DATA SHEET Part No. AN37000A Package Code No. HSOP056-P-0300B Publication date: November 2010 Ver. AEB 1 AN37000A 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 y PD Ta diagram .............................................................................................................. 14 Usage Notes ....................................................................................................................... 15 y Special attention and precaution in using .................................................................................. 15 y Notes of Power LSI ............................................................................................................. 16 Ver. AEB 2 AN37000A 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 y LED driver IC with 8-channel constant current output y LED drive current capability of each channel : 85 mA y All the constant current of each channel can be set by one external resistor. (Pin ISET) y Built-in 8-bit DAC which can set the constant current of all channels y It is possible to control 12-bit PWM duty by serial I/F. y It 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) y Built-in various protection functions x Thermal shutdown protection x Over-voltage protection x Over-current protection x LED abnormal detection x Under-voltage lock-out protection for power supply pin etc. y Built-in 5 V regulator for internal circuits of IC y The switching frequency of DC/DC converter is synchronized with an external signal (Pin TEXCLK) Applications y LED backlight for LCD TV, LCD monitor Package y 56 pin Plastic Small Outline Package With Heat Sink (SOP Type) Type y Bi-CDMOS IC Ver. AEB 3 AN37000A Application Circuit Example (Block Diagram) 120 pF 100 220 F 11 V 10 H LX 6 VREG VREG FAULT 5 4 VIN 100 k OVP 2 3 TEXCLK CTW FLAG 55 54 53 52 STBY 56 1 STBY 7 Ceramic capacitor 1 F (5 V) 51 OSC VREG 50 VREGIN VREG GND3 UVLOOFF PREDRV 8 COMP LOG 9 48 GND1(1) DAC FAULT DETECTION, OVP, UVLO, LED_DET, CUR_LIM, TSD READ 10 49 BGR 47 TIMER LATCH AMP DIMCLK (Reference CLK11 for setting Duty) Serial control ENABLE 46 TSD 12 44 SPRT DRS GND4(1) GND4(2) 0.0082 F LOGIC BLOCK DATAIN 14 CTL 43 SW_ON SW_OFF EO 3.0 k 0.47 F 15 42 CGND2 16 41 17 SOFT 1 F 40 DATAOUT CURRENT SOURCE 18 39 19 38 20 37 21 VREG 5.1 k ISET VCNT 45 (OPEN setting) AMP SCLK 13 CGND1 GND2 GND4(4) GND4(3) GND1(2) 36 CH0 CH1 CH2 CH3 CH4 CH5 CH6 CH7 22 35 23 34 24 25 26 FB0 27 FB1 28 FB2 29 FB3 30 FB4 31 FB5 32 FB6 33 FB7 Notes) y This 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. y This block diagram is for explaining functions. Part of the block diagram may be omitted, or it may be simplified. y Use a resistor with high accuracy as an external resistor of Pin 46 (ISET) in order to set FB pin current to high accuracy. y In the case of the set which does not use SW_ON, SW_OFF pin, set these pins as the above-mentioned figure. Ver. AEB 4 AN37000A Pin Descriptions Pin No. Pin name Type Description 1 OVP Input DC/DC output voltage detection 2 N.C. -- 3 VIN 4 FAULT 5 N.C. -- 6 LX Output 7 N.C. -- 8 GND3 9 UVLOOFF Input Input pin to prohibit VIN under-voltage protection (High : Prohibition) 10 READ Input Internal serial data read mode switching (High : Read) 11 DIMCLK Input Reference clock signal input for setting duty of driving LED 12 ENABLE Input Enable signal input 13 SCLK Input Serial clock signal input 14 DATAIN Input Serial data signal input 15 CGND1 -- 16 CTL Input Latch signal input 17 DRS Input Serial setting mode switching (Low : Duty setting, High : DAC and the others setting) 18 GND4(1) Ground Power GND only for FB pin 19 GND4(2) Ground Power GND only for FB pin 20 N.C. -- N.C. 21 N.C. -- N.C. 22 SW_ON Input LED forced ON input (At SW_OFF = High, High : Forced ON) 23 SW_OFF Input LED forced OFF input (Low : forced OFF) 24 N.C. -- 25 FB0 Output LED cathode drive output 0 26 FB1 Output LED cathode drive output 1 27 FB2 Output LED cathode drive output 2 28 FB3 Output LED cathode drive output 3 29 FB4 Output LED cathode drive output 4 30 FB5 Output LED cathode drive output 5 31 FB6 Output LED cathode drive output 6 32 FB7 Output LED cathode drive output 7 33 N.C. -- N.C. 34 N.C. -- N.C. 35 N.C. -- N.C. N.C. Power supply Power supply input Output Ground External PMOS gate control N.C. Inductor drive N.C. Power GND for LX pin COM GND1 N.C. Ver. AEB 5 AN37000A Pin Descriptions (continued) Pin No. Pin name 36 N.C. 37 Type Description -- N.C. GND1(2) Ground GND 38 GND4(3) Ground Power GND only for FB pin 39 GND4(4) Ground Power GND only for FB pin 40 DATAOUT Output Serial data output 41 SOFT -- External capacitor connection pin for soft start 42 CGND2 -- COM GND2 43 EO -- External component connection pin for DC/DC phase compensation 44 SPRT -- External capacitor connection pin for timer of protection function 45 VCNT Output 46 ISET -- 47 GND2 Ground GND for setting LED current 48 GND1(1) Ground Main GND 49 N.C. 50 VREGIN 51 VREG 52 N.C. 53 FLAG Output 54 CTW -- 55 TEXCLK Input External synchronous input for setting DC/DC switching frequency 56 STBY Input Standby switching input (High : Normal operation, Low : Standby) -- Input Output -- Error amp. reference voltage output (default : OPEN) External resistor connection pin for setting LED current N.C. Power supply input for logic (Connect with VREG pin externally.) External capacitor connection pin for internal stabilized power supply (5 V) (Ceramic capacitor : 1 F) N.C. Abnormal condition detection output (High : Normal, Low : Abnormal) Note) Open-drain Triangular wave generation for setting DC/DC switching frequency (External : 120 pF) Ver. AEB 6 AN37000A 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. A No. Parameter Symbol Rating Unit Notes 1 Supply voltage VIN 38 V *1 2 Supply current IVIN -- A -- 3 Power dissipation PD 457 mW *2 4 Operating ambient temperature Topr -40 to +85 C *3 5 Storage temperature Tstg -55 to +150 C *3 6 FB pin current IFB0ABS to IFB7ABS 160 mA *3 7 Junction temperature Tj +150 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 = 85C for the independent (unmounted) IC package without a heat sink. When using this IC, refer to * PD-Ta diagram 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 = 25C. *4 : Refer to Allowable Current and Voltage Range for the allowable voltage and current of each pin. Operating Supply Voltage Range Parameter Supply voltage range Symbol Range Unit Notes VIN 10 to 34 V *1*2 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 25C ). However, since UVLO_VIN function is OFF, be sure to obey Usage Notes shown in No.14. Recommended Use Conditions Parameter Symbol Range Unit Notes VOVP VIN to 35 V -- VFB0 to VFB7 0.4 to 2 V -- FB pin current 1 (duty 100%) IFB0 to IFB7 10 to 85 mA -- FB pin current 2 (duty 50%) IFB0MAX to IFB7MAX 10 to 120 mA -- fSCLK 10 MHz -- fDIMCLK 10 MHz -- OVP pin voltage (DC/DC output) FB pin voltage (FB pin current : ON) SCLK pin frequency DIMCLK pin frequency Ver. AEB 7 AN37000A Allowable Current and Voltage Range Notes) y Allowable 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. y Voltage 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. y Do not apply external currents or voltages to any pin not specifically mentioned. y For the circuit currents, "+" denotes current flowing into the IC, and "-" denotes current flowing out of the IC. Pin No. Pin name Rating Unit Notes Pin No. Pin name Rating Unit Notes 1 OVP - 0.3 to 50 V -- 6 LX 0 to 3 A -- 4 FAULT - 0.3 to 38 V *2 25 FB0 0 to 160 mA -- 6 LX - 0.3 to 50 V *2 26 FB1 0 to 160 mA -- 9 UVLOOFF - 0.3 to VREG V *1 27 FB2 0 to 160 mA -- 10 READ - 0.3 to VREG V *1 28 FB3 0 to 160 mA -- 11 DIMCLK - 0.3 to VREG V *1 29 FB4 0 to 160 mA -- 12 ENABLE - 0.3 to VREG V *1 30 FB5 0 to 160 mA -- 13 SCLK - 0.3 to VREG V *1 31 FB6 0 to 160 mA -- 14 DATAIN - 0.3 to 5.5 V *1 32 FB7 0 to 160 mA -- 16 CTL - 0.3 to VREG V *1 40 DATAOUT -1 to 1 mA -- 17 DRS - 0.3 to VREG V *1 22 SW_ON - 0.3 to VREG V *1 23 SW_OFF - 0.3 to VREG V *1 25 FB0 - 0.3 to 38 V -- 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. 26 FB1 - 0.3 to 38 V -- 27 FB2 - 0.3 to 38 V -- 28 FB3 - 0.3 to 38 V -- 29 FB4 - 0.3 to 38 V -- 30 FB5 - 0.3 to 38 V -- 31 FB6 - 0.3 to 38 V -- 32 FB7 - 0.3 to 38 V -- 40 DATAOUT - 0.3 to VREG V *1, 2 41 SOFT - 0.3 to VREG V *1, 2 45 VCNT - 0.3 to VREG V *1 46 ISET - 0.3 to VREG V *1, 2 50 VREGIN - 0.3 to VREG V *1, 3 51 VREG - 0.3 to 6 V *2 53 FLAG - 0.3 to VREG V *1, 2 54 CTW - 0.3 to VREG V *1, 2 55 TEXCLK - 0.3 to VREG V *1 56 STBY - 0.3 to VREG V *1 Ver. AEB 8 AN37000A Electrical Characteristics at VIN = 11 V, ISET = 5.1 k, DAC_DATA = 80 Note) Ta = 25C2C unless otherwise specified. B No. Parameter Symbol Limits Unit Notes 4.6 mA -- 3.6 5.0 mA -- 1.8 -- VREG V -- -- 0 -- 0.5 V -- Conditions Min Typ Max IVIN1 Data is not transferred. ISET = 30 k DAC_DATA = FF setting (FB : 20 mA setting) SW_ON = SW_OFF = High 2.35 3.5 IVIN2 Data is not transferred. ISET = 5.1 k DAC_DATA = 80 setting (FB : 60 mA setting) SW_ON = SW_OFF = High 2.4 -- Circuit current 1 2 VIN pin current 1 VIN pin current 2 I/F pin 3 Input voltage High-level READ DIMCLK ENABLE SCLK DATAIN CTL DRS SW_ON SW_OFF TEXCLK VREADH VDIMCLKH VENAH VSCLKH VDATAINH VCTLH VDRSH VSW_ONH VSW_OFFH VTEXCLKH 4 Input voltage Low-level READ DIMCLK ENABLE SCLK DATAIN CTL DRS SW_ON SW_OFF TEXCLK VREADL VDIMCLKL VENAL VSCLKL VDATAINL VCTLL VDRSL VSW_ONL VSW_OFFL VTEXCLKL 5 STBY Input voltage High-level VSTBYH -- 2.0 -- VREG V -- 6 STBY Input voltage Low-level VSTBYL -- 0 -- 0.5 V -- Ver. AEB 9 AN37000A Electrical Characteristics (continued) at VIN = 11 V, ISET = 5.1 k, DAC_DATA = 80 Note) Ta = 25C2C unless otherwise specified. B No. Parameter Symbol Conditions Limits Unit Notes 0.4 V -- 50 100 A -- 0 2 A -- Min Typ Max 0.05 0.27 Input pin = 5 V -- Input pin = 0 V -2 I/F pin (continued) 7 Input voltage hysteresis width READ DIMCLK ENABLE SCLK DATAIN CTL DRS SW_ON SW_OFF TEXCLK 8 Input current 1 READ DIMCLK ENABLE SCLK DATAIN CTL DRS SW_ON SW_OFF TEXCLK STBY IREADH IDIMCLKH IENAH ISCLKH IDATAINH ICTLH IDRSH ISW_ONH ISW_OFFH ITEXCLKH ISTBYH 9 Input current 2 READ DIMCLK ENABLE SCLK DATAIN CTL DRS SW_ON SW_OFF TEXCLK STBY IREADL IDIMCLKL IENAL ISCLKL IDATAINL ICTLL IDRSL ISW_ONL ISW_OFFL ITEXCLKL ISTBYL VREADHYS VDIMCLKHYS VENAHYS VSCLKHYS VDATAINHYS VCTLHYS VDRSHYS VSW_ONHYS VSW_OFFHYS VTEXCLKHYS -- Ver. AEB 10 AN37000A Electrical Characteristics (continued) at VIN = 11 V, ISET = 5.1 k, DAC_DATA = 80 Note) Ta = 25C2C unless otherwise specified. B No. Parameter Symbol Conditions Limits Min Typ Max Unit Notes DATAOUT pin impedance 10 DATAOUT pin output voltage Low VDOL IDO = 1 mA -- -- 0.5 V -- 11 DATAOUT pin output voltage High VDOH IDO = -1 mA VREG -1 -- -- V -- 4.5 5 5.5 V -- VREG pin voltage 12 VREG pin voltage VREG -- ISET pin voltage 13 ISET pin voltage 1 VISET1 DAC_DATA = 80 (TYP) 0.57 0.634 0.698 V -- 14 ISET pin voltage 2 VISET2 DAC_DATA = FF (MAX) 1.137 1.264 1.39 V -- IFB0 to IFB7 ISET = 5.1 k DAC_DATA = 80 VFB0 to VFB7 = 0.75 V 57.926 (-3) 59.718 61.509 (3) mA (%) -- IFB0 to IFB7 Under the same condition as the above, measure the difference between the current of each channel and the average current of 8 channels. -3 -- 3 % -- -- 0.07 5 A -- 0.15 0.32 0.6 -- 120 250 380 A -- 70 82 90 % -- 0.36 0.45 0.54 V -- FB pin output current 15 FB0 to FB7 pin output current (Absolute variation of each output) 16 FB0 to FB7 pin output current (Relative variation between outputs) Output pin leak current FB0 to FB7 pin leak current Ireak VFB0 to VFB7 = 38 V 18 LX pin ON resistance RLX ILX = 500 mA 19 LX pin leak current (200 k) 20 LX pin Max. duty 17 LX pin ILXLEAK VLX = 50 V DMAX -- Error amp. block 21 22 23 Error amp. reference voltage (VCNT pin voltage) EO pin sink current EO pin source current Vref VCNT = default IEO1 FB0 to 7 = 0.85 V IFB0 to 7 = 60 mA and VCNT = default (0.45 V) EO = 2.5 V 40 60 84 A -- IEO2 FB0 to 7 = 0.25 V IFB0 to 7 = 60 mA and VCNT = default (0.45 V) EO = 2.5 V -84 -60 -40 A -- OSC block 24 CTW pin Low-level VCTWL -- 1.2 1.5 1.8 V -- 25 CTW pin High-level VCTWH -- 2.6 3 3.4 V -- 26 CTW pin frequency FCTW 400 556 740 kHz -- CTW pin : 120 pF Ver. AEB 11 AN37000A Electrical Characteristics (continued) at VIN = 11 V, ISET = 5.1 k, DAC_DATA = 80 Note) Ta = 25C2C unless otherwise specified. B No. Parameter Limits Unit Notes 6 A -- 240 330 k -- 7 8.5 10 V -- Measuring the differential voltage between the voltage of B No.27 and the threshold voltage of UVLO (when VIN pin voltage is falling). 0.5 0.8 1.25 V -- Ireak Protection modes (Open / short of VIN over-voltage, OVP overvoltage, TSD operation, DC/DC overload and LED), Pull-up to 5 V through 100 k. 0.01 0.05 0.2 V -- VFBIR LED_DET = 2'b10 FB1 = 0.54 V, FB2 to 7 = 1.0 V Sweep FB0 pin voltage, and check FLAG pin voltage. 1.40 1.66 1.90 V -- 35 36.5 38 V -- Symbol Conditions Min Typ Max 21 12 150 Soft start block 27 SOFT pin current ISOFT 28 SOFT pin resistance RSOFT VSOFT = 0 V -- UVLO (VIN pin under-voltage lock-out protection) block 29 30 UVLO stop voltage UVLO hysteresis width VUVLO1 VUVLO1 At the time VIN pin voltage rises FLAG pin 31 FLAG pin Low voltage LED short / open detection 32 FB pin threshold for LED abnormal detection (Voltage difference between max FB pin voltage and min FB pin voltage) Over-voltage protection (DC/DC output, VIN input) 33 OVP pin over-voltage protection threshold (At the time OVP pin voltage rises) VOVP OVP_DATA = 00 Sweep OVP pin voltage, and check FLAG pin voltage. (Under abnormal conditions, FLAG = Low) 34 OVP pin over-voltage protection threshold Hysteresis width VOVPhys OVP_DATA= 00 Sweep OVP pin voltage, and check FLAG pin voltage. 0.25 0.5 0.75 V -- 35 VIN pin over-voltage protection threshold (At the time VIN pin voltage rises) VOVIN Sweep VIN pin voltage, and check SPRT pin current. (Under abnormal conditions, SPRT current outflow) 34.5 36 37.5 V -- 36 VIN pin over-voltage protection threshold Hysteresis width VOVINhys Sweep VIN pin voltage, and check SPRT pin current. 0.25 0.5 0.75 V -- ILX -- 2.3 3.0 3.8 A *1 0.3 0.8 1.8 V -- Over-current protection (LX pin) 37 LX pin limit current Prohibition setting of VIN pin under-voltage protection (UVLOOFF pin) 38 UVLOOFF pin threshold voltage VOFF -- ) *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. Ver. AEB 12 AN37000A Electrical Characteristics (continued) at VIN = 11 V, ISET = 5.1 k, DAC_DATA = 80 Note) Ta = 25C2C unless otherwise specified. B No. Parameter Symbol Conditions 39 (VINOVP) voltage when switching FAULT pin V(VIN-OVP) When OVP pin voltage rises and FAULT pin switches from High to Low, measure the voltage of VIN - OVP. 40 FAULT pin High voltage VFAULTH 41 FAULT pin Low voltage VFAULTL Limits Unit Notes 3.3 V -- VIN VIN + 0.2 V -- VIN - 7.9 VIN - 6.9 VIN - 5.9 V -- Min Typ Max 1.7 2.5 (VIN - OVP) = 3.3 V VIN - 0.4 (VIN - OVP) = 1.7 V FAULT block Timer latch block 42 SPRT pin threshold voltage VSPRT When SPRT pin voltage rises and the timer latch starts, measure the SPRT pin voltage. 1 1.25 1.5 V -- 43 SPRT pin current 1 ISPRT1 VIN pin over-voltage, SPRT = 0 V -35 -25 -15 A -- 44 SPRT pin current 2 ISPRT2 Overload protection operation, SPRT = 0 V -17.5 -12.5 -7.5 A -- 45 SPRT pin resistance RSPRT 128 250 350 k -- -- Ver. AEB 13 AN37000A Technical Data y PD Ta diagram Ver. AEB 14 AN37000A Usage Notes y Special 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: x Special 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. x Any 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 solderbridge 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 pinVCC 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 F. Moreover, the capacitor between Pin 51 (VREG) and GND should be used a ceramic capacitor of 1 F. The wire between Pin 51 (VREG) and Pin 50 (VREGIN) should be low impedance. Ver. AEB 15 AN37000A Usage Notes (continued) y Special 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. y Notes 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. Ver. AEB 16 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 improvement. 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. 20100202