BD6077GUT LED Drivers for LCD Backlights White Backlight LED Drivers for Small to Medium LCD Panels (Switching Regulator Type) BD6077GUT No.11040EAT41 ●Description The BD6077GUT is a white LED driver IC with synchronous rectification that can drive up to 3LEDs. With synchronous rectification (no external schottky diode required) and small package, they can save mount space. And the brightness of LED can be adjusted by using PWM pulse on EN pin. ●Features 1) Synchronous rectification Boost DC/DC converter 2) No external schottky diode required 3) Driving 3 series white LEDs 4) Over voltage protection 5) Protect open and short output 6) Thermal shut down 7) Brightness adjustment by external PWM pulse 8) Small and Thin CSP package in 8pins ●Applications White LED Backlight Torchlight and easy flash for camera of mobile phone ●Absolute maximum ratings (Ta=25°C) Parameter Symbol Ratings Unit Maximum applied voltage 1 VMAX1 7 *1 V Vin, EN, VFB, TEST Maximum applied voltage 2 VMAX2 20 *1 V SW, Vout Pd 750 *2 mW Operating temperature range Topr -30~+85 ℃ Storage temperature range Tstg -55~+150 ℃ Power dissipation Condition *1 These value are based on GND and GNDA pins. *2 50mm×58mm×1.75mm At glass epoxy board mounting. When it’s used by more than Ta=25 ℃, it’s reduced by 6.0mW/℃. ●Operating conditions (Ta=25°C) Parameter Power supply voltage www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. Symbol Vin Ratings Min. Typ. Max. 2.7 3.6 5.5 1/16 Unit Condition V 2011.12 - Rev.A Technical Note BD6077GUT ●Electrical characteristics Unless otherwise specified Ta =-30℃~+85℃, Vin=3.1~5.5V Limits Parameter Symbol Min. Typ. Max. Unit Condition [ EN terminal ] EN threshold voltage (Low) VthL - - 0.4 V EN threshold voltage (High) VthH 1.4 - - V Iin - 18.3 30.0 µA EN=5.5V Iout -2.0 -0.1 - µA EN=0 Quiescent Current Iq - 0.1 2.0 µA EN=TEST=VFB=0V,SW=open Current Consumption Idd - 1.0 1.5 mA EN=1.4V,TEST=0V,VFB=1.0V, SW=open Feedback voltage Vfb 0.47 0.50 0.53 V Inductor current limit Icoil 210 310 410 mA SW saturation voltage Vsat - 0.245 0.345 V Isw=200mA, Vin=3.6V SW on resistance P Ronp - 5.4 7.2 Ω Isw=200mA, Vout=10V Switching frequency fSW 0.8 1.0 1.2 MHz Duty cycle limit Duty 82.7 95.0 - % Over voltage limit Ovl 14.0 14.5 15.0 V EN terminal input current EN terminal output current [ Switching regulator ] 1 EN=1.4V,TEST=0V EN=1.2V, TEST=2.9V, Vin=3.6V,VOUT=9V (*1) EN=1.4V,TEST=0V,VFB=0V, VOUT=10V,SW=open EN=1.4V,TEST=0V,VFB=0V, VOUT=10V,SW=open EN=1.4V,TEST=0V,VFB=0V, SW=open This parameter is tested with DC measurement. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 2/16 2011.12 - Rev.A Technical Note BD6077GUT ●Test circuit *Test circuit A (for Inductor current limit, Feedback voltage.) Procedure ~Inducton current limit~ 1. Start to increase Iout from 0mA gradually. 2. You will find that Vout will start to go down and the duty will be decreased. 3. Then, you can measure the coil current as “inductor current limit” ~VFB voltage~ 1. Supply 0mA to Iout 2. Then, you can measure the VFB voltage as “Feedback voltage”. Icoil 3.1~5.5V VIN 22µH monitor A 1µF Tall Ton SW VIN VOUT Duty= Ton Tall 1µF EN Iout TEST GNDA VFB GND RFB 24Ω V Fig.1 Test Circuit A *Test circuit B (for Over voltage limit,Duty cycle limit, Switching frequency) Procedure ~Over voltage limit~ 1. Start to increase VOUT from 12V to 16V 2. You will find frequency change from around 1MHz to 0Hz 3. Then,you can measur the VOUT voltage as “Over Voltage limit” ~Duty cycle limit, Switching frequency ~ 1. Supply 9V to VOUT terminal 2. Then,you can measure the duty as “Duty cycle limit” and the frequency and “Switching frequency”. monitor 3.1~5.5V VIN Ton SW VIN VOUT 1µF 1µF EN TEST GNDA Tall Duty= Ton Tall 12V to 16V VFB GND Fig.2 Test Circuit B *TEST circuit C (for Quiescent current, current comsumption, EN Terminal input/output current, EN threshold voltage(Low/High)) ICC 3.1~5.5V 1uF A VIN SW A EN VOUT IEN 0.0~5.5V TEST TEST GNDA GND VFB 1.0V(current comsumption) Fig.3 Test Circuit C www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 3/16 2011.12 - Rev.A Technical Note BD6077GUT 1.0 4 0.8 3 Ta=85℃ 2 Ta=25℃ 1.2 1.1 Frequency [MHz] 5 IIN[uA] IIN[mA] ●Electrical characteristic curves (Reference data) 0.6 0.4 Ta=85℃ 0.2 1 1 2 3 0.9 Ta=25℃ 0.0 4 VIN[V] 5 6 0.8 1 7 Fig.4 Current consumption vs. Power supply voltage 2 3 4 5 VIN[V] 6 7 2.5 450 525 400 3 500 475 Ta=-30℃ VIN=3.6V VIN=5.5V 5 5.5 Murata : LQH32CN53L 80 350 300 VIN=3.1V 75 70 TOKO : DB3015CK 65 60 250 55 450 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 200 Ta[℃] -30 Fig.7 Feedback voltage vs. Power supply voltage -10 10 30 50 Ta [deg] Output Power[mW] VIN=3.6V VIN=4.2V 70 35 40 85 Ta=-30℃ Ta=25℃ 1000 800 Ta=85℃ 600 Ta=25℃ 65 60 25 30 Iout [mA] 35 40 Fig.10 Efficiency vs. LED current (3LED=VOUT10.5V) coil : TOKO DB3015CK www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 80 Ta=85℃ 75 Ta=25℃ 70 65 400 20 25 30 Iout[mA] 90 1200 15 20 Ta=-30℃ 80 10 15 Fig.9 Efficiency vs. LED current (4LED=VOUT14V) 1400 85 VIN=3.1V 10 Fig.8 Inductor current limit vs. Temperature VIN=5.5V 75 50 85 70 Efficiency[%] 90 Efficiency [%] 4.5 90 Efficiency[%] Inductor current [mA] VFB[mV] Ta=85℃ 4 Fig.6 Oscillation frequency vs. Power supply voltage 85 Ta=25℃ 3.5 VIN[V] Fig.5 Quiescent current vs. Power supply voltage 550 Ta=85℃ Ta=25℃ Ta=-30℃ Ta=-30℃ 0 Ta=-30℃ 1.0 60 3.0 3.2 3.4 3.6 3.8 VIN[V] 4.0 4.2 Fig.11 Output power vs. Power supply voltage coil : TOKO DB3015CK 4/16 2.7 3.1 3.5 3.9 4.3 VIN[V] 4.7 5.1 5.5 Fig.12 Efficiency vs. Power supply voltage (Load=34mA) coil : TOKO DB3015CK 2011.12 - Rev.A Technical Note BD6077GUT ●Electrical characteristic curves (Reference data) – Continued VOUT EN VOUT EN VOUT VFB Peak=208mA delta=1.68V VFB Peak=160m Iin Iin Vin=3.6V, Ta=25 oC 3LED, 34mA Load Fig.13 LED Open output voltage Fig.14 LED brightness adjustment Fig.15 Soft Start 50 500 20% 40 15% VIN=4.2V VIN=4.2V VFB[mV] VIN=3.9V 200 VIN=5.2V VFB[mV] 30 300 VIN=3.9V 20 VIN=5.2V VIN=3.1V VIN=3.1V 10 VIN=3.6V 100 10% VIN=3.6V 20 40 60 Duty[%] 80 www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 2 4 100 Fig.16 LED brightness adjustment for PWM control VIN=3.6V 0% -5% VIN=3.1V VIN=4.2V -15% 0 0 VIN=5.2V 5% -10% 0 0 VFB voltage variation 400 Duty[%] 6 8 10 -20% 0 Fig.17 LED brightness adjustment for PWM control (Expansion) 5/16 20 40 60 Duty[%] 80 100 Fig.18 LED brightness variation for PWM control (comparison of VFB at VIN=3.9V) 2011.12 - Rev.A Technical Note BD6077GUT ●Block diagram and pin configuration L 22µH CIN 1µF VIN SW VOUT over voltage protect Q2 short protect TSD Q1 Q S Q R PWMcomp Current Sence COUT 1µF + + VFB + RFB 24Ω OSC GND GNDA EN white LED ERRAMP + Control + - TEST Fig.19 Block diagram and recommended circuit diagram C1 C2 B3 B1 A1 C3 A2 A3 Fig.20 Pin location diagram VCSP60N1( 8 pin ) ●Pin assignment table PIN Name In/Out Ball number Function GNDA - A1 Analog GND EN In A2 Enable control (pull down by inner resistor) TEST In A3 TEST input (pull down by inner resistor) VIN In B1 Power supply input VFB In B3 Feedback voltage input VOUT Out C1 Boost output SW In C2 Switching terminal GND - C3 Power GND ●Operation BD6077GUT is PWM current mode DC/DC converter with fixed frequency. It adopts synchronous rectification architecture. The feature of the PWM current mode is that input is the combination of error components from the error amplifier, and a current sense signal that controls the inductor current into Slope waveform for sub harmonic oscillation prevention. This output controls Q1 and Q2 via the RS latch. Timing of Q1 and Q2 is precisely adjusted so that they will not turn ON at the same time, thus putting them into non-overlapped relation. In the period when Q1 is ON, energy is accumulated in the external inductor, and in the period when Q1 is OFF, energy is transferred to the capacitor of VOUT via Q2. Further more, BD6077GUT has many safety functions, and their detection signals stop switching operation at once. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 6/16 2011.12 - Rev.A Technical Note BD6077GUT ●Functional descriptions 1) Soft start and off status BD6077GUT has soft start function and off status function. The soft start function and the off status function prevent large current from flowing to the IC via coil. The soft start function prevents rush current when turning on and the off status function prevents invalid current when turning off. ・Soft start When VOUT is smaller than Vshort, to decrease charge current PMOS is set to off by PMOS Startup Control (in Term “I”). Vshort means “VOUT short detect voltage”. After VOUT is bigger than Vshort, PMOS is turned on and start switching. In term “II” (Vshort < VOUT < VIN), status of Current Limiter is “soft mode”. So “A” voltage is restricted and “D” duty is kept low. Therefore VOUT voltage goes up slowly and coil current is restricted. In term III (VOUT > VIN), status of Current Limiter is “normal mode”. So “A” voltage goes up suitable voltage, and “D” duty goes up slowly. And then VOUT voltage goes up to required voltage. Operation Current at start Current at PWM Max current 380mA 270mA LED VF=3.2V@20mA, COUT : 1µF@16V X5R Vout LED current L ERRAMP PWM comp SW A Soft Current limit B R Q S Q D C PMOS Startup Control Off Status Soft Reference Charge current OSC FB 24ohm Fig. 21 lock diagram of soft start and off status EN I II III VIN Vshort VOUT Normal mode Current Limit Soft mode D Fig. 22 timing chart ・Off status The gate voltage of the switching Tr either "H" or "L" at power off depends on the operation conditions at that time. When it is fixed to "H", the switching Tr remains to be ON, and invalid current from the battery is consumed. In order to prevent this, at power off, D is always fixed to L level. So that, it is possible to prevent invalid current at power off. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 7/16 2011.12 - Rev.A Technical Note BD6077GUT 2) Isolation control BD6077GUT has isolation control to prevent LED wrong lighting at power off. The cause of the LED wrong lighting is leak current from VIN to the white LED. Therefore, when BD6077GUT powered off (EN = L), the isolation control cuts the DC path between SW and Vout, so that, it prevents from leak current from VIN to LED. VIN SW White LED Vout VFB Fig.23 Isolation control 3) Short-circuit protection and over voltage protection BD6077GUT has short-circuit protection and over voltage protection. These detect the voltage of VOUT, and at error, they stop the output Tr. Details are as shown below. ・Short-circuit protection In the case of short-circuit of the DC/DC output (VOUT) to GND, the coil or the IC may be destroyed. Therefore, in a case of error as VOUT becomes 0.7V or lower, the Under Detector shown in the figure works, and turns off the output Tr, and prevents the coil and the IC from being destroyed. And the IC turns into non operation condition from operation condition, and current does not flow to the coil (0mA). ・Over voltage protection In a case of error as the IC and the LED being cut off, over voltage causes the SW terminal and the VOUT terminal exceed the absolute maximum ratings, and may destroy the IC. Therefore, when VOUT becomes 14.5V or higher, the over voltage limits works, and turns off the output Tr, and prevents the SW terminal and the VOUT terminal from exceeding the absolute maximum ratings. At this moment, turns into non operation condition from operation condition, and the output voltage goes down slowly. And, when the output voltage becomes the hysteresis of the over voltage limit or below, the output voltage goes on up to 14.5V once again. This protection action is shown in Fig.24. Cout SW Vout OVER Detector OVER VOLTAGE REF driver UNDER Detector UNDER VOLTAGE REF Control Fig.24 Block diagram of short-circuit protection and over voltage 4) Thermal shut down BD6077GUT has thermal shut down function. The thermal shut down works at 175°C or higher, and while holding the setting of EN control from the outside, turns into non operation condition from operation condition. And at 175°C or below, the IC gets back to its normal operation. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 8/16 2011.12 - Rev.A Technical Note BD6077GUT ●Start control and brightness control BD6077GUT can control the start conditions by its EN terminal, and power off at 0.4V or below, and power on at 1.4V or higher. And by changing the duty of power on and off by PWM control, the LED brightness can be adjusted. Two techniques are available for the brightness adjustment. One is PWM adjustment, and the other is analog adjustment. (1) PWM brightness adjustment is done by giving PWM signal to EN as shown in Fig.25. The BD6077GUT is powered on/off by the PWM signal. By this method, LED current is controlled from 0 to the maximum current. The average LED current increases with proportion to the duty cycle of PWM signal. While in PWM off-cycle mode, the IC and LED both consume no currents, thus providing a high-efficiency operation. The recommended PWM frequency is 100Hz ~ 300Hz. 22µH VIN SW VIN VOUT PWM 1µF EN TEST GNDA GND VFB 24Ω Fig.25 The brightness adjustment example of EN terminal by PWM (fPWM = 100 ~ 300Hz) High Pulse Minimum High Pulse = 26µs (Duty = 1/128) Range of Period = 3.3 ~ 10 ms EN Period Low Pulse Minimum Low Pulse = 26µs (Duty = 127/128) Range of Period = 3.3 ~ 10 ms EN Period Fig.26 The Rule of PWM signal of EN ●FB characteristic on PWM function BD6077GUT constantly controls the rising time to decrease the tolerance of the FB voltage at PWM function. EN PWM1 Pulse = 26µs (Duty = 1/128) (300Hz) 400 μ s typ VFB EN Fig.27 VFB signal at PWM Compare the value of VFB average voltage at VBAT=4.2V and at VBAT=3.9V in PWM1. (PWM1 = 1/128 Duty) Difference between VBAT=3.9V and 4.2V VFB voltage is less than 3%. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. VFB Average of This period time (VFB) Fig.28 VFB Line Regulation (PWM1) 9/16 2011.12 - Rev.A Technical Note BD6077GUT ●VBAT characteristic in Battery charge Transient during Battery charger is normally +300mV, 1Hz(duty 50%) from a baseline Battery Voltage 3.1 to 2.8V. In this term, it is necessary that VOUT Voltage noise is less than 200mVp-p. VBAT [V] 20µs VBAT [V] 20µs 4ms 3.1V 3.1V 2.8V 300mVp- p 2.8V 600µs time time VOUT [V] less than 200mVp -p time VFB[V] less than 100mVp -p time Fig.29 Battery Voltage transient during charger ●Setting range of LED current LED current is determined by the voltage of VFB and the resistor connected to VFB terminal. ILED is given as shown below. ILED=VFB/RFB The current in the standard application is as shown below. VFB=0.5V, RFB=24Ω ILED=20.8mA 22µH VIN 1µF SW VIN VOUT PWM EN 1µF ILED TEST GNDA GND VFB RFB 24Ω Fig.30 standard application www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 10/16 2011.12 - Rev.A Technical Note BD6077GUT ●Load Regulation Test The load current from VOUT is set as 15mA(LED)+10mA(key) and +10mA is set to ON/OFF and tested. At that time, VOUT and Ripple of VFB are measured. (VOUT : less than 700mV,VFB : less than 150mV) The difference of VFB voltage in case load is ON and the voltage at the time of being OFF is measured. (≤ ±1%) 22µH VIN 1µF SW VIN VOUT PWM EN less than 700mVp-p I load VOUT 1µF ILED TEST GNDA Less than 150mVp-p 1kΩ GND VFB VFB Aver.A RFB 33Ω 24Ω ON/OFF Aver.B I load 1 - A/B = less than 1% Fig.31 Load Regulation Test circuit Fig.32 Transient Load Regulation test The shaded portion in the figure below is the setting range of LED current to become the standard. Depending on coils and white LEDs to be used, however, some ICs may not be used at desired currents. Consequently, for the proper setting of LED current, thoroughly check it for the suitability under use conditions including applicable power supply voltage and temperature. 80 Po=310mW Line 70 ILED [mA] 60 50 40 30 20 10 0 7 8 9 10 11 12 13 14 VOUT [V] Fig.33 Setting range of LED current www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 11/16 2011.12 - Rev.A Technical Note BD6077GUT ●Selection of external parts Recommended external parts are listed as below. When to use other parts than these, select the following equivalent components. ・Coil Value Tolerance Manufacturer Product number Vertical size Size Horizontal size 22µH ±10% MURATA LQH32CN220K53 2.5 22µH ±20% MURATA LQH3NPN220MGOL 22µH ±20% Panasonic 22µH ±20% Taiyo Yuden Height DCR (Ω) 3.2 1.55 0.710 3.0 3.0 0.9 1.100 ELLVEG220NN 3.0 3.0 0.9 1.440 NR3010T220M 3.0 3.0 1.0 1.236 22µH ±20% TDK VLS3010T-220MR46 3.0 3.0 Please refer to the reference data of p.4 for the change in the efficiency when the coil is changed. 1.0 ・Capacitor Value Manufacturer Product number Vertical size Size Horizontal size MURATA GRM188B11A105K 1.6 MURATA GRM188R61C105K Height Temperature range 0.8 0.8 -25℃~+85℃ 1.6 0.8 0.8 -55℃~+85℃ [ CIN ] 1µF [ COUT ] 1µF ・Resistor Value Tolerance Manufacturer Product number Vertical size Size Horizontal size ±1% ROHM MCR006YZPF□□□□ 0.6 0.3 Height [ RFB ] 24Ω 0.23 Value □□□□ 15Ω 15R0 24Ω 24R0 33Ω 33R0 The coil is the component that is most influential to efficiency. Select the coil which direct current resistor (DCR) and current - inductance characteristic are excellent. The BD6077GUT are designed for the inductance value of 22µH. Please do not use other inductance value. Select a capacitor of ceramic type with excellent frequency and temperature characteristics. Further, select Capacitor to be used for CIN/COUT with small direct current resistance, and pay much attention to the PCB layout shown in the next page. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 12/16 2011.12 - Rev.A Technical Note BD6077GUT ●PCB layout In order to make the most of the performance of this IC, PCB layout is very important. Please note that characteristics such as efficiency and ripple will likely to change greatly depending on PCB layout. To battery power source CIN GNDA EN TEST VIN VFB VOUT SW RLED GND To battery GND COUT L1 Fig.34 PCB layout Connect the input bypath capacitor CIN between VIN and GNDA pin closely, as shown in the upper diagram. Thereby, the input voltage ripple of the IC can be reduced. And, connect the output capacitor COUT between VOUT and GND pin closely. Thereby, the output voltage ripple of the IC can be reduced. Connect the current setting RLED FB pin closely. Connect the GND closely connection side of RLED directly to GND pin. Connect the GNDA pin directly to GND pin. When those pins are not connected directly near the chip, the performance of BD6077GUT shall be influenced and may limit the current drive performance. As for the wire to the inductor, make its resistance component small to reduce electric power consumption and increase the entire efficiency. Please keep away which are subject to be influenced like FB pin in wire connection with SW. The layout pattern in consideration of these is shown in the next page. VOUT 83mV (VBAT=3.6V, Ta=25 oC, VOUT=10V. 34mA Load) Fig.35 Output noise www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 13/16 2011.12 - Rev.A Technical Note BD6077GUT ●Recommended PCB layout FB EN GNDA GND LED Cin RFB １ １V １ １V １ ２G LED Cout SW SW L1 VOUT LED VBAT １ ２G VOUT GND VOUT Fig.36 Front surface (TOP VIEW) VOUT Fig.37 Rear surface (TOP VIEW) ●Attention point for PCB layout For PCB layout design, the wire of power supply line should be low Impedance, and put bypass capacitor if necessary. Especially the wiring impedance must be low around DC/DC converter. ●About heat loss For heat design, operate DC/DC converter in the following condition. (The following temperature is a guaranteed temperature, margin will be needed.) 1. Periphery temperature Ta must be less than 85℃. 2. The loss of IC must be less than dissipation Pd. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 14/16 2011.12 - Rev.A Technical Note BD6077GUT ●Notes for use 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) Reverse connection of power supply connector The reverse connection of power supply connector can break down ICs. Take protective measures against the breakdown due to the reverse connection, such as mounting an external diode between the power supply and the IC’s power supply terminal. 4) 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. 5) 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. 6) 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. 7) Operation in strong electromagnetic field Be noted that using ICs in the strong electromagnetic field can malfunction them. 8) 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. 9) 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. 10) 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. 11) 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. 12) Thermal shutdown circuit (TSD) When junction temperatures become 175°C (typ) or higher, 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. 13) Thermal design Perform thermal design in which there are adequate margins by taking into account the permissible dissipation (Pd) in actual states of use. 14) Selection of coil Select the low DCR inductors to decrease power loss for DC/DC converter. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 15/16 2011.12 - Rev.A Technical Note BD6077GUT ●Ordering part number B D ROHM type name 6 0 7 Part No. 6077 7 G U T - Package GUT: VCSP60N1 E 2 Packaging and forming specification E2: Embossed tape and reel VCSP60N1 (BD6077GUT) <Tape and Reel information> Tape Embossed carrier tape Quantity 3000pcs Direction of feed (Unit:mm) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. E2 The direction is the 1pin of product is at the upper left when you hold ( reel on the left hand and you pull out the tape on the right hand 1pin Reel 16/16 ) Direction of feed ∗ Order quantity needs to be multiple of the minimum quantity. 2011.12 - Rev.A Notice Notes No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM Co.,Ltd. The content specified herein is subject to change for improvement without notice. The content specified herein is for the purpose of introducing ROHM's products (hereinafter "Products"). If you wish to use any such Product, please be sure to refer to the specifications, which can be obtained from ROHM upon request. Examples of application circuits, circuit constants and any other information contained herein illustrate the standard usage and operations of the Products. The peripheral conditions must be taken into account when designing circuits for mass production. Great care was taken in ensuring the accuracy of the information specified in this document. However, should you incur any damage arising from any inaccuracy or misprint of such information, ROHM shall bear no responsibility for such damage. The technical information specified herein is intended only to show the typical functions of and examples of application circuits for the Products. ROHM does not grant you, explicitly or implicitly, any license to use or exercise intellectual property or other rights held by ROHM and other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the use of such technical information. The Products specified in this document are intended to be used with general-use electronic equipment or devices (such as audio visual equipment, office-automation equipment, communication devices, electronic appliances and amusement devices). The Products specified in this document are not designed to be radiation tolerant. While ROHM always makes efforts to enhance the quality and reliability of its Products, a Product may fail or malfunction for a variety of reasons. Please be sure to implement in your equipment using the Products safety measures to guard against the possibility of physical injury, fire or any other damage caused in the event of the failure of any Product, such as derating, redundancy, fire control and fail-safe designs. ROHM shall bear no responsibility whatsoever for your use of any Product outside of the prescribed scope or not in accordance with the instruction manual. The Products are not designed or manufactured to be used with any equipment, device or system which requires an extremely high level of reliability the failure or malfunction of which may result in a direct threat to human life or create a risk of human injury (such as a medical instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuelcontroller or other safety device). ROHM shall bear no responsibility in any way for use of any of the Products for the above special purposes. If a Product is intended to be used for any such special purpose, please contact a ROHM sales representative before purchasing. If you intend to export or ship overseas any Product or technology specified herein that may be controlled under the Foreign Exchange and the Foreign Trade Law, you will be required to obtain a license or permit under the Law. Thank you for your accessing to ROHM product informations. More detail product informations and catalogs are available, please contact us. ROHM Customer Support System http://www.rohm.com/contact/ www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. R1120A