AN37000A - Panasonic - Datasheet.Live

Publication date: November 2010 Ver. AEB

DATA SHEET

Part No.

Package Code No.

AN37000A

HSOP056-P-0300B

AN37000A

Ver. AEB

Contents

Overview …………………………………………………………………………………………………………….. 3

Features …………………………………………………………………………………………………………….. 3

Applications ………………………………………………….……………………………………………………… 3

Package ………………………………………………….…………………………………………………………. 3

Type ……………………………………………………….…………………………………………………………. 3

Application Circuit Example (Block Diagram) …………………………………………………………………… 4

Pin Descriptions ………………………………………….………………………………………………………… 5

Absolute Maximum Ratings ……………………………….……………………………………………………… 7

Operating Supply Voltage Range …………………….…………………………………………………………… 7

Recommended use conditions …………………………………………………………………………………… 7

Allowable Current and Voltage Range …………………………………………………………………………… 8

Electrical Characteristics …………….…………………………………………………………………………… 9

Technical Data ………………………………………….…………………………………………………………… 14

yPD⎯Tadiagram ……………………………………………………………………………………………….. 14

Usage Notes ………………………………………….……………………………………………………………. 15

ySpecial attention and precaution in using ………………………………………………………………………. 15

yNotes of Power LSI ………………………………………………………………………………………………. 16

AN37000A

Ver. AEB

AN37000A

8-channel LED driver for LCD TV backlight

Built-in step-up DC/DC converter

Overview

AN37000A is a 8-channel LED driver IC for LCD TV backlight. It has a built-in high efficiency DC/DC converter.

The current of each channel is controlled by 12-bit PWM data from serial I/F.

The peak value of LED current is set by an external resistor or 8-bit DAC. The current capability of each channel is 85 mA.

Features

yLED driver IC with 8-channel constant current output

yLED drive current capability of each channel : 85 mA

yAll the constant current of each channel can be set by one external resistor. (Pin ISET)

yBuilt-in 8-bit DAC which can set the constant current of all channels

yIt is possible to control 12-bit PWM duty by serial I/F.

yIt is possible to drive 9-serise LEDs per one channel by an built-in DC/DC converter (up to 35 V) (depend on the VF value of LED)

yBuilt-in various protection functions

xThermal shutdown protection

xOver-voltage protection

xOver-current protection

xLED abnormal detection

xUnder-voltage lock-out protection for power supply pin etc.

yBuilt-in 5 V regulator for internal circuits of IC

yThe switching frequency of DC/DC converter is synchronized with an external signal (Pin TEXCLK)

Applications

yLED backlight for LCD TV, LCD monitor

Package

y56 pin Plastic Small Outline Package With Heat Sink (SOP Type)

Type

yBi–CDMOS IC

AN37000A

Ver. AEB

Application Circuit Example (Block Diagram)

DATAIN

ENABLE

READ

ISET

CTL

DATAOUT

TEXCLK

OVP

GND2

FLAG

LOGIC

BLOCK

FB0 FB1 FB2 FB3 FB4 FB5 FB6 FB7

GND4(2)

STBY

TSD

OSC VREGIN

GND3

STBY

SPRT

SOFT

PRE-

DRV

SW_OFF

SW_ON

GND4(1)

SCLK

DIMCLK

GND4(4)

GND4(3)

VCNT

(Reference CLK

for setting Duty)

4256 55 53

552

GND1(1)

CURRENT

SOURCE

AMP

CTWLX VIN

11 V

(5 V)

10 μH

120 pF

5.1 kΩ

100 kΩ

1μF

3.0 k Ω

0.47 μF

Ceramic

capacitor

1 μF

0.0082 μF

VREG

CH3 CH4 CH6

LOG

VREG

BGR

FAULT DETECTION,

OVP, UVLO, LED_DET,

CUR_LIM, TSD TIMER

LATCH

VREG

AMP

VREG

220 μF

FAULT

UVLOOFF

DRS

100 Ω

DAC

(OPEN setting)

Serial control

GND1(2)

CGND1

CGND2

25 26 27 28 29 30 31 32 33

CH5 CH7CH0 CH1 CH2

COMP

Notes) yThis application circuit is an example. The operation of mass production set is not guaranteed. Perform enough evaluation and verification

on the design of mass production set.

yThis block diagram is for explaining functions. Part of the block diagram may be omitted, or it may be simplified.

yUse a resistor with high accuracy as an external resistor of Pin 46 (ISET) in order to set FB pin current to high accuracy.

yIn the case of the set which does not use SW_ON, SW_OFF pin, set these pins as the above-mentioned figure.

AN37000A

Ver. AEB

LED forced ON input (At SW_OFF = High, High : Forced ON)InputSW_ON22

LED forced OFF input (Low : forced OFF)InputSW_OFF23

N.C.—N.C.20

N.C.—N.C.21

Power GND only for FB pinGroundGND4(1)18

Power GND only for FB pinGroundGND4(2)19

COM GND1—CGND115

Reference clock signal input for setting duty of driving LEDInputDIMCLK11

N.C.—N.C.35

N.C.—N.C.34

N.C.—N.C.33

LED cathode drive output 4OutputFB429

LED cathode drive output 5OutputFB530

LED cathode drive output 6OutputFB631

LED cathode drive output 7OutputFB732

LED cathode drive output 2OutputFB227

LED cathode drive output 3OutputFB328

LED cathode drive output 1OutputFB126

LED cathode drive output 0OutputFB025

N.C.—N.C.24

Serial setting mode switching (Low : Duty setting, High : DAC and the others setting)InputDRS17

Latch signal inputInputCTL16

Serial data signal inputInputDATAIN14

Serial clock signal inputInputSCLK13

Enable signal inputInputENABLE12

Internal serial data read mode switching (High : Read)

InputREAD10

Input pin to prohibit VIN under-voltage protection (High : Prohibition)InputUVLOOFF9

Power GND for LX pinGroundGND38

N.C.—N.C.7

Inductor driveOutputLX6

N.C.—N.C.5

External PMOS gate controlOutputFAULT4

Power supply inputPower supplyVIN3

N.C.—N.C.2

DC/DC output voltage detectionInputOVP1

DescriptionTypePin namePin No.

Pin Descriptions

AN37000A

Ver. AEB

Abnormal condition detection output (High : Normal, Low : Abnormal)

Note) Open-drain

OutputFLAG53

Triangular wave generation for setting DC/DC switching frequency (External : 120 pF)—CTW54

External synchronous input for setting DC/DC switching frequencyInputTEXCLK55

Standby switching input (High : Normal operation, Low : Standby)InputSTBY56

N.C.—N.C.52

Power supply input for logic (Connect with VREG pin externally.)InputVREGIN50

External capacitor connection pin for internal stabilized power supply (5 V)

(Ceramic capacitor : 1 μF)

OutputVREG51

N.C.—N.C.49

GND for setting LED currentGroundGND247

Main GNDGroundGND1(1)48

Error amp. reference voltage output (default : OPEN)OutputVCNT45

External resistor connection pin for setting LED current—ISET46

External capacitor connection pin for timer of protection function—SPRT44

External component connection pin for DC/DC phase compensation—EO43

COM GND2—CGND242

Serial data outputOutputDATAOUT40

Power GND only for FB pinGroundGND4(3)38

Power GND only for FB pinGroundGND4(4)39

GNDGroundGND1(2)37

N.C.—N.C.36

External capacitor connection pin for soft start—

SOFT41

DescriptionTypePin namePin No.

Pin Descriptions (continued)

AN37000A

Ver. AEB

°C

–55 to +150Tstg

Storage temperature5

*3mA160IFB0ABS to IFB7ABS

FB pin current6

－℃

+150Tj

Junction temperature7

—A—IVINSupply current2

NotesUnitRatingSymbolParameterA No.

°C

–40 to +85Topr

Operating ambient temperature4

*2mW457PD

Power dissipation3

*1V38VINSupply voltage1

Recommended Use Conditions

—VVIN to 35VOVP

OVP pin voltage (DC/DC output)

—mA10 to 85IFB0 to IFB7

FB pin current 1 (duty ≤100%)

—MHz

≤10

fSCLK

SCLK pin frequency

—V0.4 to 2VFB0 to VFB7

FB pin voltage (FB pin current : ON)

—mA10 to 120

IFB0MAX to IFB7MAX

FB pin current 2 (duty ≤50%)

—MHz

≤10

fDIMCLK

DIMCLK pin frequency

NotesUnitRangeSymbolParameter

*1*2V10 to 34VINSupply voltage range

NotesUnitRangeSymbolParameter

Absolute Maximum Ratings

Note) Absolute maximum ratings are limit values which do not result in damages to this IC, and IC operation is not guaranteed at these limit values.

Notes) *1 : The values under the condition not exceeding the above absolute maximum ratings and the power dissipation.

*2 : The power dissipation shown is the value at Ta=85°C for the independent (unmounted) IC package without a heat sink.

When using this IC, refer to •PD-Tadiagram in the Technical Data standard and design the heat radiation with sufficient margin so that the

allowable value might not be exceeded based on the conditions of power supply voltage, load, and ambient temperature.

*3 : Except for the power dissipation, operating ambient temperature, and storage temperature, all ratings are for Ta=25°C.

*4 : Refer to Allowable Current and Voltage Range for the allowable voltage and current of each pin.

Operating Supply Voltage Range

Notes) *1 : The values under the condition not exceeding the above absolute maximum ratings and the power dissipation.

*2 : When UVLOOFF (Pin 9) is set to High, this IC can be used in the range of 8.3 V ≤VIN ≤34 V (Ta≥25°C ). However, since UVLO_VIN

function is OFF, be sure to obey Usage Notes shown in No.14.

AN37000A

Ver. AEB

*1, 2V

−0.3 to VREG

DATAOUT40

*1, 2V

−0.3 to VREG

SOFT41

*1V

−0.3 to VREG

VCNT45

*1, 2V

−0.3 to VREG

ISET46

*1, 3V

−0.3 to VREG

VREGIN50

*2V

−0.3 to 6

VREG51

*1, 2V

−0.3 to VREG

FLAG53

*1, 2V

−0.3 to VREG

CTW54

*1V

−0.3 to VREG

TEXCLK55

*1V

−0.3 to VREG

STBY56

—

−0.3 to 38

FB530

—

−0.3 to 38

FB631

—

−0.3 to 38

FB732

—

−0.3 to 38

FB429

—

−0.3 to 38

FB328

*2V

−0.3 to 38

FAULT4

*1V

−0.3 to VREG

SW_ON22

*1V

−0.3 to VREG

SW_OFF23

—

−0.3 to 38

FB025

—

−0.3 to 38

FB126

—

−0.3 to 38

FB227

*1V

−0.3 to VREG

ENABLE12

*1V

−0.3 to VREG

SCLK13

*1V

−0.3 to 5.5

DATAIN14

*1V

−0.3 to VREG

CTL16

*1V

−0.3 to VREG

DRS17

*1V

−0.3 to VREG

DIMCLK11

*1V

−0.3 to VREG

*1V

−0.3 to VREG

UVLOOFF9

*2V

−0.3 to 50

LX6

−0.3 to 50

OVP

Notes

UnitRatingPin namePin No.

—

Notes) *1 : VREG must not be exceeded 6 V.

*2 : Do not apply external voltages.

The pin voltage must not exceed the rated value transiently.

*3 : Be sure to connect with VREG pin externally.

—

mA0 to 160FB732

—

mA0 to 160FB025

—

mA0 to 160FB126

—

mA0 to 160FB227

—

mA0 to 160FB328

—

mA0 to 160FB429

—

mA0 to 160FB530

—

mA0 to 160FB631

—

−1 to 1

DATAOUT40

—

A0 to 3LX6

Notes

UnitRatingPin namePin No.

Notes) yAllowable current and voltage ranges are limit ranges which do not result in damages to this IC, and IC operation is not guaranteed within

these limit ranges.

yVoltage values, unless otherwise specified, are with respect to GND.

GND is voltage for GND1(1), GND1(2), GND2, GND3, GND4(1), GND4(2), GND4(3),GND4(4), CGND1 and CGND2.

GND1(1) = GND1(2) = GND2 = GND3 = GND4(1) = GND4(2) = GND4(3) = GND4(4) = CGND1 = CGND2.

yDo not apply external currents or voltages to any pin not specifically mentioned.

yFor the circuit currents, "+" denotes current flowing into the IC, and "−" denotes current flowing out of the IC.

Allowable Current and Voltage Range

AN37000A

Ver. AEB

—V0.5—0—

VREADL

VDIMCLKL

VENAL

VSCLKL

VDATAINL

VCTLL

VDRSL

VSW_ONL

VSW_OFFL

VTEXCLKL

Input voltage Low-level

READ

DIMCLK

ENABLE

SCLK

DATAIN

CTL

DRS

SW_ON

SW_OFF

TEXCLK

—VVREG—2.0—VSTBYH

STBY Input voltage High-level5

—V0.5—0—VSTBYL

STBY Input voltage Low-level6

—mA5.03.62.4

Data is not transferred.

ISET = 5.1 kΩ

DAC_DATA = 80 setting

(FB : 60 mA setting)

SW_ON = SW_OFF = High

IVIN2VIN pin current 22

I/F pin

—VVREG—1.8—

VREADH

VDIMCLKH

VENAH

VSCLKH

VDATAINH

VCTLH

VDRSH

VSW_ONH

VSW_OFFH

VTEXCLKH

Input voltage High-level

READ

DIMCLK

ENABLE

SCLK

DATAIN

CTL

DRS

SW_ON

SW_OFF

TEXCLK

Circuit current

—mA4.63.52.35

Data is not transferred.

ISET = 30 kΩ

DAC_DATA = FF setting

(FB : 20 mA setting)

SW_ON = SW_OFF = High

IVIN1VIN pin current 11

Limits

Typ

Unit

Max

Notes

Min

ConditionsSymbolParameter

No.

Electrical Characteristics at VIN = 11 V, ISET = 5.1 kΩ, DAC_DATA = 80

Note) Ta=25°C±2°C unless otherwise specified.

AN37000A

Ver. AEB

—

μA

10050—Input pin = 5 V

IREADH

IDIMCLKH

IENAH

ISCLKH

IDATAINH

ICTLH

IDRSH

ISW_ONH

ISW_OFFH

ITEXCLKH

ISTBYH

Input current 1

READ

DIMCLK

ENABLE

SCLK

DATAIN

CTL

DRS

SW_ON

SW_OFF

TEXCLK

STBY

—

μA

20–2Input pin = 0 V

IREADL

IDIMCLKL

IENAL

ISCLKL

IDATAINL

ICTLL

IDRSL

ISW_ONL

ISW_OFFL

ITEXCLKL

ISTBYL

Input current 2

READ

DIMCLK

ENABLE

SCLK

DATAIN

CTL

DRS

SW_ON

SW_OFF

TEXCLK

STBY

—V0.40.270.05—

VREADHYS

VDIMCLKHYS

VENAHYS

VSCLKHYS

VDATAINHYS

VCTLHYS

VDRSHYS

VSW_ONHYS

VSW_OFFHYS

VTEXCLKHYS

Input voltage hysteresis width

READ

DIMCLK

ENABLE

SCLK

DATAIN

CTL

DRS

SW_ON

SW_OFF

TEXCLK

I/F pin (continued)

Limits

Typ

Unit

Max

Notes

Min

ConditionsSymbolParameter

No.

Electrical Characteristics (continued) at VIN = 11 V, ISET = 5.1 kΩ, DAC_DATA = 80

Note) Ta=25°C±2°C unless otherwise specified.

AN37000A

Ver. AEB

—V0.6980.6340.57DAC_DATA = 80 (TYP)VISET1

ISET pin voltage 113

—V0.54 0.450.36VCNT = defaultVref

Error amp. reference voltage

(VCNT pin voltage)

—

μA

–40–60–84

FB0 to 7 = 0.25 V

IFB0 to 7 = 60 mA

and VCNT = default (0.45 V)

EO = 2.5 V

IEO2

EO pin source current

—

μA

846040

FB0 to 7 = 0.85 V

IFB0 to 7 = 60 mA

and VCNT = default (0.45 V)

EO = 2.5 V

IEO1

EO pin sink current

Error amp. block

—V3.4 32.6—VCTWH

CTW pin High-level25

—V1.8 1.51.2—VCTWL

CTW pin Low-level24

—V5.554.5—VREG

VREG pin voltage

—V1.391.2641.137DAC_DATA = FF (MAX)VISET2

ISET pin voltage 2

ISET pin voltage

—V——

VREG

–1

IDO = –1 mAVDOH

DATAOUT pin output voltage

High

—V0.5——IDO = 1 mAVDOL

DATAOUT pin output voltage

Low

DATAOUT pin impedance

—%3—–3

Under the same condition as the

above, measure the difference

between the current of each

channel and the average current of

8 channels.

ΔIFB0

to ΔIFB7

FB0 to FB7 pin output current

(Relative variation between

outputs)

—

(%)

61.509

(3)

59.718

57.926

(–3)

ISET = 5.1 kΩ

DAC_DATA = 80

VFB0 to VFB7 = 0.75 V

IFB0

to IFB7

FB0 to FB7 pin output current

(Absolute variation of each output)

FB pin output current

—

μA

380250120VLX = 50 VILXLEAK

LX pin leak current (200 kΩ)

—%908270—DMAX

LX pin Max. duty20

—kHz740556400CTW pin : 120 pFFCTW

CTW pin frequency

OSC block

—

0.6 0.320.15ILX = 500 mARLX

LX pin ON resistance

LX pin

—

μA

5 0.07—VFB0 to VFB7 = 38 VIreak

FB0 to FB7 pin leak current

Output pin leak current

Limits

Typ

Unit

Max

Notes

Min

ConditionsSymbolParameterB No.

Electrical Characteristics (continued) at VIN = 11 V, ISET = 5.1 kΩ, DAC_DATA = 80

Note) Ta=25°C±2°C unless otherwise specified.

AN37000A

Ver. AEB

—V0.750.50.25

OVP_DATA= 00

Sweep OVP pin voltage, and check

FLAG pin voltage.

VOVPhys

OVP pin over-voltage protection

threshold

Hysteresis width

—V37.53634.5

Sweep VIN pin voltage, and check

SPRT pin current.

(Under abnormal conditions, SPRT

current outflow)

VOVIN

VIN pin over-voltage protection

threshold

(At the time VIN pin voltage

rises)

—V0.750.50.25

Sweep VIN pin voltage, and check

SPRT pin current.

VOVINhys

VIN pin over-voltage protection

threshold

Hysteresis width

—V1.80.80.3—VOFF

UVLOOFF pin threshold voltage38

—

kΩ

330 240150—RSOFT

SOFT pin resistance

—

μA

－6－12－21VSOFT = 0 VISOFT

SOFT pin current

Soft start block

Prohibition setting of VIN pin under-voltage protection (UVLOOFF pin)

*1A3.83.02.3—ILX

LX pin limit current37

—V3836.535

OVP_DATA = 00

Sweep OVP pin voltage, and check

FLAG pin voltage.

(Under abnormal conditions,

FLAG = Low)

VOVP

OVP pin over-voltage protection

threshold

(At the time OVP pin voltage

rises)

—

—V0.2 0.050.01

Protection modes (Open / short of

VIN over-voltage, OVP over-

voltage, TSD operation, DC/DC

overload and LED),

Pull-up to 5 V through 100 kΩ.

Ireak

FLAG pin Low voltage

FLAG pin

V108.57At the time VIN pin voltage risesVUVLO1

UVLO stop voltage29

V1.250.80.5

Measuring the differential voltage

between the voltage of B No.27

and the threshold voltage of UVLO

(when VIN pin voltage is falling).

VΔUVLO1

UVLO hysteresis width30

—V1.901.661.40

LED_DET = 2’b10

FB1 = 0.54 V, FB2 to 7 = 1.0 V

Sweep FB0 pin voltage, and check

FLAG pin voltage.

VFBIR

FB pin threshold for LED

abnormal detection

(Voltage difference between

max FB pin voltage and min FB

pin voltage)

LED short / open detection

Over-current protection (LX pin)

Over-voltage protection (DC/DC output, VIN input)

UVLO (VIN pin under-voltage lock-out protection) block

Limits

Typ

Unit

Max

Notes

Min

ConditionsSymbolParameter

No.

Electrical Characteristics (continued) at VIN = 11 V, ISET = 5.1 kΩ, DAC_DATA = 80

Note) Ta=25°C±2°C unless otherwise specified.

注) *1 : The threshold current at the time that the current is gradually input is shown.

In the case of actual operation, the limit current becomes higher due to circuit response delay etc.

AN37000A

Ver. AEB

—V

VIN

–5.9

VIN

–6.9

VIN

–7.9

(VIN – OVP) = 1.7 VVFAULTL

FAULT pin Low voltage

—V

VIN

+0.2

VIN

–0.4

(VIN – OVP) = 3.3 VVFAULTH

FAULT pin High voltage

—V3.32.51.7

When OVP pin voltage rises and

FAULT pin switches from High

to Low, measure the voltage of

VIN – OVP.

V(VIN-OVP)

(VIN－OVP) voltage when

switching FAULT pin

FAULT block

MaxTyp

Notes

Unit

Min

Limits

ConditionsSymbolParameterB No.

—

μA

–7.5–12.5–17.5

Overload protection operation,

SPRT = 0 V

ISPRT2

SPRT pin current 244

—

μA

–15–25–35

VIN pin over-voltage, SPRT = 0

ISPRT1

SPRT pin current 143

—V1.51.251

When SPRT pin voltage rises and

the timer latch starts, measure the

SPRT pin voltage.

VSPRT

SPRT pin threshold voltage42

—

kΩ

350250128—RSPRT

SPRT pin resistance

Timer latch block

Electrical Characteristics (continued) at VIN = 11 V, ISET = 5.1 kΩ, DAC_DATA = 80

Note) Ta=25°C±2°C unless otherwise specified.

AN37000A

Ver. AEB

Technical Data

yPD⎯Tadiagram

AN37000A

Ver. AEB

ySpecial attention and precaution in using

1. This IC is intended to be used for general electronic equipment [LED driver for LCD TV backlight].

Consult our sales staff in advance for information on the following applications:

xSpecial applications in which exceptional quality and reliability are required, or if the failure or malfunction of this IC may

directly jeopardize life or harm the human body.

xAny applications other than the standard applications intended.

(1) Space appliance (such as artificial satellite, and rocket)

(2) Traffic control equipment (such as for automobile, airplane, train, and ship)

(3) Medical equipment for life support

(4) Submarine transponder

(5) Control equipment for power plant

(6) Disaster prevention and security device

(7) Weapon

(8) Others : Applications of which reliability equivalent to (1) to (7) is required

2. Pay attention to the direction of LSI. When mounting it in the wrong direction onto the PCB (printed-circuit-board), it might

smoke or ignite.

3. Pay attention in the PCB (printed-circuit-board) pattern layout in order to prevent damage due to short circuit between pins. In

addition, refer to the Pin Description for the pin configuration.

4. Perform a visual inspection on the PCB before applying power, otherwise damage might happen due to problems such as a solder-

bridge between the pins of the semiconductor device. Also, perform a full technical verification on the assembly quality, because

the same damage possibly can happen due to conductive substances, such as solder ball, that adhere to the LSI during

transportation.

5. Take notice in the use of this product that it might break or occasionally smoke when an abnormal state occurs such as output pin-

VCC short (Power supply fault), output pin-GND short (Ground fault), or output-to-output-pin short (load short) .

And, safety measures such as an installation of fuses are recommended because the extent of the above-mentioned damage and

smoke emission will depend on the current capability of the power supply.

6. When designing your equipment, comply with the range of absolute maximum rating and the guaranteed operating conditions

(operating power supply voltage and operating environment etc.). Especially, please be careful not to exceed the range of absolute

maximum rating on the transient state, such as power-on, power-off and mode-switching. Otherwise, we will not be liable for any

defect which may arise later in your equipment.

Even when the products are used within the guaranteed values, take into the consideration of incidence of break down and failure

mode, possible to occur to semiconductor products. Measures on the systems such as redundant design, arresting the spread of fire

or preventing glitch are recommended in order to prevent physical injury, fire, social damages, for example, by using the products.

7. When using the LSI for new models, verify the safety including the long-term reliability for each product.

8. When the application system is designed by using this LSI, be sure to confirm notes in this book.

Be sure to read the notes to descriptions and the usage notes in the book.

9. As for the LED short detection function, pay attention to the constraint conditions shown in page 35. When using this IC except

the constraint condition, this IC might not detect the short condition due to the variation of diffusion or the temperature of chip.

10. Use the external components of DC/DC converter which has the recommended constant shown in page 4. Specially, the

electrolytic capacitor between the DC/DC output and GND should be 220 μF.

Moreover, the capacitor between Pin 51 (VREG) and GND should be used a ceramic capacitor of 1 μF. The wire between Pin 51

(VREG) and Pin 50 (VREGIN) should be low impedance.

Usage Notes

AN37000A

Ver. AEB

ySpecial attention and precaution in using (continued)

11. An external resistor of Pin 46 (ISET) should be placed to connect to GND pin and ISET pin on the shortest wire.

If this resistor has an unnecessary resistance (wire resistance), the current of Pin 25 to Pin 32 (FB0 to 7) shift.

If an external element of ISET pin has an unnecessary capacitance or ISET pin voltage gets noise, the oscillation occurs in the

feedback system of DC/DC converter and the current of Pin 25 to Pin 32 (FB0 to 7) fluctuates.

12. Raise VIN voltage slowly. take time more than 3ms. then, be the current flow within the limit in external components and IC.

13. When FB currents are regulated by serial control, if CH_EN function is operated (shown in page 32, 33) , it is possible to make

those FB pins open. because those FB pins are not active.

but when Full-on mode is set (by SW_ON=high and SW_OFF=high, shown in page 26), even if CH_EN function is operated,

don't open those FB pins. because those FB pins are active.

14. Pin 9 should be basically set to GND connection or open.

When Pin 9 is set to High (VREG) so UVLO_VIN function is not active, be sure to set Pin 56 (STBY) to Low at power-on /

power-off of VIN pin. (Refer to page 25 for power-on / power-off.)

15. When an external synchronous signal is input to Pin 55 (TEXCLK), start the input under the condition of Pin 56 (STANBY) =

Low before DC/DC converter is turned on. Moreover, stop the input under the condition of Pin 56 (STANBY) = Low after the

DC/DC converter is turned off.

When the external synchronous signal is input during the DC/DC converter operation, the abnormal operation, such as the

overshoot of DC/DC converter output, might occur.

16. LX pin limit current

LX pin is connected with an over-current protection circuit. When the current increases slowly, the threshold is 3 A – 0.7 A to 3 A

+ 0.8 A. However, the threshold becomes a little higher due to the delay of circuit on the actual operation.

In the case of VIN = 11 V, L = 10 mH of recommended conditions, note that the threshold becomes higher 0.2 A to 0.3 A than the

above-mentioned value.

Usage Notes (continued)

yNotes of Power LSI

1. The protection circuit is for maintaining safety against abnormal operation. Therefore, the protection circuit should not work

during normal operation.

Especially for the thermal protection circuit, if the area of safe operation or the absolute maximum rating is momentarily exceeded

due to output pin to VCC short (Power supply fault), or output pin to GND short (Ground fault), the LSI might be damaged before

the thermal protection circuit could operate.

2. Unless specified in the product specifications, make sure that negative voltage or excessive voltage are not applied to the pins

because the device might be damaged, which could happen due to negative voltage or excessive voltage generated during the ON

and OFF timing when the inductive load of a motor coil or actuator coils of optical pick-up is being driven.

3. The product which has specified ASO (Area of Safe Operation) should be operated in ASO.

4. Verify the risks which might be caused by the malfunctions of external components.

Request for your special attention and precautions in using the technical information and

semiconductors described in this book

(1) If any of the products or technical information described in this book is to be exported or provided to non-residents, the laws and

regulations of the exporting country, especially, those with regard to security export control, must be observed.

(2) The technical information described in this book is intended only to show the main characteristics and application circuit examples

of the products. No license is granted in and to any intellectual property right or other right owned by Panasonic Corporation or any

other company. Therefore, no responsibility is assumed by our company as to the infringement upon any such right owned by any

other company which may arise as a result of the use of technical information described in this book.

(3) The products described in this book are intended to be used for general applications (such as office equipment, communications

equipment, measuring instruments and household appliances), or for specific applications as expressly stated in this book.

Consult our sales staff in advance for information on the following applications:

– Special applications (such as for airplanes, aerospace, automotive equipment, traffic signaling equipment, combustion equipment,

life support systems and safety devices) in which exceptional quality and reliability are required, or if the failure or malfunction of

the products may directly jeopardize life or harm the human body.

It is to be understood that our company shall not be held responsible for any damage incurred as a result of or in connection with

your using the products described in this book for any special application, unless our company agrees to your using the products in

this book for any special application.

(4) The products and product specifications described in this book are subject to change without notice for modification and/or im-

provement. At the final stage of your design, purchasing, or use of the products, therefore, ask for the most up-to-date Product

Standards in advance to make sure that the latest specifications satisfy your requirements.

(5) When designing your equipment, comply with the range of absolute maximum rating and the guaranteed operating conditions

(operating power supply voltage and operating environment etc.). Especially, please be careful not to exceed the range of absolute

maximum rating on the transient state, such as power-on, power-off and mode-switching. Otherwise, we will not be liable for any

defect which may arise later in your equipment.

Even when the products are used within the guaranteed values, take into the consideration of incidence of break down and failure

mode, possible to occur to semiconductor products. Measures on the systems such as redundant design, arresting the spread of fire

or preventing glitch are recommended in order to prevent physical injury, fire, social damages, for example, by using the products.

(6) Comply with the instructions for use in order to prevent breakdown and characteristics change due to external factors (ESD, EOS,

thermal stress and mechanical stress) at the time of handling, mounting or at customer's process. When using products for which

damp-proof packing is required, satisfy the conditions, such as shelf life and the elapsed time since first opening the packages.

(7) This book may be not reprinted or reproduced whether wholly or partially, without the prior written permission of our company.

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