BD9421F_15_技术文档

Datasheet

LED Drivers for LCD Backlights

White LED Driver for large LCD Panels

(DCDC Converter Type)

BD9421F

General Description

Key Specifications

BD9421F is high efficiency driver for white LED. This is

designed for large sized LCD. BD9421F is built-in

DCDC converters that supply appropriate voltage for

light source.



VCC Supply Voltage Range:

9.0V to 35.0V

DCDC Oscillation Frequency:150kHz(RT=100kΩ)

Operation Circuit Current:

Operating Temperature Range:

5mA(Typ)

-40°C to +85°C

BD9421F is also built-in protection function for

abnormal state such as OVP: over voltage protection,

OCP: over current limit protection of DCDC, SCP: short

circuit protection, open detection of LED string.

Thus this is used for conditions of large output voltage

and load conditions.

Applications

 LED driver for TV, Monitor and LCD Back Light

Package

W(Typ) x D(Typ) x H(Max)

15.00mm x 7.80mm x 2.01mm

Pin Pitch 1.27mm

SOP24

Features



6ch LED constant current driver(External PNP Tr

Type)



Maximum LED setting current 500mA(VREF Pin

setting)

 ±2% LED current accuracy(VREF=0.9V setting)



Built-in DC/DC converter

Analog Dimming(Linear) function

LED protection function(OPEN/SHORT

protection)[PWM-independent Type]

Individual detection and individual LED OFF for both

OPEN and SHORT circuit

VOUT Over Voltage Protection(OVP) and reduced

voltage protection(SCP) circuit



Built-in under voltage lockout function(UVLO) and

over voltage protection(OVP)

Figure 1. SOP24

Built-in VOUT discharge circuit while shutdown

Typical Application Circuit

Figure 2. Typical Application Circuit

〇Product structure : Silicon monolithic integrated circuit 〇This product has no designed protection against radioactive rays

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BD9421F

Absolute Maximum Ratings(Ta = 25°C)

Parameter

Symbol

Rating

Unit

Supply Voltage

VCC

STB,OVP

BS1-6

-0.3 to +36

-0.3 to +60

-0.3 to +7

-0.3 to +14

-0.3 to +20

0.68 ^{(Note 1)}

-40 to +85

-55 to +150

150

V

STB,OVP Voltage

BS1-6 Voltage

V

CS,CL1-6,FB,RT Voltage

REG75,N Voltage

CS,CL1-6,FB,RT

REG75,N

PWM,VREF

Pd

V

PWM,VREF Voltage

V

Power Dissipation for SOP24

Operating Temperature Range

Storage Temperature Range

Maximum Junction Temperature

W

°C

Topr

Tstg

Tjmax

(Note 1) Derating in done 5.5mW/°C for operating above Ta≧25°C (Mount on 1-layer 70.0mm x 70.0mm x 1.6mm board)

Caution: Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit

between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated over

the absolute maximum ratings.

Recommended Operating Conditions(Ta= -40°C to +85°C)

Parameter

Supply Voltage

Symbol

Min

Typ

Max

Unit

VCC

FSW

VREF

9

24

-

35

800

3.0

V

kHz

V

DC/DC Oscillation Frequency

100

0.6

Analog Dimming Setting Input Range

0.9

External Component Recommended Range

Parameter

Symbol

Specification

Unit

VCC pin connecting capacity

CVCC

C_REG

RRT

1 to 100

1.0 to 10

uF

kΩ

REG75 pin connecting capacity

RT pin connection resistance range

18.75 to 150

The operating conditions listed above are constants for the IC alone. To make constant setting with practical set devices, utmost attention should be paid.

Pin Configuration

Marking Diagram and Physical Dimension

(TOP VIEW)

BD9421F

1PIN MARK

LOT No.

SOP24

Figure 3. Pin Configuration

Figure 4. Physical Dimension

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BD9421F

Electrical Characteristics(Unless otherwise specified VCC=24V Ta=25°C)

Limit

Parameter

[Whole Device]

Symbol

Unit

Condition

Min.

Typ.

Max.

－

Operation Current

ICC

IST

5

10

80

mA VSTB=3V

uA VSTB=0V

Standby Current

40

[UVLO Block]

Operation Voltage （VCC）

VUVLO_VCC

VUHYS_VCC

6.5

7.5

8.5

V

VCC=SWEEP UP

Hysteresis Voltage （VCC）

150

300

600

mV VCC=SWEEP DOWN

[DC/DC Block]

Error amp Base Voltage

Oscillation Frequency

VEAMP

FCT

0.55

142.5

90

0.60

150.0

95

0.65

157.5

99

V

BSx pin, VREF=0.9V

kHz RT=100kΩ

N Pin MAX DUTY Output

N Pin Source ON Resistance

N Pin Sink ON Resistance

RT Pin Voltage

NMAX_DUTY

RNSO

%

Ω

V

RT=100kΩ

2.5

2

5

10

RNSI

4

8

VRT

1.60

-0.3

-

2.00

-

2.40

VRTx90%

4.0

RT=100kΩ

RT Short Protection Range

RT Pin Low Resistance

RT_DET

RRT_L

V

RT=SWEEP DOWN

2.0

kΩ VSTB=0V

VBSx=0V, VREF=0.9V,

uA VFB=1.0V

VBSx=2.0V, VREF=0.9V,

uA VFB=1.0V

FB Pin Source Current

IFBSO

-115

-100

-85

FB Pin Sink Current

IFBSI

VCS

ICS

85

0.35

15

100

0.40

30

115

0.45

60

Over Current Detect Voltage

V

CS=SWEEP UP

CS Source Current

uA VCS=0V

[DC/DC Protection Block]

OVP High Detect Voltage

VOVPH

2.88

3.00

3.12

V

VOVP SWEEP UP

OVP Hysteresis Voltage

VOVPH_HYS

VSCP

150

200

250

V

VOVP SWEEP DOWN

Short Protection Detect Voltage

0.05

0.10

0.15

OVP Pin Leakage Current

OVP_LK

-2

0

2

uA VOVP=4V

[LED PNP Driver Block]

CL Pin Current Setting Voltage

(Analog MAX)

CL Pin Current Setting Voltage

(Analog MIN)

VCL

294.0

-3%

300.0

1.0

306.0

+3%

mV VREF=0.9V

VCLMAX

VCLMIN

V

VREF max=3.0V

-3%

200.0

mV VREF min=0.6V

PNP Driver Output Sink

Resistance

RBS

55

-2

80

0

120

2

Ω

PWM=High, VCL=Low

VREF Pin Leakage Current

VREF_LK

uA VREF=1V

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Electrical Characteristics(Unless otherwise specified VCC=24V Ta=25°C)

Limit

Parameter

Symbol

Unit

Condition

Min.

Typ.

Max.

[LED Protection Block]

LED OPEN Detect Voltage

LED SHORT Detect Voltage

VOPEN

VLSP

0.05

8.5

0.10

9.0

0.15

9.5

V

BSx=SWEEP DOWN

BSx=SWEEP UP

CL Pin Low Detect Voltage

VCLLVP

0.05

0.10

0.15

[REG75 Block]

REG75 Output Voltage

REG75

7.425

10

7.50

7.575

-

V

Io=0mA

REG75 MAX Output Current

| IREG75 |

－

mA

REG75_UVLO Detect Voltage

REG75_UVLO Hysteresis

REG75_TH

3.6

4.0

4.4

V

REG75=SWEEP DOWN

STB=ON->OFF,

REG75=SWEEP UP

STB=ON->OFF,

REG75=7.5V

REG75_HYS

250

500

750

mV

REG75 Discharge Resistance

REG75_DIS

0.65

1.00

1.35

MΩ

[STB Block]

STB Pin High Voltage

STB Pin Low Voltage

STBH

STBL

RSTB

2.0

-0.3

600

-

VCC

0.8

V

STB=SWEEP UP

STB=SWEEP DOWN

STB Pin Pull Down Resistance

1000

1400

kΩ STB=3.0V

[PWM Input Block]

PWM Pin High Detect Voltage

PWM Pin Low Detect Voltage

PWM Pin Pull Down Resistance

PWM_H

PWM_L

RPWM

1.5

-0.3

300

-

18

0.8

700

V

PWM=SWEEP UP

PWM=SWEEP DOWN

500

kΩ PWM=3.0V

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BD9421F

Pin Descriptions

Pin No.

Pin Name

REG75

N

Function

7.5V regulator output for N output pin

DC/DC switching output pin

1

2

3

PGND

CS

Power GND

4

DCDC external NMOS current monitor pin

DCDC phase-compensation pin

LED voltage setting pin

5

FB

6

VREF

BS1

BS2

BS3

BS4

BS5

BS6

CL6

7

PNP Tr Base connecting pin1

PNP Tr Base connecting pin2

PNP Tr Base connecting pin3

PNP Tr Base connecting pin4

PNP Tr Base connecting pin5

PNP Tr Base connecting pin6

PNP Tr collector ・current detection pin6

PNP Tr collector ・current detection pin5

PNP Tr collector ・current detection pin4

PNP Tr collector ・current detection pin3

PNP Tr collector ・current detection pin2

PNP Tr collector ・current detection pin1

Dimming signal input pin

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

CL5

CL4

CL3

CL2

CL1

PWM

OVP

RT

Overvoltage protection detection pin

DCDC frequency setting resistor connection pin

Analog GND

AGND

STB

VCC

Enable pin

Power supply pin

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Block Diagram

Vo

+

VIN

CIN

OVP

REF4V

OVP

UVLO

(VCC)

VCC

STB

REG75

Protection

TSD

OCP

VREG

OPEN

SHORT

Detect

CP counter

・・・

REG75

OSC CLK

Control Logic

N

RT

OSC

PGND

CS

ERROR

PGND

Soft Start

OSC CLK

SS counter

-

AGND

FB

-

ERR

AMP

RFB

CFB

VREF*2/3

1/10

+

Comp

+

SHORT_DET

REF4V

1/10

-

0.9V

-

OPEN_DET

-

Comp

REG75

+

0.1V

Analog

Dimming

VREF

1/3

PWM

Figure 5. Blockdiagram

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BD9421F

Pin ESD Type

REG75 / N / PGND / CS

PWM

FB

STB

VREF

BS(1-6) / CL(1-6)

OVP

RT

OVP

Figure 6. Pin ESD Type

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BD9421F

Description of pin function

P in 1: REG75

The REG pin is used in the DC/DC converter driver block to output 7.5V power. The maximum operating current is 10mA.

Using the REG pin at a current higher than 10mA can affect the N pin output pulse, causing the IC to malfunction and

leading to heat generation of the IC itself. To avoid this problem, it is recommended to make load setting to the minimum

level.

 Pin 2:N

The N pin is used to output power to the external NMOS gate driver for the DC/DC converter in the amplitude range of

approx. 0 to 7.5V. Frequency setting can be made with a resistor connected to the RT pin. For details of frequency

setting, refer to the description of the ＜RT pin＞.

 Pin 3: PGND

The PGND pin is a power ground pin for the driver block of the N output pin.

 Pin 4: CS

CS pin is current detect for DC/DC current mode inductor current control pin.

Current flowing through the inductor is converted into voltage by the current sensing resistor RCS connected to the CS

pin and this voltage is compared with voltage set with the error amplifier to control the DC/DC output voltage.

The CS pin also incorporates the overcurrent protection (OCP) function. If the CS pin voltage reaches 0.4V (Typ.) or

more, switching operation will be forcedly stopped.

 Pin 5: FB

Current mode control DC/DC converter error amplifier output pin. By monitoring voltage of BS（1～6）pin, the highest Vf of

LED column will set 2/3(typ.) of applied VREF voltage to BS pin voltage to control inductor current.

The phase compensation setting has described separately.

In addition, PWM pin will become High Impedance when all PWM signals are in low state, and will maintain FB voltage.

 Pin 6: VREF

LED current setting pin.1/3(typ) of applied voltage to VREF pin will be LED current

feedback voltage, 2/3(typ.) of its voltage will be DCDC feedback voltage（the

lowest BSx pin feedback voltage）.

Basically, because high accuracy of resistor divider is inputted to VREF pin

externally, the IC internally will be OPEN（High Impedance）state. Please use

external power to design it. It cannot be used in OPEN state.

 Pin 7-12: BS1-BS6

LED DRIVER output pin. Please connect to Base Terminal of external PNP Tr.

 Pin 13-18: CL6 – CL1

LED current detect pin. By monitoring voltage of CLx pin to detect LED current.

Please connect resistor to collector pin of external PNP Tr. CLx pin of no use channel set CLx>3.3V.

 Pin 19: PWM

ON/OFF terminal of LED driver pin. It inputs PWM dimming signal directly to adjust output DUTY dimming.

High/Low level of PWM terminal is shown as follows:

State

PWM Voltage

LED ON state

LED OFF state

PWM= 1.5V~18.0V

PWM= -0.3V～0.8V

 Pin 20: OVP

The OVP pin is an input pin for overvoltage protection and short circuit protection of DC/DC output voltage. When voltage

of it over 3.0V or higher, CP counting start.

When OVP pin voltage<0.1V (typ.) or lower, short circuit protection (SCP) function is activated, and output of Gate driver

will become low immediately.

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 Pin 21: RT

RT sets charge/discharge current determining frequency inside IC.

Only a resistor connected to RT determines saw-tooth wave frequency inside IC.

When RT=100kΩ,Frequency=150kHz(typ.).

For calculation example, please refer to section in “P15 – DC/DC drive frequency setting”.

When it reaches under VRT×0.90V(typ), DCDC operation will be stopped in order to prevent from high speed oscillation

when the RT resistance is shorted to GND. And when RT pin returns to normal state, DCDC also returns to operation.

 Pin 22: AGND

GND pin for analog system inside IC.

 Pin 23: STB

ON/OFF setting pin and allowed for use to reset the IC from shutdown.

※The IC state is switched (i.e., The IC is switched between ON and OFF state) according to voltages input in the STB

pin. Avoid using the STB pin between two states (0.8 to 2.0V).

 Pin 24: VCC

Power source pin of IC, which should be input in the range of 9 – 35 V.

Operation starts when VCC is 7.5V (TYP.) or higher and shuts down when VCC is 7.2 V (TYP.).

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BD9421F

Typical Performance Curves

10

9

8

7

6

5

4

3

2

1

0

10

9

8

7

6

5

4

3

2

1

0

9

13

17

21

VCC[V]

25

29

33

9

13

17

21

VCC[V]

25

29

33

Figure 7. Operating Current[mA] vs VCC Input Voltage[V]

Figure 8. REG75 Output Voltage[V] vs VCC Input Voltage[V]

2.0

10.00

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

1.00

0.10

0.01

15 35 55 75 95 115 135 155 175 195

0.6

1.1

1.6

2.1

2.6

RRT[k ]

VREF[V]

Ω

Figure 10. N Frequency[MHz] vs RT Resistance[kΩ]

Figure 9. CLx Voltage[V] vs VREF Input Voltage[V]

1.0

160

120

80

0.8

0.6

0.4

0.2

0.0

40

0

-40

-80

-120

-160

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

VBSx[V]

-40

-20

0

20

TEMP[

40

]

60

80

℃

Figure 12. FB Current[uA] vs BSx Voltage[V]

Figure 11. CLx Voltage[V] vs Temperature[℃]

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BD9421F

●LED current setting (VREF pin, CLx pin)

Please decide VREF pin input voltage first. When Analog dimming is performed,

please be noted that VREF pin input voltage range is (0.6V ～ 3.0V), and decide the

input voltage in normal operation. Basically, if VREF pin voltage is high, it will cause

power dissipation of external PNP Tr become high, so it is preferred to set the VREF pin

voltage lower.

Later, VREF=0.9V will be set as basic. For example if you create 0.9V from REG75, it

is possible to use resistive divider by setting 88kohm and 12kohm.

The LED current detection is performed by CLx pin. CLx pin is controlled so that the

voltage of 1/3V(typ.) of VREF voltage. If VREF=0.9V, CLx=0.3V to control external PNP

Tr. Therefore, if 「R_CL」 is set as a resistance which between CLx pin and GND, and

VREF pin voltage is set as 「V_VREF」, LED current 「I_LED」can be calculated as below.

V_VREF[V ]

R_CL[ohm] 

I

_LED[A]3

For current setting, set at each channel. For this reason, in 1ch～3ch and 4ch～6ch, it

is possible to change current by setting 「R_CL」value.

●DCDC operation frequency setting (RT Pin)

The operation frequency of DCDC output is set by resistance which connected to RT pin.

○The relationship between operation and RT resistance (ideal)

Here, fsw＝DCDC converter oscillation frequency[kHz]

15000

R_RT



[k]ꢀ

Above is ideal equations which do not putted with correction terms.

For accurate frequency setting, please confirm on the real system.

But the frequency setting range is 100kHz～800kHz.

f_SW[kHz]

【Setting Example】

If DCDC frequency is set to be 200kHz, RRT as below:

15000

R_RT



 75 [k] ꢀ

f_sw[kHz] 200[kHz]

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●Maximum DCDC output Voltage

In this IC, the voltage of BSx pin is depending on VREF pin voltage. The maximum voltage of VREF pin（VREF＝3.0V）,

the voltage of BSx pin will become 2.0V（2/3 of VREF voltage ）.

The maximum voltage of DCDC output will have been varying with 1.6V while Analog dimming is performed (2/3 of 3.0V -

0.6V).

●Soft Start Time setting

This IC have a built in soft start time setting, there is no need to change from the outside. Timer time can be set by

counting the clock frequency with RT pin. Starts counting when shutdown function terminal STB etc is released, and start

time are considered in the count (in soft-start). Therefore, LED OPEN protection ・SHORT protection are not detected

during this time.

The soft start time is set inside the IC, as the following equation.

(Please note that soft-start time set here is the mask of the running time and not the time until the output stabilizes of the

DCDC. Time to stabilize the output or load is greater than the boost DCDC dependent.)

Soft-start time "TSS", RT pin connection resistor "RRT" :

R_RT[]

T_SS[sec] 12480 

1.510¹⁰

Start-up sequence

The following describes the start-up sequence of this IC.

①

Internal SS

STB

SLOPE

FB

OSC

PWM

N

②

VOUT

③

ILED

④

LED_OK

⑥

⑤

○Description of start-up sequence

①Set STB from Low to High

②System will be activated while PWM=H. SS counting start.

At this time, a circuit in which internal SS voltage for slow start becomes equal to FB pin voltage operates to

equalize the FB pin and internal SS voltages regardless of whether the PWM pin is set to Low or High level.

③Since the FB pin and internal SS reach the lower limit of the internal sawtooth wave of the IC, the DC/DC converter

operates to start VOUT voltage rising.

④The Vout voltage continues rising to reach a voltage at which LED current starts flowing.

⑤When the LED current reaches the amount of current, isolate the FB circuit from the SS circuit. With this, the startup

operation is completed.

⑥After that, normal operation is controlled by following the feedback voltage of LED pins.

If the SS pin voltage reaches 4V or higher, the LED protection function will be activated to forcedly end the SS and FB

equalizing circuit.

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BD9421F

VOUT

●OVP/SCP setting procedure (OVP Pin)

The OVP pin is an input pin for overvoltage protection and short

circuit protection of DC/DC output voltage. The OVP pin is a high

impedance type and no pull-down resistor inside, resulting in

unstable potential in the open circuit state. To avoid this problem, be

sure to make input voltage setting with the use of a resistive divider.

R1

OVP

+

-

3.0V/2.8V

R2

○OVP detect setting equation

-

Assuming that voltage of VOUT rising abnormally and detecting

OVP is “VOVP_DET”, R1 and R2 setting will be made by the

following equation.

0.1V

+

○OVP release setting equation

When R1 and R2 setting is determined by the equation shown above, OVP release voltage VOVP_CANwill be given by the

following equation :

○SCP detect setting

The SCP setting「VSCP_DET」 voltage is calculated as below when R1,R2 is decided above:

(R1[k] R2[k])

VSCP  0.1V 

[V]

DET

R2[k]

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BD9421F

●Timer latch function

This IC has a built-in timer latch counter to make setting of timer latch time by counting a clock frequency set with the RT

pin.

○Timer latch time

The timer latch counter begins counting from the timing when any abnormal state is detected. The timer will be latched

after a lapse of a period of time given by the following equation.

If the abnormal state continues even when PWM is set to Low level, the counter will not reset counting.

Here LATCH_TIME= A period of time, which the timer is

latched

R_RT=RT pin connecting resistance

Protection time which described above is applied for LED OPEN protection, LED SHORT protection, SCP protection.

OVP protection as below:

Clock oscillation of timer latch uses DCDC clock. So timer latch time depend on unevenness of DCDC oscillation. In

150kHz, timer latch time is ±5% unevenness.

【Setting Example】

In LED_OPEN protection, LED_SHORT protection, SCP

protection,

When RT resistance=100kohm, the timer latch time is

And OVP protection is

Figure 13-1. Timing chart of LSP time latch

To prevent the miss detection there is 4 count interval of mask before starting the timer count at LED OPEN, SHORT and

GND SHORT protection.

If PWM=H time is

PWM=H time < 4count・・・Not detect protection because it is in interval time

PWM=H time > 4count・・・Detect protection because it is out of interval time

Please verify enough to operate narrow PWM.

Figure 13-2. Timing chart of Timer count

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BD9421F

●Selection of DC/DC Components

OCP setting / DCDC component current tolerance selection guide

The OCP detection function that is one of the functions of the CS pin will stop the DC/DC converter operating if the CS

pin voltage becomes larger than 0.4V.Consequently, it is needed to calculate a peak current flowing through the coil L and

then review the resistance of RCS. Furthermore, a current tolerance for DC/DC components should be larger than that for

peak current flowing through the coil L. The following describes the peak coil current calculation procedure, CS pin

connection resistor RCS selection procedure, and DC/DC component current tolerance selection procedure .

○Peak coil current Ipeak calculation

VOUT

Ripple voltage generated at the CS pin is determined by conditions

for DC/DC application components first, Assuming the conditions as

below:

L

VIN

IL

「output voltage=VOUT[V] 」

「LED total current=IOUT[A] 」

「DCDC input voltage=VIN[V] 」

「DCDC efficiency=η[%] 」

fsw

N

CS

And then mean input current IIN required for the whole system is given

by the following equation.

Rcs

V_OUT[V] I_OUT[A]

V_IN[V][%]

PGND

I_IN



[A]ꢀ

Further, according to drive operation with the DC/DC converter switching

frequency fsw [Hz], inductor ripple current ΔIL [A] generated at the inductor L (or

H) is given by the following equation.

(V_OUT[V ] V_IN[V ]) V_IN[V ]

L[H ]V_OUT[V ] f_SW[Hz]

ΔIL 

[A]

As a result, the peak current Ipeak of IL is given by the following equation.

IL[A]

Ipeak  I_IN[A]

[A](1)

2

○CS pin connection resistor RCS selection procedure

The current Ipeak flows into RCS to generate voltage.（See the timing

chart shown to the right）The voltage VCSpeak is given by the following

equation.

VCS _peak Rcs  Ipeak [V ]

If VCSpeak voltage reaches 0.4V, DC/DC output will stop. Consequently,

to select RCS resistance, the following condition should be met.

Rcs  Ipeak[V ]  0.4[V ]

○DC/DC component current tolerance selection procedure

Iocp current needed for OCP detection voltage CS to reach 0.4V is given

by the following equation:

0.4[V ]

I_OCP



[A](2)

Rcs[]

The relation among Ipeak current (Equation (1)), Iocp current (Equation (2)), and Maximum current tolerance for

component should meet the following equation.

I _peak I_OCP



MAX current tolerance

DC/DC application components including FETs, inductors, and diodes should be selected so that the Equation

shown above will be met.

In addition, it is recommended to use continuous mode in DCDC application. And the lower limit value of coil ripples

current Imin so as to meet the following equation:

IL[A]

I min  I _IN[A] 

[A]  0

2

A failure to meet this condition is referred to as discontinuous mode and this failure may result in an inadequate rise in

output voltage.

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【Setting example】

Output=VOUT[V]=40V

LED 1ch current=120mA, total LED current IOUT[A]=120mA×6ch=0.72A

DCDC input voltage=VIN [V] =24V

DCDC efficiency=η[%]=90%

Mean input current IIN required for the whole system is given by the following equation:

DCDC switching frequency=fsw[Hz]=200kHz

Inductor [H]=33μH

The inductor ripple current ΔIL [A] is given by the following equation:

(V_OUT[V ] V_IN[V ]) V_IN[V ]

L[H ]V_OUT[V ] f_SW[Hz]

(40[V ]  24[V ])  24[V ]

3310^6[H ] 40[V ] 200 10³[Hz]

ΔIL 

ꢀ

 1.45 [A]

As a result, the peak current Ipeak of IL is given by the following equation.

When RCS resistance is set to 0.1ohm, the VCS peak voltage will be given by the following equation:

Consequently, the result meets the condition.

Furthermore, I_OCPcurrent at which OCP is detected is given by the following equation:

0.4[V ]

I_OCP



 4.0 [A]

0.1[]

So must select the component of about 5A in order to meet the above result.

Max. Current tolerance for component

I _peak I_OCP



Particularly, To select DC/DC components, give consideration to IC variations as well as individual component

variations, and then conduct thorough verification on practical systems..

The lower limit value of coil ripple current Imin is given by the following equation, the component will not be put into

discontinuous mode.

IL[A]

I min I_IN[A]

[A] 1.33[A] 0.73[A] 0.60[A] 0

2

※For the selection of DC/DC components, please also consider the inaccuracy of each componentts.

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○Selection of inductor L

The value of inductor has significant influence on the input ripple current. As

shown by Equation (1), the larger the inductor and the higher the switching

frequency, the inductor ripple current ∆IL becomes increasingly lower.

ΔIL

(V_OUT V_IN) V_IN

L V_OUT f_SW

ΔIL 

[ꢀA]ꢀꢀꢀꢀ・・・・・ꢀꢀ(1)

V

IN

Expressing efficiency as shown by Equation (2), peak input current is given as

Equation (3).

I_L

L

V_OUT I_OUT

V_IN I_IN

 

ꢀꢀꢀꢀꢀ・・・・・ꢀꢀ(2)

V_OUT

V_OUT I_OUT

V_IN

ΔIL

IL_MAX I_IN





ꢀꢀ ꢀꢀ ꢀ・・・・・ꢀ(ꢀ3)

2

Here,

L：Inductor value[H]

V_IN：input voltage[V]

I_IN：input current[A]

V

_OUT：DC/DC output voltage[V]

I

_OUT：output total current[A]

R

F_SW：Oscillation frequency[Hz]

CS

C_OUT

Basically, make setting of ∆IL to approximately 30% to 50% of the output load

current.

※

If a current in excess of the rated current of the inductor applies to the coil, the inductor will cause magnetic

saturation, resulting in efficiency degradation.

Select an inductor with an adequate margin so that peak current will not exceed the rated current of the inductor.

※

To reduce power dissipation from and increase efficiency of inductor, select an inductor with low resistance

component (DCR or ACR).

○Selection of output capacitor C_OUT

Select a capacitor on the output side taking into account the stability region

of output voltage and equivalent series resistance necessary to smooth

ripple voltage. Note that higher output ripple voltage may result in a drop in

LED pin voltage, making it impossible to supply set LED current.

The output ripple voltage ∆V_OUTis given by Equation (4).

V

IN

I_L

I_OUT

1

L

ΔV_OUT ILMAX  R_ESR





[ꢀV]ꢀ・・・・・ꢀꢀ(4)

C_OUT



f_SW

V_OUT

Here, R_ESR Equivalent series resistance of C_OUT

.

R

ESR

R

CS

C_OUT

※

Select capacitor ratings with an adequate margin for output voltage.

To use an electrolytic capacitor, an adequate margin should be provided for permissible current. Particularly to

apply PWM light modulation to LED, note that a current higher than the set LED current transiently flows.

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○Selection of switching MOSFET transistors

There will be no problem for switching MOSFET transistors having absolute maximum rating higher than rated current

of the inductor L and VF higher than “C_OUTbreakdown voltage  Rectifier diode”. However, to achieve high-speed

switching, select transistors with small gate capacity (injected charge amount).

Note: Rated current larger than overcurrent protection setting current is recommended.

Note: Selecting transistors with low on resistance can obtain high efficiency.

○Selection of rectifier diodes

Select Schottky barrier diodes having current capability higher than the rated current of the inductor L and inverse

breakdown voltage higher that C_OUTbreakdown voltage, particularly having low forward voltage VF.

○Selection of Load switch MOSFET and soft start function

In usual DC/DC converter, because there is no switching to a path leading from V_INto V_OUTresulting in output voltage

is also occurring even if IC is in OFF state. Please insert PMOSFET between V_INand inductor if you want voltage to 0V

until the IC starts to operate. In addition, FAIL pin can be used for driving load switch after confirmed the logic theory,

and the breakdown voltage of drain-source needed to be selected larger than V_IN.

Furthermore, if you would like to make soft start function to load switch, please insert a condenser between Gate

and Source.

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BD9421F

●Phase Compensation Setting Procedure

DC/DC converter application for current mode control includes one each of pole f_p(phase delay) by CR filer consisting

of output capacitor and output resistor (i.e., LED current) and zero (phase lead) f_Zby the output capacitor and capacitor

ESR.

Furthermore, the step-up DC/DC converter includes RHP zero “f_ZRHP” as the second zero. Since the RHP zero has

phase delay (90) characteristics like the pole, the crossover frequency f_cshould be set to not more than RHP zero.

VIN

VOUT

L

ILED

VOUT

-

+

FB

gm

RESR

COUT

RFB1

CFB2

RCS

CFB1

i.

Find Pole f_pand RHP zero f_ZRHPof DC/DC converter.

V_OUT (1 D)²

2  L I_LED

I_LED

f_p

ꢀ[Hz] ꢀ

f_ZRHP



[ꢀHz]ꢀꢀ

2 V_OUTC_OUT

I_LEDꢀ^{＝LED Total current[A],}

Here,

V_OUTV_IN

D 

ꢀ

V_OUT

ii.

Find phase compensation to be inserted to error amplifier.(set f_cis 1/5 to f_ZRHP)

1

f_RHZP R_CS I_LED

C_FB1



[ꢀF]ꢀꢀ

R_FB1



[ꢀ] ꢀ

2  R_FB1 f _p

5 f _p gmV_OUT (1 D)

gm  4.010^4[S]

Here,

iii.

Find zero used to compensate ESR (R_ESR) of C_OUT(electrolytic capacitor).

R_ESRC_OUT

C_FB2



[ꢀF]ꢀꢀ

R_FB1

※Even if a ceramic capacitor (R_ESRof the order of milliohms) for C_OUT, it is recommended to insert C_FB2for

stable operation.

To improve transient response, it is necessary to increase R_FB1and reduce C_FB1. However, this improvement reduces

a phase margin. To avoid this problem, conduct thorough verification, including variations in external components, on

practical systems.

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BD9421F

●The setting of REG75 capacity and shutdown procedure

VOUT discharge function is built-in this IC when IC is shutdowned, the below decribes the operation sequence.

Figure 14.Timing chart of shutdown

○Explanation of shutdown sequence

①Set STB pin to “OFF” will stops DC/DC converter and REG75, but LED driver will remain operation.

②Discharge the REG75 pin voltage from 7.5V to 4.0V with 1MΩ.

③The VOUT voltage will be discharged with ILED current and the discharged VOUT voltage is no flow ILED current.

④When REG75 pin voltage will reach 4.0V (Typ.) or less to shut down all systems

○REG75 capacitance setting procedure

The shutdown time “T_OFF” can be calaulated by the following equation.

REG75 [V]

7.5[V]

4.0[V]

3

t0

T [sec]  C [F] R [] In

 C [F]1[M] In

 628.6 10  C [sec]

OFF

REG

REG75 [V]

UVLO

The longest VOUT discharge time will be obtained when the PWM duty cycle is set to the minimum VOUT.

Make REG capacitance setting with an adequate margin so that systems will be shut off after VOUT voltage is fully

discharged.

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BD9421F

●Timing Chart

7.5V

VCC

STB

2.0V

0.8V

PWM

4.5V

REG75

RT

2.0V

4.0V

Internal SS

FB

VOUT

Protect Function

disable

LED OPEN

LED SHORT

OVP

disable

*Under SS term, Not charge CP

disable

SCP

OCP

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BD9421F

●List of Protection Functions

○List of protection detecting condition

Detection

Protection

Detection condition

PWM

Release

condition

Protection

type

Timer

Detection pin

condition

names

SS

H(Pulse

over 4CLK)

H(Pulse

over 4CLK)

H(Pulse

over 4CLK)

H(Pulse

over 4CLK)

BSx

BSx < 0.1V

CLx < 0.1V

BSx > 9V

SS>4.0V

BSx > 0.1V

CLx > 0.1V

BSx < 9V

Latch(Only

detected ch)

LED OPEN

2¹⁵count

CLx

SS>4.0V

Latch(Only

detected ch)

LED SHORT

BSx

SS>4.0V

LED GND

SHORT

RT GND

SHORT

2¹⁵+2⁷coun

t

BSx

BSx < 0.1V

SS>4.0V

BSx > 0.1V

Latch

Under RT

x90%

Canceled

RT=GND State

Immediatel

y detect

Immediatel

y detect

Immediatel

y detect

RT

-

Auto-restart

VCC UVLO

VCC

REG75

VCC < 7.2V

VCC>7.5V

REG75

UVLO

REG75 < 4.0V

REG75>4.5V

OVP

SCP

OVP

OVP>3.0V

-

OVP<2.8V

2¹⁸count

2¹⁵count

Latch

OVP < 0.1V

OVP > 0.1V

Immediatel

y detect

OCP

CS

CS>0.4V

-

CS<0.4V

Pulse by Pulse

・To clear the latch type, STB should be set to “L” once, and then to “H”.

・The count of Timer means “1count=1duty of switching frequency.”

○List of protection detecting operation

Operation when the hysteresis type protection is detected

Protection

Functions

DC/DC

LED Driver

Soft start

RT pin

Stops operating

Only detected LED stops

Low after all ch

Latch

Low after all ch

Latch

LED OPEN

after CP counting operating after CP counting

Stops operating Only detected LED stops

after CP counting operating after CP counting

Low after all ch

Latch

Low after all ch

Latch

LED SHORT

LED GND

SHORT

RT GND

SHORT

Stops operating

after CP counting

Instantaneously

stops operating

Instantaneously

stops operating

Instantaneously

stops operating

Instantaneously

stops operating

Stops operating after CP

counting

Discharge after

CP counting

Low after CP

counting

Instantaneously stops

operating

Not discharged

Discharge

-

Instantaneously stops

operating

VCC UVLO

REG75 UVLO

OVP

Normal operation

Instantaneously stops

operating

Discharge

Stops operating after CP

counting

Discharge after

CP counting

Low after CP

counting

Stops operating after CP

counting

Discharge after

CP counting

Low after CP

counting

SCP

OCP

N output stops

Limits duty cycle

Normal operation

Not discharged

Normal operation

Case FOSC=150kHz

○LED OPEN,LED SHORT,SCP

32768count→Latch after 218.5msec

○LED GND SHORT

32896count→Latch after 219.3msec

○OVP

262144count→Latch after 1.748sec

○Soft Start time

12480count→83.2msec

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BD9421F

○Timing of Error detection

This IC is individual Latch OFF. Therefore, Error detection is every channel.

The detection timing of LED OPEN, SHORT and GND SHORT Protection is different with PWM Duty or Timing of Error state as

follows:

(A).Other channels will be in Error states within 4counts of internal CLK. [When PWM=100%]

※Error detection is same timing.

(B).Other channels will be in Error states after 4counts of internal CLK. [When PWM=100%]

PWM

H

0.3V

CL1_Voltage

CL2_Voltage

0V

0.3V

0V

Oscllator

(Internal IC)

4CLK

CH1_Error_Detect

(Internal IC)

Error detect

CH2_Error_Detect

(Internal IC)

Error no detect

L

※Error detection is only first Error state channel.

(C).Other channels will be in Error states after 4counts of internal CLK. [When except PWM=100%]

※First Error state channel is Latch OFF. Then, the detection of the following channel can detect whenever the new edge

of PWM comes. Finally, all Error state channels are Latch off.

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BD9421F

Operational Notes

1.

Reverse Connection of Power Supply

Connecting the power supply in reverse polarity can damage the IC. Take precautions against reverse polarity when

connecting the power supply, such as mounting an external diode between the power supply and the IC’s power supply

terminals.

2. Power Supply Lines

Design the PCB layout pattern to provide low impedance supply lines. Separate the ground and supply lines of the

digital and analog blocks to prevent noise in the ground and supply lines of the digital block from affecting the analog

block. Furthermore, connect a capacitor to ground at all power supply pins. Consider the effect of temperature and

aging on the capacitance value when using electrolytic capacitors.

3.

4.

Ground Voltage

Ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition.

Ground Wiring Pattern

When using both small-signal and large-current ground traces, the two ground traces should be routed separately but

connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signal

ground caused by large currents. Also ensure that the ground traces of external components do not cause variations on

the ground voltage. The ground lines must be as short and thick as possible to reduce line impedance.

5.

Thermal Consideration

Should by any chance the power dissipation rating be exceeded the rise in temperature of the chip may result in

deterioration of the properties of the chip. The absolute maximum rating of the Pd stated in this specification is when the

IC is mounted on a 70mm x 70mm x 1.6mm glass epoxy board. In case of exceeding this absolute maximum rating,

increase the board size and copper area to prevent exceeding the Pd rating.

6.

7.

Recommended Operating Conditions

These conditions represent a range within which the expected characteristics of the IC can be approximately obtained.

The electrical characteristics are guaranteed under the conditions of each parameter.

Inrush Current

When power is first supplied to the IC, it is possible that the internal logic may be unstable and inrush current may flow

instantaneously due to the internal powering sequence and delays, especially if the IC has more than one power supply.

Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of

connections.

8.

9.

Testing on Application Boards

When testing the IC on an application board, connecting a capacitor directly to a low-impedance output pin may subject

the IC to stress. Always discharge capacitors completely after each process or step. The IC’s power supply should

always be turned off completely before connecting or removing it from the test setup during the inspection process. To

prevent damage from static discharge, ground the IC during assembly and use similar precautions during transport and

storage.

Inter-pin Short and Mounting Errors

Ensure that the direction and position are correct when mounting the IC on the PCB. Incorrect mounting may result in

damaging the IC. Avoid nearby pins being shorted to each other especially to ground, power supply and output pin.

Inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment) and

unintentional solder bridge deposited in between pins during assembly to name a few.

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BD9421F

Operational Notes – continued

10. Unused Input Terminals

Input terminals of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance

and extremely low capacitance. If left unconnected, the electric field from the outside can easily charge it. The small

charge acquired in this way is enough to produce a significant effect on the conduction through the transistor and

cause unexpected operation of the IC. So unless otherwise specified, unused input terminals should be connected to

the power supply or ground line.

11. Regarding the Input Pin of the IC

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 the P layers with the N layers of other elements, creating a

parasitic diode or transistor. For example (refer to figure below):

When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode.

When GND > Pin B, 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, operational faults, or physical damage. Therefore, conditions that cause these diodes to

operate, such as applying a voltage lower than the GND voltage to an input pin (and thus to the P substrate) should

be avoided.

Figure 15. Example of monolithic IC structure

12. Ceramic Capacitor

When using a ceramic capacitor, determine the dielectric constant considering the change of capacitance with

temperature and the decrease in nominal capacitance due to DC bias and others.

13. Area of Safe Operation (ASO)

Operate the IC such that the output voltage, output current, and power dissipation are all within the Area of Safe

Operation (ASO).

14. Thermal Shutdown Circuit(TSD)

This IC has a built-in thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always be

within the IC’s power dissipation rating. If however the rating is exceeded for a continued period, the junction

temperature (Tj) will rise which will activate the TSD circuit that will turn OFF all output pins. When the Tj falls below the

TSD threshold, the circuits are automatically restored to normal operation.

Note that the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no

circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC from heat

damage.

15. Over Current Protection Circuit (OCP)

This IC incorporates an integrated overcurrent protection circuit that is activated when the load is shorted. This

protection circuit is effective in preventing damage due to sudden and unexpected incidents. However, the IC should

not be used in applications characterized by continuous operation or transitioning of the protection circuit.

Status of this document

The Japanese version of this document is formal specification. A customer may use this translation version only for a

reference to help reading the formal version.

If there are any differences in translation version of this document formal version takes priority

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BD9421F

Ordering Information

B D 9

4

2

1

F

-

XX

Part Number

Package

F:SOP24

Packaging and forming specification

XX: Please confirm the formal name

to our sales.

Physical Dimension, Tape and Reel Information

SOP24

15.0 0.2

Tape

Embossed carrier tape

2000pcs

(MAX 15.35 include BURR)

Quantity

24

13

E2

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

(

)

1

12

0.15 0.1

1.27

0.4 0.1

0.1

Direction of feed

1pin

Reel

Order quantity needs to be multiple of the minimum quantity.

(Unit : mm)

∗

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BD9421F

Revision History

Date

Revision

001

Changes

11.Nov.2013

New Release

P14. Timing chart of Timer count add

P22. Detection condition add

P23. Timing of Error detection add

P2. External Component Recommended Range add

P8. No use channel setting add

31.Jan.2014

25.Sep.2015

002

003

P22. Protection condition change

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Notice

Precaution on using ROHM Products

1. Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment,

OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you

intend to use our Products in devices requiring extremely high reliability (such as medical equipment ^{(Note 1)}, transport

equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car

accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or

serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance.

Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any

damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific

Applications.

(Note1) Medical Equipment Classification of the Specific Applications

JAPAN

USA

EU

CHINA

CLASSⅢ

CLASSⅣ

CLASSⅡb

CLASSⅢ

2. ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor

products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate

safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which

a failure or malfunction of our Products may cause. The following are examples of safety measures:

[a] Installation of protection circuits or other protective devices to improve system safety

[b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure

3. Our Products are designed and manufactured for use under standard conditions and not under any special or

extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way

responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any

special or extraordinary environments or conditions. If you intend to use our Products under any special or

extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of

product performance, reliability, etc, prior to use, must be necessary:

[a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents

[b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust

[c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2,

H2S, NH3, SO2, and NO2

[d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves

[e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items

[f] Sealing or coating our Products with resin or other coating materials

[g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of

flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning

residue after soldering

[h] Use of the Products in places subject to dew condensation

4. The Products are not subject to radiation-proof design.

5. Please verify and confirm characteristics of the final or mounted products in using the Products.

6. In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied,

confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power

exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect

product performance and reliability.

7. De-rate Power Dissipation (Pd) depending on Ambient temperature (Ta). When used in sealed area, confirm the actual

ambient temperature.

8. Confirm that operation temperature is within the specified range described in the product specification.

9. ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in

this document.

Precaution for Mounting / Circuit board design

1. When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product

performance and reliability.

2. In principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must

be used on a through hole mount products. If the flow soldering method is preferred on a surface-mount products,

please consult with the ROHM representative in advance.

For details, please refer to ROHM Mounting specification

Notice-PGA-E

Rev.001

Daattaasshheeeett

Precautions Regarding Application Examples and External Circuits

1. If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the

characteristics of the Products and external components, including transient characteristics, as well as static

characteristics.

2. You agree that application notes, reference designs, and associated data and information contained in this document

are presented only as guidance for Products use. Therefore, in case you use such information, you are solely

responsible for it and you must exercise your own independent verification and judgment in the use of such information

contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses

incurred by you or third parties arising from the use of such information.

Precaution for Electrostatic

This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper

caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be

applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron,

isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).

Precaution for Storage / Transportation

1. Product performance and soldered connections may deteriorate if the Products are stored in the places where:

[a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2

[b] the temperature or humidity exceeds those recommended by ROHM

[c] the Products are exposed to direct sunshine or condensation

[d] the Products are exposed to high Electrostatic

2. Even under ROHM recommended storage condition, solderability of products out of recommended storage time period

may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is

exceeding the recommended storage time period.

3. Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads

may occur due to excessive stress applied when dropping of a carton.

4. Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of

which storage time is exceeding the recommended storage time period.

Precaution for Product Label

QR code printed on ROHM Products label is for ROHM’s internal use only.

Precaution for Disposition

When disposing Products please dispose them properly using an authorized industry waste company.

Precaution for Foreign Exchange and Foreign Trade act

Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign

trade act, please consult with ROHM in case of export.

Precaution Regarding Intellectual Property Rights

1. All information and data including but not limited to application example contained in this document is for reference

only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any

other rights of any third party regarding such information or data.

2. ROHM shall not have any obligations where the claims, actions or demands arising from the combination of the

Products with other articles such as components, circuits, systems or external equipment (including software).

3. No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any

third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM

will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to

manufacture or sell products containing the Products, subject to the terms and conditions herein.

Other Precaution

1. This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM.

2. The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written

consent of ROHM.

3. In no event shall you use in any way whatsoever the Products and the related technical information contained in the

Products or this document for any military purposes, including but not limited to, the development of mass-destruction

weapons.

4. The proper names of companies or products described in this document are trademarks or registered trademarks of

ROHM, its affiliated companies or third parties.

Notice-PGA-E

Rev.001

Daattaasshheeeett

General Precaution

1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents.

ROHM shall not be in an y way responsible or liable for failure, malfunction or accident arising from the use of a ny

ROHM’s Products against warning, caution or note contained in this document.

2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior

notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s

representative.

3. The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all

information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or

liable for any damages, expenses or losses incurred by you or third parties resulting from inaccuracy or errors of or

concerning such information.

Notice – WE

Rev.001

Datasheet

Buy

BD9421F - Web Page

Distribution Inventory

Part Number

Package

Unit Quantity

BD9421F

SOP24

2000

Minimum Package Quantity

Packing Type

Constitution Materials List

RoHS

2000

Taping

inquiry

Yes


型号：	BD9421F_15
厂家：	ROHM
描述：	White LED Driver for large LCD Panels (DCDC Converter Type) CD
文件：	总31页 (文件大小：1174K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

BD9421F_15 [ROHM]

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