BD555A1AFV Datasheet LED Driver for Lighting Series Electrolytic Capacitor Free Buck Converter LED Driver BD555A1AFV ●General Description BD555A1AFV is a LED driver best for LED lighting applications. It supports dimming. Constant current switching controller for AC/DC buck converter is accumulated inside. By choosing external MOS Transistor, small～large power of LED can be driven. The driver is adoptable to a wide range of lighting from small light such as spotlights to large one like base lights. With digital power control, the average value of LED current is stably adjustable to requesting current. By only primary sense resistor, LED current is available to feedback LED current is useful without feedback circuits, reduce parts. Input characteristics and output characteristics is good by precisely digital power control. It’s support electrolytic free design by capacitor controller which is detect AC voltage and control ceramic capacitor. ●Key Specifications ■ AC Input range ■ Input Voltage range(AUX pin) ■ Operating temperature ■ Accuracy of output current ●Features ■ Highly efficient Buck AC/DC converter ■ Primary control without feedback circuit ■ High accuracy LED current output by LED average control ■ Capacitor controller for Electrolytic free design ■ Fixed switching frequency ■ Built-in regulator for inner power supply ■ Built-in LED open detection (shutdown type) ■ Built-in UVLO detection ■ Built-in thermal shut-down function ●Packages SSOP-B14 5.00mm×6.40mm×1.15mm ●Applications ■ Spot light without dimming ■ Desk ramp without dimming ■ Down light without dimming ■ Base light without dimming 80 to 275VAC 10 to 38V -40 to 100℃ ±1.5 %( Typ.) ●Typical Application Circuits RAUX1:200kΩ VBUCK RAUX2:1kΩ Cout: 0.1µF TR3 CAC: 10µF D AUX1:15V DAUX2 DFLY VLED LA: 0.2mH DBUCK CVDD2: 2.2µF CAUX: 0.47µF VDD2 LP: 2mH AUX VDET DVDD DVDD2 VDD2 VDD1 VOUT CVDD1: 2.2µF TR1 CSEL ISENSE TESTO GNDA SOFT RSOFT: 100kΩ Fig.1 GND OSC RISET: 1.5Ω ROSC: 100kΩ Typical Application Circuit ○Product structure：Silicon monolithic integrated circuit ○This product is not designed protection against radioactive rays .www.rohm.com TSZ02201-0F2F0C300010-1-2 © 2012 ROHM Co., Ltd. All rights reserved. 1/15 TSZ22111・14・001 03.AUG.2012 Rev.001 Datasheet BD555A1AFV ●Absolute Maximum Ratings (Ta=25°C) Parameter Symbol Ratings Unit Maximum Applied Voltage 1 VMAX1 4.5 V Maximum Applied Voltage 2 VMAX2 15.5 V Maximum Applied Voltage 3 *1 Allowable Power Dissipation Operating Temperature Storage temperature VMAX3 Pd1 Topr Tstg 40.0 874.7 -40 ～ +100 -55 ～ +150 V mW ℃ ℃ *1 Conditions VDD2, DVDD, DVDD2, OSC, SOFT, ISENSE PIN VDET, VDD1, VOUT, CSEL, TESTO PIN AUX PIN When being mounted on 1 layer substrate(ROHM typical board). Copper layer area is 20.2mm2. When being used at over Ta=25°C, Pd1 decreases by about 7.00mW/°C. ●Recommended Operating Range (Ta=-40°C ~ +100°C) Parameter Operating supply voltage Symbol AUX Min. 10 Ratings Typ. 16 Max. 38 ●Electrical Characteristics (Unless specified, AUX=16V, Ta = +25°C) Ratings Parameter Symbol Min. Typ. Max. [Circuit Current] Operating Current 1 7.0 14.0 22.0 Idd1 1.5 2.5 3.5 Operating Current 2 Idd2 [Regulator] VDD1 Voltage VDD1 Low Voltage Detection Voltage VDD2 Voltage AUX Start-Up Voltage AUX Low Voltage Detection Voltage [Switching Regulator] Oscillating Frequency Maximum Duty Average Current Sense Voltage Current Sense Blank-Time VOUT High On-Resistance VOUT Low On-Resistance [Capacitor Controller] AC Input “H” Detection Voltage AC Input “L” Detection Voltage VDET Input Voltage Range CSEL On-Resistance CSEL Off-Leakage Unit Conditions V Unit µA mA Conditions At Start-up, AUX=7.0V When stopping switching VVDD1 Vuvlo1 VVDD2 Vstup Vuvloaux 11 4.0 2.9 7.45 6.00 12 5.0 3.3 8.50 6.50 13 6.0 3.7 10.00 7.45 V V V V V Fosc Dmax Visns Tisnst Rvouth Rvoutl 90 475 360 3.0 2.0 100 75.0 500 400 7.0 4.5 110 525 440 16.0 12.0 kHz % mV nsec Ω Ω Rosc=Open Deth 340 420 500 mV When VDET is rising Detl 240 300 360 mV When VDET is falling VVDET RonCS IleakCS -0.3 - 10 - 9.0 100 1.0 V Ω µA ICSEL=2mA Sink CSEL=10V www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 2/15 With no-load When AUX is falling With no-load When AUX is rising When AUX is falling IVOUT=20mA Source IVOUT=20mA Sink TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV ● Pin Description No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 I/O 端子名称 DVDD VDET AUX VDD1 VDD2 OSC DVDD2 SOFT VOUT ISENSE GND GNDA CSEL TESTO In In In Out Out In In In Out In Out Out 機 等価回路 能 Digital Power Supply AC voltage detection PIN(for Electrolytic free) Power Supply Input Pin Regulator Output 1 / Inner Power Supply 12.0V Regulator Output 2 / Inner Power Supply 3.3V Switching Frequency Setting Pin Digital Power Supply Soft-start・Slope Time Setting Pin Switching MOS Gate Driver Pin Current Sense Pin GND Pin GND Pin Capacitor Selector Pin(for Electrolytic free) Test Output Pin ●Pin Configuration C A A C C C C C D C B D A C ● Equivalent Circuit Diagram （TOP VIEW） A DVDD 1 14 TESTO VDET 2 13 CSEL AUX 3 B AUX D GND 12 GNDA VDD1 4 11 GND VDD2 5 10 ISENSE OSC 6 9 VOUT DVDD2 7 8 SOFT C AUX Fig.2 Pin Configuration Fig.3 Equivalent Circuit Diagram ●Block Diagram DVDD AUX Capacitor Control VDET + CSEL Capacitor Control LOGIC Dimming Control TESTO Power Supply Protection Circuit TSD - UVLO SCP LED Open VREF SOFT Regulator VDD1 VDD2 Vo1=12.0V Vo2= 3.3V IREF Internal Power Supply LED Current Control Dimming Control LOGIC Soft Start Timer DVDD2 S VOUT Q R - ISENSE COMP + OSC OSC LED Average Current Control LOGIC GND A/D D/A GNDA Fig.4 Block Diagram www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 3/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV ●Description of Blocks 1) Regulator Regulator with output of typ.3.3V is built in, which places AUX pin at input. When AC power source is input, according to clamp voltage of Zener Diode (DAUX), power is supplied to AUX pin through start-up resistor (RAUX). Until AUX pin gets typ.8.5V, switching operation is kept stopped. Circuit current is typ.10µA, so that voltage drop of RAUX can be kept small. When AUX pin becomes typ.8.5V, switching operation starts. After the start of switching operation, it is recommended that power is supplied to AUX pin by fly-back method through transformer (LAUX). Output voltage of VDD2 is used at circuit inner power supply. When VDD2 pin becomes below typ.2.45V, UVLO detection is carried out and it leads to a non-operating state. 2) Soft Start Soft start bring good effect which is smoothing light on at power on and prevent the LED short protection in power on, if output capacitor is big. Soft start limits Duty of switching and increases the set value of LED peak current from low level by slope function. Soft start is run only one time when the AC power is supplied. When VDD2 pin detect low voltage, this function is reset and run again when next AC power source is input (when low voltage detection is canceled). AC Power Supply (50Hz/60Hz) AC line (VBUCK) VDD2: 3.3V UVLO: 8.5V AUX : 16V(Recommendation) AUX VDD1 Sampling Data (Internal Resister Value) FFH ００H Soft Start Time Dimming Decoder (Internal Resister Value) 01H 02H 03H ０0H FDH FEH FFH 100% LED Current Slope Control 0% t StartStart-Up SoftSoft-Start Normal Fig.5 Soft Start Soft start time can be set by resistor (RSOFT) connecting to SOFT pin. Soft start time, TSOFT is shown as in below chart. RSOFT , Setting of Soft-Start ／Slope Time Soft-Start／ RSOFT Slope Time 100kΩ 100msec 39kΩ 800msec 24kΩ 1600msec 0msec No Connection (No Slope) www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 4/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV 3) Digitally Controlled Switching Converter ・Operation Description of Buck Converter When AUX becomes typ.8.5V, switching controller starts its switching operation. Switching frequency is determined depending on the value of resistor (Rosc) connecting to OSC pin. At the beginning of switching cycle, FET（TR1）for switching turns ON. Coil current flows into RISET and current is detected by ISENSE pin. However even TR1 turns ON, current detection is not carried out for a definite period of time, typ.400nsec. It prevents a malfunction caused by reverse recovery current of freewheel diode (DOUT), when TR1turns ON. TR1 turns OFF, so that the voltage of ISENSE pin increases linearly and LED average current is adjusted to requested current. Switching duty(D) is generally shown as below formula, considering input voltage as VBUCK and output voltage as VLED. D= VLED VBUCK When switching duty (D) reaches to maximum 75.0% (typ.), the status is forced to change into OFF. Moreover minimum On width is 400nsec (typ.). For 400nsec, ON status is maintained compulsorily. ・Setting of LED Current Switching controller adjusts the average current of coil to a value which is set by RISET, monitoring coil current at switching “ON” from ISENSE pin. Since the average current of coil and LED current are of equivalent value, setting of LED current is determined by controlling the average current of coil. LED average current, IAVE is determined by ripple current ΔIL of coil. Peak Current is shown as below formula in continuous current mode (CCM). Compute ΔIL from the data sampled with A/D converter from ISENSE pin, and calculate peak current IPEAK, so that average current becomes requested value. Input peak current IPEAK into D/A converter and treat it as reference voltage of comparator COMP. SinceΔIL is calculated and feed-backed, average current control is available without influence of input voltage・output voltage・constant of coil・switching frequency which are change by ΔIL. I AVE = IPEAK − ∆IL 2 IPEAK ΔIL IAVE LED Current tON t tOFF Fig.6 Waveform of LED Current (in continuous current mode) VBUCK DO ut C out: 0.1µF CAC:10µF VLED LSW:1mH LED Current Control Protect VOUT S Q R - TR1 ISENSE COMP + Dimming OSC 20-300k Hz OSC ROSC: 100kΩ LED Average Current Control LOGIC RISET :1.5Ω A/D D/A GND Fig.7 Block Diagram of Average Current Control www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 5/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV LED Average Current IAVE is set by resistor (RISET) connecting ISENSE pin. Each set-up current is indicated as below formula. Setting current is chosen drive current of external MOS FET. Average current sense voltage, Visns is set to 500mV. I AVE = Visns R ISET RISET , Set-Up Examples of LED Average Current LED RISET Average Current 5.10Ω 98mA 2.00Ω 250mA 1.50Ω 333mA 1.00Ω 500mA 0.75Ω 667mA 0.68Ω 735mA Fig.8 shows input voltage characteristics when RISET is 1Ω. And Fig.9 indicates output voltage characteristics. Fig.8 Input voltage (VPRI) vs. LED Current Fig.9 Output voltage (VLED) vs. LED Current Under the following conditions, it is difficult to control average current. 1.) When On time is 400nsec. On Time, ton, is indicated as follows, considering switching frequency as fSW. VLED 1 t ON = × VBUCK fSW When input voltage is high, output voltage is low or switching frequency is high, there is a possibility that on time becomes 400nsec. Switching frequency is recommended to be set low. 2.) When switching duty (D) is 75.0%. Switching duty (D) is expressed as follows. D= VLED VBUCK When input voltage is low or output voltage is high, there is a possibility switching duty (D) exceeds 75.0%. It is necessary to keep input voltage high or make output voltage low. www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 6/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV 3.) In case of DCM（discontinuous current mode） In CCM, digitally controlled switching converter carries out average current control. In DCM, since current of section where no current flows cannot be controlled, LED current value becomes lower than set-up current value. LED Current Loss IPEAK IAVE tON tOFF t Fig.10 Waveform of LED Current (In discontinuous current mode) DCM occurs when LED set-up current is low or switching frequency is low. Switching frequency is recommended to set high. ・Setting of Switching Frequency In setting of switching frequency, a relation of trade-off holds between power efficiency and the size (price) of external components. To improve power efficiency, slower switching frequency is better but in that case, the size of external parts get bigger. Maximum switching frequency is decided by minimum ON time. Minimum ON time (tON(MIN)) is available when input voltage VBUCK is highest voltage and output voltage VLED is minimum,. It is shown as below formula. VLED (MIN) 1 × t ON(MIN) = VBUCK f (MAX) SW Switching duty (D) is simply shown as following formula. D= VLED = t ON × fSW VBUCK fSW : Switching Frequency Set switching frequency within 20kHz～300kHz. Determine it so that minimum ON time (tON(MIN)) gets more than 400nsec. Switching frequency fOSC is determined by resistor ROSC connecting to OSC pin. Each set-up frequency is indicated as below formula. However if Rosc is not connected, it is set to 100 kHz. Moreover if Rosc is short-circuit to GND, it is set to 20kHz. fOSC [kHz] = 8192 / Rosc[kΩ] ROSC Setting Example of Switching Frequency ROSC Switching Frequency 300 kΩ 28kHz 150 kΩ 50kHz 68 kΩ 120kHz 27 kΩ 300kHz No Connection 100kHz www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 7/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV ●Protection Function 1) Detection of Abnormal Temperature Thermal shut down starts to operate over 150°C(typ. ), making IC from active status to non-active status. In the non-active status, switching operation stops. Gate driver output turns into low impedance against GND. When the temperature of IC returns to normal level, IC recovers from initial mode to active mode. 2) VDD1 Low Voltage Detection When VDD1 power supply voltage is low or any abnormal status occurs such as VDD1pin short, IC is turned to non-active status from active mode, since there is a possibility that IC does not operate properly. In non-active mode, switching operation stops. Gate driver output turns into low impedance against GND. When VDD1power supply voltage returns to normal level, IC recovers from initial mode to active mode. 3) VDD2 Low Voltage Detection When VDD2 power supply voltage is low or any abnormal problem occurs such as VDD2 pin short, IC is turned to non-active mode, since there is a possibility that IC does not operate properly. In non-active mode, switching operation stops. Gate driver output turns into low impedance against GND. When VDD2power supply voltage returns to normal level, IC recovers from initial mode to active mode. 4) AUX Low Voltage Detection When AUX power supply voltage is low or any abnormal problem occurs such as AUX pin short, IC is turned non-active, since there is a possibility that IC does not operate properly. In non-active mode, switching operation stops. Gate driver output turns into low impedance against GND. When AUX power supply voltage returns to normal level, IC recovers from initial mode to active mode. 5) LED OPEN Detection IC is turned from active mode to non-active mode, when ISENSE pin voltage does not reach to average current value for 52.4msec because of LED’s OPEN defects, OPEN ISENSE pin, coil’s OPEN defects and so on. In non-active mode, switching operation stops. Gate driver output turns into low impedance against GND. LED OPEN detection holds non-active mode until VDD2 low voltage detection is carried out. IC recovers to active mode in following flow; switching operation stops → VDD2 low voltage detection works → LEDOPEN detection is re-set. 6) LED GND SHORT Detection IC is turned from active mode to non-active mode, when ISENSE pin voltage does not reach to average current value for 52.4msec because of LED’s GND SHORT defects, SHORT ISENSE pin. In non-active mode, switching operation stops. Gate driver output turns into low impedance against GND. LED OPEN detection holds non-active mode until VDD2 low voltage detection is carried out. IC recovers to active mode in following flow; switching operation stops → VDD2 low voltage detection works → LED GND SHORT detection is re-set. www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 8/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV ●Typical Performance Curves 150℃ ℃ 25℃ ℃ -40℃ ℃ 150℃ ℃ 25℃ ℃ -40℃ ℃ Fig.11 Current Consumption1 -40℃ ℃ 25℃ ℃ Fig.12 Current Consumption.2 150℃ ℃ Fig.13 VDD2 Voltage www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 Fig.14 Switching Frequency 9/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV 3σ σ:1.5% Fig.15 Average Current Sense Voltage Fig.16 Fig.17 Fig.18 Output voltage Characteristics AC Input Voltage Characteristics www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 10/15 LED Current accuracy TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV ●Application Examples 1) Basic Circuit (Buck) Connect about LEDs in series. Connect 1.5Ω resistor to RISET and set LED average current to 333mA. Select external MOS-FET depending on LED current.（recommendation：R5205CND:ROHM） Set AUX power supply to over 12.0V. At start up, power is supplied through TR3. When AUX exceeds start-up voltage 8.5V, switching operation starts. In switching operation, power is supplied via transformer. Connect VDET pin to VDD2. Connect DVDD and DVDD2 to VDD2, too. Switching frequency is set by connecting resistor between OSC pin and GND. Slope time of dimming can be set by connecting resistor between SOFT pin and GND. RAUX1:200kΩ VBUCK RAUX2:1kΩ Cout: 0.1µF TR3 CAC: 10µF D AUX1:15V DAUX2 VLED DFLY LA: 0.2mH DBUCK CVDD2: 2.2µF CAUX: 0.47µF VDD2 LP: 2mH AUX VDET VDD2 DVDD DVDD2 VDD1 CVDD1: 2.2µF TR1 VOUT CSEL ISENSE TESTO GNDA SOFT GND RISET: 1.5Ω OSC RSOFT: 100kΩ ROSC: 100kΩ Fig.19 Application Example (High-Power LED 333mA) 2) Design for more compact circuit, reducing number of components Supply power through RAUX. When AUX exceeds start-up voltage, 8.5V, switching operation starts. In steady state, set AUX voltage to over 12V. Since about 3mA power loss (0.3W: at AC100V）occurs at RAUX, efficiency gets worse compared to the basic circuit. Make OSC and SOFT pins Open. At this time, switching frequency becomes 100kHz and SOFT time is 0msec. VBUCK RAUX:33kΩ Cout: 0.1µF CAC: 10µF VLED LP: 2mH CVDD2: 2.2µF CAUX: 0.47µF VDD2 DBUCK AUX VDET DVDD DVDD2 VDD2 VDD1 VOUT CVDD1: 2.2µF TR1 CSEL ISENSE TESTO GNDA SOFT GND RSOFT: 100kΩ OSC RISET: 1.5Ω ROSC: 100kΩ Fig.20 Application Example（Miniaturization：High-Power LED 333mA） www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 11/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV 3) Circuit Example for Electrolytic free Connect VDET and CSEL pin to the “Electrolytic Capacitor Less Circuit”. This application is not used Electrolytic-capacitor, is used two ceramic-capacitor. Two capacitor controls is available to stable constant LED current, when AC input voltage is low. DAC RVDET1:1MΩ RAUX1:200kΩ Cout: 0.1µF TR3 CAC: 10µF RVDET2:10KΩ VBUCK RAUX2:1kΩ D AUX1:15V DAUX2 DFLY VLED LA: 0.2mH Electrolytic Capacitor Less Circuit DBUCK CVDD2: 2.2µF CAUX: 0.47µF VDD2 LP: 2mH AUX VDET DVDD DVDD2 VDD2 VDD1 VOUT CVDD1: 2.2µF TR1 CSEL ISENSE TESTO GNDA SOFT GND RSOFT: 100kΩ OSC RISET: 1.5Ω ROSC: 100kΩ Fig.21 Application Example（Electrolytic free：High-Power LED 333mA） www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 12/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV ●Operational Notes (1) Absolute Maximum Ratings An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc., can break down devices, thus making impossible to identify breaking mode such as a short circuit or an open circuit. If any special mode exceeding the absolute maximum ratings is assumed, consideration should be given to take physical safety measures including the use of fuses, etc. (2) Operating conditions These conditions represent a range within which characteristics can be provided approximately as expected. The electrical characteristics are guaranteed under the conditions of each parameter. (3) Power supply line Design PCB pattern to provide low impedance for the wiring between the power supply and the GND lines. In this regard, for the digital block power supply and the analog block power supply, even though these power supplies has the same level of potential, separate the power supply pattern for the digital block from that for the analog block, thus suppressing the diffraction of digital noises to the analog block power supply resulting from impedance common to the wiring patterns. For the GND line, give consideration to design the patterns in a similar manner. Furthermore, for all power supply terminals to ICs, mount a capacitor between the power supply and the GND terminal. At the same time, in order to use an electrolytic capacitor, thoroughly check to be sure the characteristics of the capacitor to be used present no problem including the occurrence of capacity dropout at a low temperature, thus determining the constant. (4) GND voltage Make setting of the potential of the GND terminal so that it will be maintained at the minimum in any operating state. Furthermore, check to be sure no terminals are at a potential lower than the GND voltage including an actual electric transient. (5) Short circuit between terminals and erroneous mounting In order to mount ICs on a set PCB, pay thorough attention to the direction and offset of the ICs. Erroneous mounting can break down the ICs. Furthermore, if a short circuit occurs due to foreign matters entering between terminals or between the terminal and the power supply or the GND terminal, the ICs can break down. (6) Operation in strong electromagnetic field Be noted that using ICs in the strong electromagnetic field can malfunction them. (7) Inspection with set PCB On the inspection with the set PCB, if a capacitor is connected to a low-impedance IC terminal, the IC can suffer stress. Therefore, be sure to discharge from the set PCB by each process. Furthermore, in order to mount or dismount the set PCB to/from the jig for the inspection process, be sure to turn OFF the power supply and then mount the set PCB to the jig. After the completion of the inspection, be sure to turn OFF the power supply and then dismount it from the jig. In addition, for protection against static electricity, establish a ground for the assembly process and pay thorough attention to the transportation and the storage of the set PCB. (8) Input terminals In terms of the construction of IC, parasitic elements are inevitably formed in relation to potential. The operation of the parasitic element can cause interference with circuit operation, thus resulting in a malfunction and then breakdown of the input terminal. Therefore, pay thorough attention not to handle the input terminals, such as to apply to the input terminals a voltage lower than the GND respectively, so that any parasitic element will operate. Furthermore, do not apply a voltage to the input terminals when no power supply voltage is applied to the IC. In addition, even if the power supply voltage is applied, apply to the input terminals a voltage lower than the power supply voltage or within the guaranteed value of electrical characteristics. www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 13/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV (9) Ground wiring pattern If small-signal GND and large-current GND are provided, It will be recommended to separate the large-current GND pattern from the small-signal GND pattern and establish a single ground at the reference point of the set PCB so that resistance to the wiring pattern and voltage fluctuations due to a large current will cause no fluctuations in voltages of the small-signal GND. Pay attention not to cause fluctuations in the GND wiring pattern of external parts as well. (10) External capacitor In order to use a ceramic capacitor as the external capacitor, determine the constant with consideration given to a degradation in the nominal capacitance due to DC bias and changes in the capacitance due to temperature, etc. (11) Thermal shutdown circuit (TSD) When junction temperatures become higher than detection temparatures, the thermal shutdown circuit operates and turns a switch OFF. The thermal shutdown circuit, which is aimed at isolating the LSI from thermal runaway as much as possible, is not aimed at the protection or guarantee of the LSI. Therefore, do not continuously use the LSI with this circuit operating or use the LSI assuming its operation. (12) Thermal design Perform thermal design in which there are adequate margins by taking into account the permissible dissipation (Pd) in actual states of use. (13) Selection of coil Select the low DCR inductors to decrease power loss for DC/DC converter. (14) The temperature range of operation guarantees functional operation only. The life of LSI is not guaranteed in this range. The life of LSI has derating according to the environment, such as Ta, humidity, Voltage and so on. In performing an apparatus design, please perform the design in consideration of life derating of LSI. (15) About the function description or technical note or more The function description and the application notebook are the design materials to design a set. So, the contents of the materials aren’t always guaranteed. Please design application by having fully examination and evaluation include the external elements. 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 www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 14/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet BD555A1AFV ●Ordering Information B D 5 5 5 A 1 A F V Package FV : SSOP-B14 Product name - E2 Packaging and forming specification E2: Embossed tape and reel ●Physical Dimension Tape and Reel Information ●Marking Diagram 555A1 A LOT No. 1PIN MARK www.rohm.com © 2012 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 15/15 TSZ02201-0F2F0C300010-1-2 03.AUG.2012 Rev.001 Datasheet Notice ●General Precaution 1) Before you use our Products, you are requested to carefully read this document and fully understand its contents. ROHM shall not be in any way responsible or liable for failure, malfunction or accident arising from the use of any ROHM’s Products against warning, caution or note contained in this document. 2) All information contained in this document is current as of the issuing date and subject to change without any prior notice. Before purchasing or using ROHM’s Products, please confirm the latest information with a ROHM sales representative. ●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, 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. 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. Notice - Rev.003 © 2012 ROHM Co., Ltd. All rights reserved. Datasheet ●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; if flow soldering method is preferred, please consult with the ROHM representative in advance. For details, please refer to ROHM Mounting specification ●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 our Products might fall under controlled goods prescribed by the applicable foreign exchange and foreign trade act, please consult with ROHM representative 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. ROHM shall not be in any way responsible or liable for infringement of any intellectual property rights or other damages arising from use of such information or data.: 2) 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 information contained in this document. Notice - Rev.003 © 2012 ROHM Co., Ltd. All rights reserved. Datasheet ●Other Precaution 1) The information contained in this document is provided on an “as is” basis and ROHM does not warrant that all information contained in this document is accurate and/or error-free. ROHM shall not be in any 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. 2) This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM. 3) The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of ROHM. 4) 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. 5) 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 - Rev.003 © 2012 ROHM Co., Ltd. All rights reserved.