Exceeding the absolute maximum ratings for supply voltage, operating temperature or other parameters can damage or

destroy the IC. When this occurs, it is impossible to identify the source of the damage as a short circuit, open circuit, etc.

Therefore, if any special mode is being considered with values expected to exceed absolute maximum ratings, consider

taking physical safety measures to protect the circuits, such as adding fuses.

2）GND electric potential

Keep the GND terminal potential at the lowest (minimum) potential under any operating condition.

3）Thermal design

Be sure that the thermal design allows sufficient margin for power dissipation (Pd) under actual operating conditions.

4）Inter-pin shorts and mounting errors

Use caution when positioning the IC for mounting on printed surface boards. Connection errors may result in damage or

destruction of the IC. The IC can also be damaged when foreign substances short output pins together, or cause shorts

between the power supply and GND.

5）Operation in strong electromagnetic fields

Use caution when operating in the presence of strong electromagnetic fields, as this may cause the IC to malfunction.

6）Testing on application boards

Connecting a capacitor to a low impedance pin for testing on an application board may subject the IC to stress. Be sure to

discharge the capacitors after every test process or step. Always turn the IC power supply off before connecting it to or

removing it from any of the apparatus used during the testing process. In addition, ground the IC during all steps in the

assembly process, and take similar antistatic precautions when transporting or storing the IC.

7) The output FET

The shoot-through may happen when the input parasitic capacitance of FET is extremely big or the Duty ratio is less than

or equal to 10%. Less than or equal to 1000pF input parasitic capacitance is recommended. Please confirm operation on

the actual application since this character is affected by PCB layout and components.

8）This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated.

P-N junctions are formed at the intersection of these P layers with the N layers of other elements, creating a parasitic diode

or transistor. Relations between each potential may form as shown in the example below, where a resistor and transistor

are connected to a pin:

○ With the resistor, when GND＞ Pin A, and with the transistor (NPN), when GND＞Pin B:

The P-N junction operates as a parasitic diode

○ With the transistor (NPN), when GND＞ Pin B:

The P-N junction operates as a parasitic transistor by interacting with the N layers of elements in proximity to the

parasitic diode described above.

Parasitic diodes inevitably occur in the structure of the IC. Their operation can result in mutual interference between circuits,

and can cause malfunctions, and, in turn, physical damage or destruction. Therefore, do not employ any of the methods

under which parasitic diodes can operate, such as applying a voltage to an input pin lower than the (P substrate) GND.

Fig-37 Fig-38 Fig-39 Fig-40

9）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 voltage changes stemming

from the wiring resistance and high current do 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.

(PINB)

Transistor（NPN）

N N

P substrate

GND

C E

Parasitic element or transistor

GND

Parasitic element or transisto

(PINB)

(PINA)

Parasitic element

15/29

10）In some application and process testing, Vcc and pin potential may be reversed, possibly causing internal circuit or element

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, limiting output pin capacitance to 100μF or less and inserting a Vcc series countercurrent

prevention diode or bypass diode between the various pins and the Vcc is recommended.

Fig-41

11）Thermal shutdown (TSD)

This IC is provided with a built-in thermal shutdown (TSD) circuit, which is designed to prevent thermal damage to or

destruction of the IC. Normal operation should be within the power dissipation parameter, but if the IC should run beyond

allowable Pd for a continued period, junction temperature (Tj) will rise, thus activating the TSD circuit, and turning all output

pins OFF. When Tj again falls below the TSD threshold, circuits are automatically restored to normal operation. Note that

the TSD circuit is only asserted beyond the absolute maximum rating. Therefore, under no circumstances should the TSD

be used in set design or for any purpose other than protecting the IC against overheating

12）The SW pin

When the SW pin is connected in an application, its coil counter-electromotive force may give rise to a single electric

potential. When setting up the application, make sure that the SW pin never exceeds the absolute maximum value.

Connecting a resistor of several Ω will reduce the electric potential. (See Fig. 43)

Fig-42

13）Dropout operation

When input voltage falls below approximately output voltage / 0.9 (varying depending on operating frequency) the ON

interval on the OUTL side MOS is lost, making boost applications and wrap operation impossible. If a small differential

between input and output voltage is envisioned for a prospective application, connect the load such that the SW voltage

drops to the GND level. Managing this load requires discharging the SW line capacitance (SW pin capacitance: approx.

500pF; OUTL side MOS D-S capacitance; Schottky capacitance). Supported loads can be calculated using the equation

below.

Output voltage × SW line capacitance

ILOAD =

25n

Note that SW line capacitance is lower with smaller loads, and more stable operation is attained when low voltage bias

circuits are configured as in the example below (Fig. 44). However, the degree to which line capacitance is reduced or

operational stability is attained will vary depending on the board layout and components. Therefore, be certain to confirm

the effectiveness of these design factors in actual operation before entering mass production.

Fig-43

Vcc

Bypass diode

Countercurrent prevention diode

OUT

Vcc

VREG

OUT

BOOT

DGND

OUTL

OUTH

SW R

Vcc

16/29

HQFN36V

0.0

0.2

0.4

0.6

0.8

1.0

0 25 50 75 100 125 150

AMBIENT TEMPERATORE：Ta [℃]

POWER DISSIPATION：Pd [W]

PD(W)

②0.875W

①0.56W

VQFP48C

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 25 50 75 100 125 150

AMBIENT TEMPERATORE：Ta [℃]

POWER DISSIPATION：Pd [W]

PD(W)

②1.1W

①0.75W

●Power dissipation vs. temperature characteristics

①：Stand-alone IC ①：Stand-alone IC

②：Mounted on Rohm standard board ②：Mounted on Rohm standard board

（70mm x 70mm x 1.6mm glass-epoxy board ）（70mm×70mm×1.6mm glass-epoxy board）

●Part order number

B D 9 0 1 1 K V － E 2

ROHM part

code

Type/No. Package type

KV ： VQFP48C

EKN ： HQFN36V

Tape and Reel Information

E2 : Embossed carrier tape

HQFN36V

（Unit:mm）

(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)

Tape

Quantity

Direction

of feed

Embossed carrier tape(with dry pack)

2500pcs

※When you order , please order in times the amount of package quantity.

Reel Direction of feed

1pin

1234

（Unit:mm)

VQFP48C

< Packing information >

※When you order , please order in times the amount of package quantity.

Quantit

Direction

of feed

Embossed carrier tape

1500pcs

(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)

Reel 1Pin Direction of feed

17/29

■BD9775FV (1channel synchronous rectification configuration)

●Description

BD9775FV is Switching Controller with synchronous rectification(BD9775FV is 1channel synchronous rectification) and wide

input range. It can contribute to ecological design(lower power consumption) for most of electronic equipments.

●Features (BD9775FV)

1) 2channel Step-Down DC/DC FET driver

2) Synchronous rectification for channel 2

3) Able to synchronize to an external clock signal

4) Over Current Protection (OCP) by monitoring VDS of P channel FET

5) Short Circuit Protection (SCP) by delay time and latch method

6) Under Voltage Lock Out (UVLO)

7) Thermal Shut Down (TSD)

8) Package : SSOP-B28

●Applications (BD9775FV)

Car navigation system, Car Audio, Display, Flat TV

●Absolute maximum ratings (Ta=25℃)(BD9775FV)

Parameter Symbol Limits Units

Supply Voltage (VCC to GND) Vcc 36 V

VREF to GND Voltage Vref 7 V

VREGA to GND Voltage Vrega 7 V

VREGB to VCC Voltage Vregb 7 V

OUT1, OUT2H to VCC Voltage Vouth 7 V

OUT2L to GND Voltage Voutl 7 V

Power Dissipation Pd 640(*1) mW

Operating Temperature Range Topr -40 to +85 ℃

Storage Temperature Range Tstg -55 to +125 ℃

Junction Temperature Tjmax +125 ℃

(*1) Without heat sink, reduce to 6.4mW when Ta=25℃ or above

Pd is 850mW mounted on 70x70x1.6mm, and reduce to 8.5mW/℃ above 25℃.

18/29

●Recommended operating conditions（Ta=-25 to +75℃）(BD9775FV)

●Electrical characteristics （Ta = 25℃，VCC=13.2V, fosc=100kHz, CTL1=3V, CTL2=3V）(BD9775FV)

Limits

Parameter Symbol

Min. Typ. Max.

Unit Condition

【Whole Device】

Stand-by Current Iccst －－ 5 μA CTL1,CTL2=0V

Circuit Current Icc 2.5 4.2 7 mA FB1,FB2=0V

【Reference Voltage】

VREF Output Voltage Vref 2.97 3.00 3.03 V Io=-1mA

Line Regulation DVli －－ 10 mV Vcc=7 to 18V,Io=-1mA

Load Regulation DVlo －－ 10 mV Io=-0.1mA to -2mA

Short Output Current Ios -60 -22 -5 mA

【Internal Voltage Regulator】

VREGA Output Voltage Vrega 4.5 5.0 5.5 V Switching with COUT=5000pF

VREGB Output Voltage Vregb VCC-5.5 VCC-5.0 VCC-4.5 V Switching with COUT=5000pF

VREGB Dropout Voltage Vdregb － 1.8 2.2 V VREGB to GND Voltage

【Oscillator】

Oscillating Frequency fosc 90 100 110 kHz RT=27kΩ,CT=470pF

Frequency Tolerance Dfosc －－ 2 % Vcc=7 to 18V

【Synchronized Frequency】

Synchronized Frequency ｆosc2 － 120 － kHz FIN=120kHz

FIN Threshold Voltage Vthfin 1.2 1.4 1.6 V

FIN Input Current IFIN -1 － 1 μA VFIN=1.4V

【Error Amplifier】

Threshold Voltage Vthea 0.98 1.00 1.02 V

INV Input Bias Current Ibias -1 － 1 μA

Voltage Gain Av － 70 － dB DC

Band Width Bw － 2.0 － MHz Av=0dB

Maximum Output Voltage Vfbh 2.2 2.4 2.6 V INV=0.5V

Minimum Output Voltage Vfbl －－ 0.1 V INV=1.5V

Output Sink Current Isink 0.5 2 5.2 mA FB1,2 Terminal

Isource1 -170 -110 -70 μA FB1 Terminal

Output Source Current

Isource2 -200 -130 -85 μA FB2 Terminal

Limits

Parameter Symbol

MIN TYP MAX

Units

Supply Voltage VCC 6.0 - 30.0 V

Oscillating Frequency ｆosc 30 100 300 KHz

Timing Resistance RT 10 27 56 KΩ

Timing Capacitance CT 100 470 4700 pF

19/29

Limits

Parameter Symbol

Min. Typ. Max.

Unit Condition

【PWM Comparator】

Threshold Voltage at 0% Vth0 0.88 0.98 1.08 V FB Voltage

Threshold Voltage

at 100%

Vth100 1.88 1.98 2.08 V FB Voltage

DTC Input Bias Current Idtc -1 － 1 μA

【FET Driver】

Sink Current Isink 20 36 58 mA VDS=0.4V

Source Current Isource -510 -320 -180 mA VDS=0.4V

RonN 7.0 11.0 17.8 Ω OUT1,2H,2L : L

ON Resistance

RonP 0.7 1.4 2.2 Ω OUT1,2H,2L : H

Rise Time Tr － 20 － nsec Switching with COUT=5000pF

Fall Time Tf － 100 － nsec Switching with COUT=5000pF

Driver’s Duty Cycle of

Synchronous

Rectification

ΔDuty 42 45 48 %

RSYNC=30KΩ,

50% of main driver’s duty cycle

SYNC Terminal Voltage Vsync 1.45 1.55 1.65 V Rsync=30KΩ,FB=1.5V

【Over Current Protection (OCP)】

VS Threshold Voltage Vths VCC-0.24 VCC-0.21 VCC-0.18 V

RCL=21kΩ, the output tern off after

detected 8 cycle

IVSH -1 － 1 μA VS1,VS2=PBU

VS Input Current

IVSL -1 － 1 μA VS1,VS2=0V

CL Input Current Icl 9 10 11 μA

【Stand-by】

Threshold Voltage Vctl 1.0 1.5 2.0 V

CL Input Current Ictl 6 15 30 μA CTL1,CTL2=3V

【Short Circuit Protection （SCP）】

Timer Start Voltage Vtime 0.6 0.7 0.8 V INV Voltage

Threshold Voltage Vthscp 1.92 2.00 2.08 V SCP Voltage

Stand-by Voltage Vstscp － 10 100 mV SCP Voltage

Source current Isoscp -4.0 -2.5 -1.5 μA SCP=1.0V

【Under Voltage Lock Out （UVLO）】

Threshold Voltage Vuvlo 5.6 5.7 5.8 V Vcc sweep down

Hysteresis

Voltage Range

DVuvlo 0.05 0.1 0.15 V

20/29

● Pin Description ●PinNo/PinName (BD9775FV)

(BD9775FV)

●Block Diagram (BD9775FV)

Fig.1

●FUNCTION EXPLANATION (BD9775FV)

1.DC/DC Converter

・Reference Voltage

Stable voltage of compensated temperature, is generated from the power supply voltage (VCC). The reference voltage is 3.0V,

the accuracy is ±1％. Place a capacitor with low ESR (several decades mΩ) between VREF and GND.

・Internal Regulator A （VREGA）

5V is generated the power supply voltage. The voltage is for the driver of the synchronous rectification’s MOSFET. Place a

capacitor with low ESR (several decades mΩ) between VREGA and PGND.

No.

Name Description

1 FB1

Error amplifier output pin（Channel 1）

2 INV1

Error amplifier negative input pin（Channel 1）

3 RT

Oscillator frequency adjustment pin

connected resistor

4 CT

Oscillator frequency adjustment pin

connected capacitor

5 FIN Oscillator synchronization pulse signal input pin

6 GND Low-noise ground

7 VREF Reference voltage output pin

8 DTC1

Maximum duty and soft start adjustment

pin（Channel 1）

9 DTC2

Maximum duty and soft start adjustment

pin（Channel 2）

10 INV2 Error amplifier negative input pin（Channel 2）

11 FB2

Error amplifier output pin（Channel 2）

12 CTL1 Enable/stand-by control input（Channel 1）

13 CTL2 Enable/stand-by control input（Channel 2）

14 VCC Main power supply pin

15 SYNC Synchronous rectification timing adjustable pin

16 PGND Power ground (connected low-side gate driver

and digital ground)

17 OUT2L Low-side ( synchronous rectifier ) gate driver

output pin（Channel 2）

18 VREGA Connected capacitor for internal regulator

19 SCP Delay time of short circuit protection adjustment

pin connected capacitor

20 VS2 Over current detection voltage monitor pin

（connected FET drain, Channel 2）

21 CL2 Over current detection voltage adjustment pin

connected capacitor and resistor（Channel 2）

22 PVCC2 High-side gate driver power supply

input（Channel 2）

23 OUT2H High-side gate driver output pin（Channel 2）

24 VREGB Connected capacitor for internal regulator

25 OUT1 High-side gate driver output pin（Channel 1）

26 PVCC1 High-side gate driver power supply

input（Channel 1）

27 CL1 Over current detection voltage adjustment pin

connected capacitor and resistor（Channel 1）

28 VS1 Over current detection voltage monitor pin

（connected FET drain, Channel 1）

FB1

INV1

Fin

GND

VREF

DTC1

DTC2

INV2

FB2

VS1

CL1

PVCC1

OUT1

VREGB

OUT2H

PVCC2

CL2

VS2

SCP

VREGA

CTL1

CTL2

VCC

OUT2L

PGND

SYNC

21/29

・Internal regulator B （VREGB）

(VCC-5V) is generated from the power supply voltage. The voltage is for the driver of the main MOSFET switch.

Place a capacitor with low ESR (several decades mΩ) between VREGB and PVCC.

・Oscillator

Placing a resistor and a capacitor to RT and CT, respectively, generates two triangle waves for both cannels, and each wave

is opposite phase. The waves are input to the PWM comparators for CH1 and CH2. Also, the oscillating frequency can be

slightly adjusted (less than 20%) by putting external clock pulse into Fin pin, which is higher frequency than the fixed one.

・Error Amplifier

It amplifies the difference, between the establish output voltage and the actual output one detected at INV. And amplified

voltage comes out from FB. The comparing voltage is 1.0V and the accuracy is ±2%. The phase can be compensated

externally by placing a resistor and a capacitor between INV and FB.

・PWM Comparator

It converts the output voltage from error amplifier into PWM waveform, then output to MOSFET driver.

・MOSFET Driver

The main drivers (OUT1, OUT2H) are for P-channel MOSFETs, and the driver (OUT2L) for synchronous rectification is for

N-channel MOSFET. The values of output voltage are clamp to VREGB, VREGA, respectively. All drivers’ output

configurations are push-pull type. In addition, the output current capability is 36mA for the sink current and 320mA

(Vds=0.4V) for the source current.

2.Channel Control

Each output can be individually turned on or off with CTL1 and CTL2. When the CTL is “H” (more than 1.5V), it becomes

turned on.

3.Protection

・Over Current Protection（OCP）

When detected over current (detecting drop voltage of the main MOSFET’s ON resistance), the MOSFET switch becomes

turned off, and the energy on DTC pin is discharged. After discharged, the output restarts automatically. The level of the

OCP detection threshold can be set by the resistance, which is connected between VCC and CL.

・Short Circuit Protection（SCP）

When either output goes down and the voltage on INV pin gets lower than 0.7V, a capacitor placed on SCP is started to

charge.

When the SCP pin becomes more than 2.0V, the main MOSFET switches of both outputs are turned off; then, the outputs are

latched. While they are latched, the IC can be reset by restarting VCC or CTL, or discharging SCP.

・Under Voltage Lock Out（UVLO）

Due to avoiding malfunctions when the IC is started up or the power supply voltage is rapidly disconnected, the main

MOSFET switches become off and DTC is discharged when the supply voltage is less than 5.7V. Also, when the output is

latched because of SCP function, the latch becomes reset. Due to preventing malfunctions in the case the power supply

voltage fluctuate at near UVLO threshold, there is 0.1V hysteresis between the detection and reset voltage of UVLO

threshold.

・Thermal Shut Down（TSD）

Due to preventing breakdown of the IC by heating up, the main MOSFET switches become off and DTC pin is discharged by

detecting over temperature of the chip. Due to preventing malfunctions in the case temperature fluctuate at near TSD

threshold, there is hysteresis between TSD on and off.

22/29

●SETTING UP INFOMATION (BD9775FV)

1)Simultaneously OFF Duty of MOSFETs for Synchronous Rectification

The simultaneously OFF duty of both main MOSFET switch and synchronous rectification MOSFET is determined by

resistance (Rsync) between SYNC and GND. See Fig. 4.

In Synchronous Rectification, insert RFB2-GND (RFB2-GND≒3×Rsync) between FB2 and GND, because it is possible to

reduce overshoot(sea fig.2). RFB2-GND decide following formula.

Fig.2

・Resistance at FB2-GND setup condition

※Rsync(MAX)…MAX dispersion range at Rsync Rsync(MIN)…MIN dispersion range at Rsync

Short SYNC to VREF if the synchronous rectification function is not needed.

Without Synchronous Rectification（Don’t insert R

FB2-GND

）

0 20406080100

Rsync (kΩ)

ΔDuty (%)

T=-40℃

T= 25℃

T=105℃

SYNC

VREF

fosc=100kHz

Δduty=(t1+t2)/t×100 (%)

OUT2H

OUT2L

t1 t2

Threshold Voltage at100%

-Out

ut Source Current at FB2

Vsync

3×Rsync(MAX)

FB2-GND

< 3xRsync(MIN)

2.08

0.4908

Rsync(MAX) +80.7x10

-6

FB2-GND

< < 3xRsync(MIN)

Rsync

SYNC FB2 R

FB2-GND

23/29

2) Oscillator Synchronization by External Pulse Signal

At the operation the oscillator is externally synchronized, input the synchronization signal into Fin in addition to connect a

resistor and a capacitor at RT and CT, respectively.

Input the external clock pulse on Fin, which is higher frequency than the fixed one. However, the frequency variation

should be less than 20%.

Also, the duty cycle of the pulse should be set from 10% to 90%.

CT Waveform during Synchronized with External Pulse

Short Fin to GND if the function of external synchronization is not needed.

Without Synchronization Signal

3)Setting the Over Current Threshold Level

The OCP detection level（Iocp）is determined by the ON resistance (R

) of the main MOSFET switch and the resistance

(Rcl) which is placed between CL and VCC.

Iocp ＝ ×10

-5

[A] （typ.）

To prevent a malfunction caused by noise, place a capacitor（Ccl） parallel to Rcl.

If OCP function is not needed, short VS to VCC, and short CL to GND.

With OCP Without OCP

CL, VS Pin Connection

Rcl

Fin

： Fixed with RT and CT

： Synchronized

VCC

Rcl

VCC

Ccl

To Main MOSFET Drain

24/29

4)Setting the Time for Short Circuit Protection

The time (tscp) from output short to latch activation is determined by the capacitor, Cscp, connected SCP pin.

tscp

＝

7.96

Cscp

[sec]

（

typ.

）

Short SCP to GND if SCP function is not being used.

Without SCP

5)Single Channel Operation

This device can be used as a single output. The connection is as follows;

DTC,FB,CTL,CL Short to GND

VS,PVCC Short to VCC

INV Short to VREF

Single Channel Operation

6)Setting the Oscillating Frequency

The oscillating frequency can be set by selecting the timing resistor (RRT)and the timing capacitor (CCT).

Fig.3

Fig.4

Ocsillating Frequency vs. Timing Capacitance (CCT)

100

1000

10 100 1000

Timing Resistance (kΩ)

Oscillating Frequency (kHz)

=470pF

=1000pF

=100pF

SCP

Ocsillating Frequency vs. Timing Capacitance (RRT)

100

1000

100 1000 10000

Timing Capacitan ce(pF)

Oscillating Frequency (kHz)

=100kΩ

=27kΩ

=5.1kΩ

DTC

CTL

PVCC

INV

VREF

VCC

25/29

●

Timing Chart (BD9775FV)

・

Output ON/OFF, Minimum Input

（

UVLO

）

Fig.5

・

Over Current Protection, Short Circuit Protection, Thermal Shut Down

Fig.6

●

I/O EQUIVALENT CIRCUIT (BD9775FV)

FB1(1) FB2(11) RT(3)

VREF VREGA VCC

FB1

VREF VREGA VCC

VREF

VCC

INV1(2),INV2(10) CT(4) FIN(5)

VCC

VREF

INV1,2

VREF VCC

VREG VCC

FIN

Fig.8

VCC

CTL1

CTL2

DTC1

DTC2

Vout1

Vout2

6.0V UVLO is inactivated

at 5.8V

Stand-by Soft start

1.0V

UVLO is activated at 5.7V

CTL1,2

SCP

DTC1,2

Vout1,2

Iout1,2

OCP is activated by detecting 8 consecutive cycles

OCP detection level

1.0V

2.0V

Half short of output

ctivate SCP

Inactivate half-short

Reset the latch by restarting CTL

ctivate TSD Inactivate TSD

0.7×fixed output voltage

VCC

FB1

VREGA

VREF

VCC

VREGA

VREF

VCC

VREF

INV1，2

VCC

VREF

VCC

VREF

VCC

VREF

FIN

26/29

DTC1(8),DTC2(9) CTL1(12),CTL2(13) SYNC(15)

VREGA VREF

DTC1,2

VCC

VCCVREGA

CTL1,2

VREF VCC

SYNC

SCP(19) OUT2L(17),VREGA(18) VREF(7)

VCC

SCP

VREF

VCC

VREGA

OUT2L

～

VREF

PVCC1(26),PVCC2(22)

OUT1(25),OUT2H(23),VREGB(24) VS1(28),VS2(20),CL1(27),CL2(21)

VCC

PVCC1,2

OUT1,2H

VREGB

CL1,2

S1,2

●

Operation Notes (BD9775FV)

1) Absolute maximum ratings

Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range may result in IC deterioration

or damage. Assumptions should not be made regarding the state of the IC (short mode or open mode) when such damage is suffered.

A physical safety measure such as a fuse should be implemented when use of the IC in a special mode where the absolute maximum ratings

may be exceeded is anticipated.

2) GND potential

Ensure a minimum GND pin potential in all operating conditions. In addition, ensure that no pins other than the GND pin carry a voltage lower

than or equal to the GND pin, including during actual transient phenomena.

3) Thermal design

Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions.

4) Inter-pin shorts and mounting errors

Use caution when orienting and positioning the IC for mounting on printed circuit boards. Improper mounting may result in damage to the IC.

Shorts between output pins or between output pins and the power supply and GND pin caused by the presence of a foreign object may result in

damage to the IC.

5) Operation in a strong electromagnetic field

Use caution when using the IC in the presence of a strong electromagnetic field as doing so may cause the IC to malfunction.

6) Thermal shutdown circuit (TSD circuit)

This IC incorporates a built-in thermal shutdown circuit (TSD circuit). The TSD circuit is designed only to shut the IC off to prevent runaway

thermal operation. Do not continue to use the IC after operating this circuit or use the IC in an environment where the operation of the thermal

shutdown circuit is assumed.

7) Testing on application boards

When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to stress. Always discharge

capacitors after each process or step. Ground the IC during assembly steps as an antistatic measure, and use similar caution when transporting

or storing the IC. Always turn the IC's power supply off before connecting it to or removing it from a jig or fixture during the inspection process.

8) Common impedance

Power supply and ground wiring should reflect consideration of the need to lower common impedance and minimize ripple as much as possible

(by making wiring as short and thick as possible or rejecting ripple by incorporating inductance and capacitance).

VCC

VREGA VREF

DTC1,2

VCC

VREF

SCP

VCC

PVCC1，2

OUTH1，2H

VREGB

VCC

VS1，2

CL1，2

VCC

VREF

VCC

VREGA

OUT2L

VCC

VREGA

CTL1，2

VREF VCC

SYNC

27/29

Vcc

Bypass diode

Countercurrent

prevention diode

9) Applications with modes that reverse VCC and pin potentials may cause

damage to internal IC circuits.

For example, such damage might occur when VCC is shorted with the

GND pin while an external capacitor is charged.

It is recommended to insert a diode for preventing back current flow

in series with VCC or bypass diodes between VCC and each pin.

Fig.9

10) Timing resistor and capacitor

Timing resistor(capacitor) connected between RT(CT) and GND, has to be placed near RT(CT) terminal 3pin(4pin). And pattern has to be short

enough.

11) The Dead time input voltage has to be set more than 1.1V.

Also, the resistance between DTC and VREF is used more than 30kΩ to work OCP function reliably.

12) The energy on DTC1（8pin）and DTC2（9pin）is discharged when CTL1（12pin）and CTL2（13pin）are OFF, respectively, or VCC（14pin）

is OFF (UVLO activation). However, it is considerable to occur overshoot when CTL and VCC are turned on with remaining more than 1V on

the DTC.

13) If Gate capacitance of P-channel MOSFET or resistance placed on

Gate is large, and the time from beginning of Gate switching to the end of Drain’s (tsw),

is long, it may not start up due to the OCP malfunction.

To avoid it, select MOSFET or adjust resistance as tsw becomes less than 270nsec.

Fig.10

14) IC pin input

This monolithic IC contains P+ isolation and PCB layers between adjacent elements in order to keep them isolated.

P/N junctions are formed at the intersection of these P layers with the N layers of other elements to create a variety

of parasitic elements. For example, when a resistor and transistor are connected to pins as shown in following chart,

○the P/N junction functions as a parasitic diode when GND > (Pin A) for the resistor or GND > (Pin B) for the transistor (NPN).

○Similarly, when GND > (Pin B) for the transistor (NPN), the parasitic diode described above combines with the N layer of other adjacent

elements to operate as a parasitic NPN transistor.

The formation of parasitic elements as a result of the relationships of the potentials of different pins is an

inevitable result of the IC's architecture. The operation of parasitic elements can cause interference with circuit

operation as well as IC malfunction and damage. For these reasons, it is necessary to use caution so that the IC is

not used in a way that will trigger the operation of parasitic elements, such as by the application of voltages lower

than the GND (PCB) voltage to input and output pins.

Fig.11

Fig.12

VCC

VREF

tsw

GATE

DRAIN

②Copper laminate area 70 mm×70mm

①With no heat sink

0.4

0.6

0.2

050 75 100 125025

AMBIENT TEMPERATURE ： Ta(℃)

pd(W)

0.8

①0.587W

①0.64W

POWER DISSIPATION ： pd(W）

1.0

②0.85W

150

(PINA)

Resistor

Parasitic element

GND

(PINB)

Transistor（NPN）

N N

P substrate

GND

C E

Parasitic element or transistor

GND

Parasitic element or transisto

(PINB)

(PINA)

Parasitic element

28/29

●

Part order number

B D 9 7 7 5 F V - E 2

ROHM Part

Code

Type/No. Package type

FV : SSOP-B28

Tape and Reel Information

E2 : Embossed carrier tape

(

Unit:mm

)

SSOP-B28

<Dimension> <Ta

e and Reel information>

uantit

Direction

of feed

Embossed carrier ta

2000

(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)

Reel

Direction of feed

1234

123

1234

123

1234

※When you order , please order in times the amount of package quantity.

Appendix-Rev4.0

Thank you for your accessing to ROHM product informations.

More detail product informations and catalogs are available, please contact your nearest sales office.

ROHM Customer Support System THE AMERICAS / EUROPE / ASIA / JAPAN

www.rohm.com

FAX : +81-75-315-0172

Appendix

Notes

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The content specified 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 specifications, 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 specified in this document. However, should

you incur any damage arising from any inaccuracy or misprint of such information, ROHM shall bear no re-

sponsibility for such damage.

The technical information specified herein is intended only to show the typical functions of and examples

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use or exercise intellectual property or other rights held by ROHM and other parties. ROHM shall bear no re-

sponsibility whatsoever for any dispute arising from the use of such technical information.

The Products specified in this document are intended to be used with general-use electronic equipment

or devices (such as audio visual equipment, office-automation equipment, communication devices, elec-

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The Products 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, fire or any other damage caused in the event of the failure of any Product, such as

derating, redundancy, fire 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

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