SI-8010GL Application Note Surface Molding Chopper Type Switching Regulator IC SI-8010GL October 2013 Rev.2.0 SANKEN ELECTRIC CO., LTD. SI-8010GL －－－ Contents －－－ 1. General Description 1-1 Features －－－－－－－－－－ 3 1-2 Applications －－－－－－－－－－ 3 1-3 Type －－－－－－－－－－ 3 2-1 Package Information －－－－－－－－－－ 4 2-2 Ratings －－－－－－－－－－ 5 2-3 Circuit Diagram －－－－－－－－－－ 7 3-1 PWM Output Voltage Control －－－－－－－－－－ 9 3-2 Overcurrent Protection / Thermal Shutdown －－－－－－－－－－ 10 4-1 External Components －－－－－－－－－－ 11 4-2 Pattern Design Notes －－－－－－－－－－ 15 4-3 Operation Waveform Check －－－－－－－－－－ 16 4-4 Thermal Design －－－－－－－－－－ 17 5-1 Soft Start －－－－－－－－－－ 19 5-2 Output ON / OFF Control －－－－－－－－－－ 19 5-3 Controllable Output Voltage －－－－－－－－－－ 19 5-4 Reverse Bias Protection －－－－－－－－－－ 20 6. Typical Characteristics －－－－－－－－－－ 21 7. Terminology －－－－－－－－－－ 22 2. Specification 3. Operational Description 4. Cautions 5. Applications 2 SI-8010GL 1. General Description The SI-8010GL is a chopper type switching regulator IC which is provided with various functions required for the buck switching regulator and protection functions. A high speed, high precision and high efficiency switching regulator of 250 KHz operating frequency can be composed. The package unifying the GND pin of IC and the inner frame is used to reduce thermal resistance significantly. ● 1-1 Features - Compact size and large output current of 3A The maximum output current of 1.5A for the outline of DIP8 - High efficiency of 86% (VIN = 20V / Vo / Io = 5V / 1A) As the DMOS is used in the output stage, heat generation can be reduced and heat dissipation pattern can be made smaller. - Reference oscillation by a built-in timing capacitor No external capacitor for setting the oscillation frequency is required. - Built-in functions for overcurrent and thermal shutdown The foldback type overcurrent protection and thermal shutdown circuit are built in. (Automatic recovery type) - Soft start function (capable of ON/OFF output) By adding an external capacitor, it is possible to delay the rise speed of the output voltage. ON/OFF control of the output is also possible. - The output voltage can be adjusted by an external resistor. By using 2 pieces of external resistors, the output voltage is variable in the range of +1V to + 14V. ● 1-2 Applications For on-board local power supplies, power supplies for OA equipment, stabilization of secondary output voltage of regulator and power supply for communication equipment ● 1-3 Type - Type: Semiconductor integrated circuits (monolithic IC) - Structure: Resin molding type (transfer molding) 3 SI-8010GL 2. Specification ● 2-1 Package Information VREF Comp BS 8 7 6 a SK VIN 5 8010GL b c c a 8010GL 1 2 3 4 GND CE/SS Reg SWout a. Type number b. Lot number (three digit) 1st letter The last digit of year 2nd letter Month 1 to 9 for Jan. to Sept., O for Oct. N for Nov. D for Dec. 3rd letter Assembly span 1-3: Arabic Numerical c. Control number (four digit) c 4 SI-8010GL ● 2-2 Ratings Table 1 Absolute Maximum Rating Parameter Symbol Rating Unit VIN 53 V Allowable Power Dissipation Pd 1 W Junction Temperature Tj 125 °C Storage Temperature Tstg -40 - 125 °C Input Voltage Thermal Resistance (Junction and case) Thermal Resistance (Junction and ambient) θj-c 28 °C /W θj-a 100 °C /W Condition Glass epoxy board: 7000mm2 (Copper foil area in package: 3080mm2) Glass epoxy board: 7000mm2 (Copper foil area in package: 3080mm2) Glass epoxy board: 7000mm2 (Copper foil area in package: 3080mm2) Table 2 Recommended conditions Ratings Parameter Symbol Unit MIN MAX Input Voltage VCC 8 or VO+3 50 V Output Voltage Vo 1 14 V Output Current *1 IOUT 0.02 1.5 A Junction Temperature in Operation Tjop -30 125 °C Operation Temperature Top -30 85 °C Conditions *1: It is strongly recommended to apply over 20mA on output current. It may cause unstable output voltage if output current is less than 20mA. 5 SI-8010GL Table 3 Electrical Characteristics (Ta = 25°C) Ratings Parameter Setting Reference Voltage Output Voltage Temperature Symbol VREF Unit MIN TYP MAX 0.97 1.00 1.03 V Conditions VIN = 12V，IO = 1A ⊿VREF/⊿T ±0.5 mV/°C Efficiency Eff 86 % Operation Frequency fosc 250 kHz VIN = 12V, IO = 1A Line Regulation VLine 20 40 mV VIN = 10 - 30V, IO = 1A Load Regulation VLoad 10 30 mV Coefficient Overcurrent Protection Start Current Circuit Current in Non-operation 1 Circuit Current in Non-operation 2 Low Level Voltage IS Iq 1.6 A 7 mA Iq(off) 400 μA VSSL 0.5 V ISSL 50 μA VIN = 20V, IO = 1A, VO = 5V VIN = 12V, IO = 0.1 - 1.5A VIN = 12V VIN = 12V, IO = 0A VIN = 12V VON/OFF = 0.3V CE/SS terminal Flow-out Current at Low Level VSSL = 0V Voltage 6 SI-8010GL ● 2-3 Circuit Diagram 2-3-1 Internal Equivalent Circuit VIN SI-8010GL 11 C1 ５ VIN UVLO 4 ２ P.REG OCP CE/SS CE/ SS C4 Boot REG TSD BS ６ 12 R1 DRIVE 5 ３ Reg C3 ４ PWM LOGIC OSC 7 L1 D1 VREF Comp ８ Amp 1V C6 AGND DGND １ １ 1 C8 C2 R2 ７ VOUT SWOUT C5 14 C7 C9 15 R3 3 2-3-2 Typical Connection Diagram 6 B.S 5 VIN 2 C1 C7 C4 GND R1 C3 VIN SI-8010GL SWOUT VO 4 D1 R2 CE/SS Reg Comp 3 7 C5 L1 GND 1 C9 VREF C2 8 R3 C8 IR EF C6 GND C1: 220μF / 63V C2: 470μF / 25V C3: 0.1μF C4: 1000pF C5: 0.1μF C6: 0.047μF C7: 0.1μF C8: 0.1μF C9: 6800pF R1: 47Ω L1: 47μH D1: RK16 7 SI-8010GL 2-3-3 Main Components List Component Spec Recommended materials C1 220μF / 63V / Electrolytic capacitor EMVY630GTR221MLHoS (Nippon Chemi-Con) C2 470μF / 25V / Electrolytic capacitor UUD1E471MNR1GS (nichicon) C3, C5 0.1μF / 10V / Ceramic capacitor GRM31BR11A105MA01B (MURATA) C4 0.1μF / 50V / Ceramic capacitor GRM21BR11H104MA01B (MURATA) C6 0.1μF / 50V / Ceramic capacitor GRM21BR11H104MA01B (MURATA) C7, C8 0.1μF / 50V / Ceramic capacitor GRM21BR11H104MA01B (MURATA) C9 0.1μF / 50V / Ceramic capacitor GRM21BR11H104MA01B (MURATA) L1 47μH / Inductor SLF12575T-470M2R7 (TDK) D1, D2 1.5A / 60V / Schottky barrier diode RK16 (Sanken) R1 47Ω - R2 2kΩ (VO = 5V) - R3 500Ω - 8 SI-8010GL 3. Operational Description ● 3-1 PWM Output Voltage Control In the SI-8010GL series, the output voltage is controlled by the PWM system and the IC incorporates the PWM comparator, oscillator, error amplifier, reference voltage, output transistor drive circuit etc. The triangular wave output (≈ 250KHz) from the oscillator and the output of the error amplifier are given to the input of the PWM comparator. The PWM comparator compares the oscillator output with the error amplifier output to turn on the switching transistor for a time period when the output of the error amplifier exceeds the oscillator output. PWM Control Chopper Type Regulator Basic Configuration VOUT Switching Transistor ｽｲｯﾁﾝｸﾞﾄﾗﾝｼﾞｽﾀ VIN PWM Comparator ＰＷＭｺﾝﾊﾟﾚｰﾀ D1 C2 Drive Circuit ドライブ回路 Error Amplifier 誤差増幅器 Oscillator 発振器 Reference 基準電圧 Voltage The error amplifier output and the oscillator output are compared by the PWM comparator to generate the drive signal of rectangular wave and to drive the switching transistor. On the assumption that the output voltage attempts to rise, the output of the error amplifier is lowered, because the error amplifier is of inverting type. When the output of the error amplifier is lowered, the time period where it exceeds the triangular wave of the oscillator is decreased to shorten the ON time of the switching transistor and as a result, the output voltage is maintained constant. As described above, the output voltage is controlled by varying the ON time of the switching transistor with the switching frequency fixed (the higher is VIN, the shorter is the ON time of the switching transistor.) PWM Comparator Operation Diagram Oscillator 発振器出力 Output Error Amplifier 誤差増幅器出力 ON OFF Output ｽｲｯﾁﾝｸﾞﾄﾗﾝｼﾞｽﾀ出力 Switching Transistor Output 9 SI-8010GL The rectangular wave output of the switching transistor is smoothed by the LC low pass filter composed of a choke coil and a capacitor to supply stabilized DC voltage to the load. ● 3-2 Overcurrent Protection / Thermal Shutdown The SI-8010GL includes the foldback type overcurrent protection circuit. The overcurrent protection circuit detects the peak current of a switching transistor and when the peak current exceeds the set value, the ON time of the transistor is compulsorily shortened to limit the current by lowering the output voltage. When the overcurrent condition is released, the output voltage will be automatically restored. Output Voltage Characteristic on Overcurrent 出力電圧 Output Voltage Output出力電流 Current The thermal shutdown circuit detects the semiconductor junction temperature of the IC and when the junction temperature exceeds the set value, the output transistor is stopped and the output is turned OFF. When the junction temperature drops from the set value for overheat protection by around 15°C, the output transistor is automatically restored. * Note for thermal shutdown characteristic This circuit protects the IC against overheat resulting from the instantaneous short circuit, but it should be noted that this function does not assure the operation including reliability in the state that overheat continues due to long time short circuit. Output Voltage Characteristic on Thermal Shutdown 出力電圧 Output Voltage Restoration setting Temperature 復帰設定温度 Protection Setting Temperature 保護設定温度 接合温度 Junction Temperature 10 SI-8010GL 4. Cautions ● 4-1 External Components 4-1-1 Choke coil L The choke coil L1 plays a main role in the chopper type switching regulator. In order to maintain the stable operation of the regulator, such dangerous state of operation as saturation state and operation at high temperature due to heat generation must be avoided. The following points should be taken into consideration for the selection of the choke coil. a) The choke coil should be fit for the switching regulator. The coil for a noise filter should not be used because of large loss and generated heat. b) The inductance value should be appropriate. The larger is the inductance of the choke coil, the less is the ripple current flowing across the choke coil, and the output ripple voltage drops and as a result, the overall size of the coil becomes larger. On the other hand, if the inductance is small, the peak current flowing across the switching transistor and diode is increased to make the ripple voltage higher and this operation state is not favorable for maintaining the stable operation. Large Inductance Small Ripple Voltage/ Current The larger is the inductance, the smaller will be the ripple current/voltage. But the outer size of the coil becomes larger. Small Inductance Large Ripple Voltage/ Current The smaller is the inductance, the larger will be the ripple curtent/voltage. Although the outer size of the coil is smaller, the operation is likely to be unstable. The inductance value shown in the specifications should be considered as a reference value for the stable operation and the appropriate inductance value can be obtained by the following equation. ΔIL shows the ripple current value of the choke coil and the lower limit of inductance is set as described in the following. - In the case that the output current to be used is nearly equal to the maximum rating (1.5A) of the SI-8010GL: output current × 0.2- 0.3 - In the case that the output current to be used is approximately 1A or less: output current × 0.5 - 0.6 L (Vin Vout ) Vout IL Vin f －－－(1) 11 SI-8010GL For example, where VIN = 25V, VOut = 5V, ΔIL = 0.35A, frequency = 250kHz, L1 (25 5) 5 ≒ 45.7uH 0.35 25 250 10 3 As shown above, the coil of about 47μH may be selected. c) The rated current shall be met. The rated current of the choke coil must be higher than the maximum load current to be used. When the load current exceeds the rated current of the coil, the inductance is sharply decreased to the extent that it causes saturation state at last. Please note that overcurrent may flow since the high frequency impedance becomes low. d) Noise shall be low. In the open magnetic circuit core which is of drum shape, since magnetic flux passes outside the coil, the peripheral circuit may be damaged by noise. It is recommended to use the toroidal type, EI type or EE type coil which has a closed magnetic circuit type core as much as possible. 4-1-2 Input Capacitor C1 The input capacitor is operated as a bypass capacitor of the input circuit to supply steep current to the regulator during switching and to compensate the voltage drop of the input side. Therefore, the input capacitor should be placed as close as to the regulator IC. In addition, in the case that the smoothing capacitor of the AC rectifier circuit is located in the input circuit, the input capacitor may be also used as a smoothing capacitor, but similar attention should be paid. The selection of C1 shall be made in consideration of the following points: a) The requirement of withstand voltage shall be met. b) The requirement of the allowable ripple voltage shall be met. Current Flow of C1 Current Waveform of C1 C1電流波形 IIN VIN 5. V 1.V ININ Ripple Current ﾘｯﾌﾟﾙ電流 0 Iv Ip C1 D Ton Ton T T The ripple current of the input capacitor is increased in accordance with the increase of the load current. 12 SI-8010GL If the withstanding voltages or allowable ripple voltages are exceeded or used without derating, it is in danger of causing not only the decreasing the capacitor lifetime (burst, capacitance decrease, equivalent impedance increase, etc) but also the abnormal oscillations of regulator. Therefore, the selection with sufficient margin is needed. The effective value of ripple current flowing across the input capacitor can be obtained by the following equation: Irms 1.2 Vo Iout Vin －－(2) For instance, where Io = 3A, VIN = 20V, Vo = 5V, Irms 1.2 5 3 0.9 A 20 Therefore, it is necessary to select the capacitor with the allowable ripple current of 0.45A or higher. 4-1-3 Output Capacitor C2 The output capacitor C2 composes a LC low pass filter together with a choke coil L1 and functions as a rectifying capacitor of switching output. The current equivalent to the pulse current ΔIL of the choke coil current is charged and discharged in the output capacitor. Therefore, it is necessary to meet the requirements of withstand voltage and allowable ripple current with sufficient margin like the input capacitor. The following points should be taken into consideration. Current Flow of C2 IL Vout L1 Current Waveform of C2 ﾘｯﾌﾟﾙ電流 ESR C2電流波形 Io Ripple Current 0 RL ⊿IL The ripple current of the output capacitor is equal to the ripple current of the choke coil and does not vary even if the load current increases or decreases. C2 a) Allowable Ripple Current The ripple current effective value of the output capacitor is obtained by the equation. Irms IL 2 3 －－－(3) When ΔIL = 0.5A, Irms 0.5 ≒ 014 . A 2 3 Therefore a capacitor having the allowable ripple current of 0.14A or higher is required. The output ripple voltage is determined by a product of the pulse current ΔIL (=C2 discharge and charge current) 13 SI-8010GL of the choke coil current and the ESR Vrip IL C2ESR －－－(4) b) DC equivalent series resistance (ESR) It is necessary for the stable operation to select the ESR properly. When the ESR is too large or too small, abnormal oscillation due to increase of ripple voltage or insufficient phase margin occurs respectively. The output ripple voltage is determined by a product of the pulse current ΔIL (=C2 discharge and charge current) of the choke coil current and the ESR, and the output ripple voltage which is 0.5 - 1% of the output voltage (for example, 25mV where 0.5% at VOUT = 5V.) is good for the stable operation. Please refer to the equations (4) and (5) to obtain the output ripple voltage. It should be noted that the ESR is changeable subject to temperature and it is especially lowered at high temperature. Vrip Vin Vout Vout ESR －－－(5) L Vin f Vrip IL ESR －－－(6) However, if the ESR of the output capacitor is too low (10 - 20mΩ or lower), the phase margin within the feedback loop of the regulator will be short to make the operation unstable. Therefore, it is not appropriate that a tantalum capacitor or a laminated ceramic capacitor is used for the output capacitor as an independent component. However, connecting a tantalum capacitor or a laminated ceramic capacitor in parallel with an electrolytic capacitor is effective in reducing the output ripple voltage only when it is used at low temperature (< 0°C). In addition, in order to further decrease the ripple voltage, as shown below, it is also effective to add one stage of the LC filter to form the π type filter. L1 L2 4.SWOUT 5.VIN SI-8010GL 1,GND L2: 20μH 8.VREF D1 C2 C4 C4: 200μF The abnormal oscillation can be caused unless the output voltage detection point (wiring to the Vos terminal) is placed before the second stage filter if the second stage filter is added. Therefore, the care should be taken. It should be noted that the operating stability is more influenced by the ESR than the capacitance as described above if the requirements of withstand voltage and allowable ripple current are met. 4-1-4 Flywheel Diode D1 The flywheel diode D1 is to discharge the energy which is stored in the choke coil at switching OFF. For the flywheel diode, the Schottky barrier diode must be used. If a general rectifying diode or fast recovery diode is used, the IC may be destroyed by applying reverse voltage due to the recovery and ON voltage. In addition, since the 14 SI-8010GL output voltage from the SWOUT terminal (pin 4) of the SI-8010GL series is almost equivalent to the input voltage, the flywheel diode with the reverse withstand voltage of the input voltage × 1.2 or higher should be used. ● 4-2 Pattern Design Notes 4-2-1 High Current Line Since high current flows in the bold lines in the connection diagram, the pattern should be as wide and short as possible. 5 VIN 11,VIN 7.SWOUT L1 4 VOUT SI-8010GL SPI-8010A C1 4.SS 1,3.GND 1 15.VOS 8 D1 GND C2 GND 4-2-2 Input / Output Capacitor The input capacitor C1 and the output capacitor C2 should be placed to the IC as close as possible. If the rectifying capacitor for AC rectifier circuit is on the input side, it can be used as an input capacitor. However, if it is not close to the IC, the input capacitor should be connected in addition to the rectifying capacitor. Since high current is discharged and charged through the leads of input/output capacitor at high speed, the leads should be as short as possible. A similar care should be taken for the patterning of the capacitor. C1,C2 Improper Pattern Example C1,C2 Proper Pattern Example 4-2-3 Sensing Terminal The output voltage sensing terminal Vos shall be connected near the output capacitor C2 as much as possible. If it is connected far from C2, it should be noted that abnormal oscillation may happen due to the low regulation and increased switching ripple. 15 SI-8010GL ● 4-3 Operation Waveform Check It can be checked by the waveform between the pin 1 and 4 (SWOUT - GND waveform) of the SI-8010GL whether the switching operation is normal or not. The examples of waveforms at normal and abnormal operations are shown below: 1. Normal Operation (continuous area) 2. Normal Operation (discontinuous area) 3. When C1 is far from IC 4. When C2 is far from IC The continuous area is an area where the DC component of the triangular wave is superimposed on the current flowing across the choke coil and the discontinuous area is an area where the current flowing across the choke coil is intermittent (a period of zero current may happen.) because the current flowing across the choke coil is low. Therefore, when the load current is high, the area is a continuous area and when the same current is low, the area is a discontinuous area. In the continuous area, the switching waveform is formed in the normal rectangular waveform (waveform 1) and in the discontinuous area, damped oscillation is caused in the switching waveform (waveform 2), but this is a normal operation without any problem. In the meantime, when the IC is far from C1 and C2, jitter which disturbs the ON - OFF time of switching will happen as shown in the waveforms (3, 4). As described above, C1 and C2 should be connected close to the IC. 16 SI-8010GL ● 4-4 Thermal Design 4-4-1 Calculation of Heat Dissipation The relation among the power dissipation Pd of regulator, junction temperature Tj, case temperature Tc, board temperature Tfin and ambient temperature Ta is as follows: Pd (Power dissipation) Pd(損失) Tj: Temperature (125°C max) Tj Junction ｼﾞｬﾝｸｼｮﾝ温度(125℃MAX) チップ Chip Θjc: Thermal Resistance (Junction – Case) 5.5°C / W θ jc(接合－ｹｰｽ間熱抵抗) 5.5℃/W ケース Case Tc: temperature (internal frame temperature) Tc Case ｹｰｽ温度(内部ﾌﾚｰﾑ温度) Board 基板 Θi: Thermal Resistance (Case - Heat sink) 0.4 – 0.6°C / W θ i(ｹｰｽ－放熱器間熱抵抗) 0.4～0.6℃/W Tfin 放熱器温度 Tfin: Board temperature Θfin: Board Thermal resistance θ fin(基板熱抵抗) Ta Ambient 周囲温度temperature Ta: Tj Tc －－(7) jc Tj Tfin －－(8) Pd jc i Tj Ta －－(9) Pd jc i fin Pd The TjMAX is an inherent value for each product, therefore it must be strictly observed. For this purpose, it is required to design the board pattern in compliance with PdMAX, TaMAX (determination of θfin). The heat derating graphically describes this relation. The designing of the heat sink is carried out by the following procedure: 1) The maximum ambient temperature Ta MAX in the set is obtained. 2) The maximum power dissipation PdMAX is obtained. 100 Vo Pd Vo Io 1 Vf Io1 Vin x －－－(10) * ηx= efficiency (%), Vf= diode forward voltage 3) The size of heat sink is determined from the intersection of the heat derating. The required thermal resistance of the heat sink can be also calculated. The thermal resistance required for the heat sink is obtained by the following equation: 17 SI-8010GL i fin Tj Ta jc Pd －－－(11) An example of heat calculation for using SI-8010GL under the conditions of VIN = 10V, VOUT = 5V, IOUT = 1.5A and Ta = 85°C is shown below. Where efficiency η = 87% , Vf = 0.5V from the typical characteristics, 5 100 Pd 5 1.5 1 0.5 1.5 1 ≒ 0.75W 87 10 125 85 i fin 28 ≒ 25.33ﾟC / W 0.75 As a result, the heat sink with the thermal resistance of 25°C /W or less is required. As described above, the thermal resistance of board is determined, but the derating of 10 - 20% or more is used. Actually, heat dissipation effect significantly changes depending on the difference in component mounting. Therefore, board temperature or case temperature at mounted should be checked. 4-4-2 Installation to Board GND pattern The SI-8010GL adopts a package which unifies the GND terminal (No.1 pin) and a frame in the IC. In order to enhance the heat dissipation effect, it is recommended to make the GND pattern wide. 18 SI-8010GL 5. Applications ● 5-1 Soft Start When a capacitor is connected to No.2 terminal of the SI-8010GL, soft start operation can be made for the purpose of providing delay time from the application of input voltage to the rise of output voltage. By means of this operation, the state of high input voltage is realized prior to the operation of a regulator. In the case of the buck converter type switching regulator, as the input voltage becomes higher the input current is reduced, therefore the operation can be started with less current. In the case of the actual equipment, more or less variation takes place because of the influence from the rise time of input power supply. The C4 should be used with 4700 pF or less. SI-8010GL Vin 2 Td Vo C4 3.2 C 4 ( Sec ) 15 10 6 Td ● 5-2 Output ON / OFF Control The output ON-Off control is possible using the soft start (No.5) terminal. The output is turned OFF when the terminal 5 voltage falls to low by such as open collector. It is possible to use the soft start together. Since the soft start terminal has been already pulled up, no voltage shall be applied from the external side. SI-8010GL 2.CE/SS C3 CE/SS + ON/OFF ● 5-3 Controllable Output Voltage R2 and R3 are resistors for setting the output voltage. It should be set in a manner that IREF is around 2mA. The equation by which the values of R2 and R3 can be obtained is as follows: V VREF VOUT 1 ，R3 VREF 1 ≒ 500 R2 OUT I REF 2 103 I REF 2 103 19 SI-8010GL ● 5-4 Reverse Bias Protection A diode for reverse bias protection is required between input and output when the output voltage is higher than the input terminal voltage, such as in battery chargers. SI-8010GL 20 SI-8010GL 6. Typical Characteristics Efficiency Characteristic of Overcurrent Vo=14V 1.2 Io=1.5A 1A 90 Vo=5V 0.5A Io=1.5A 80 1A 0.5A 70 Vo=1.8V Io=1.5A 1A 60 VIN=30V 20V 12V 8V 1.0 Output Voltage VO [V] Efficiencyη [%] 100 0.8 0.6 0.4 0.2 0.5A 50 0 50 10 20 30 0 40 1 2 3 4 Output Current Io [A] Input Voltage VIN [V] Output Voltage Rising *Load = C.R 1.2 IO=0.02A Thermal Shutdown Protection VIN=12V, 1.2 1.0 1.0 Output Voltage VO [V] Output Voltage VO [V] 0 0.8 IO=0.02A 1A 1.5A 0.6 0.4 0.2 0.8 0.6 TSD OFF 0.4 TSD ON 0.2 0 0 5 10 15 Input Voltage VIN [V] 20 50 Load Regulation Characteristics Efficiency η [%] 1.01 VIN=8V 12V Operating Frequency [kHz] Output Voltage VO [V] 1.02 1.00 20V 30V 0.99 0.98 0.5 Output Current IO [A] 200 Temperature Characteristics VIN=12V, IO=1A 300 1.03 0.97 0 1.5 Ambient Temperature150 Ta [°C] 100 1.0 1.015 Freq 250 1.01 200 1.005 VO 150 100 1 0.995 Output Voltage VO [V] 0 η 50 0.99 -50 0 50 100 Ambient Temperature Ta [°C] 150 21 SI-8010GL 7. Terminology - Jitter It is a kind of abnormal switching operations and is a phenomenon that the switching pulse width varies in spite of the constant condition of input and output. The output ripple voltage peak width is increased when a jitter occurs. - Recommended Conditions It shows the operation conditions required for maintaining normal circuit functions. It is required to meet the conditions in actual operations. - Absolute Maximum Ratings It shows the destruction limits. It is required to take care so that even one item does not exceed the pacified value for a moment during instantaneous or normal operation. - Electrical Characteristics It is the specified characteristic value in the operation under the conditions shown in each item. If the operating conditions are different, it may be out of the specifications. - PWM (Pulse Width Modulation) It is a kind of pulse modulation systems. The modulation is achieved by changing the pulse width in accordance with the variation of modulation signal waveform (the output voltage for chopper type switching regulator). - ESR (Equivalent Series Resistance) It is the equivalent series resistance of a capacitor. It acts in a similar manner to the resistor series-connected to the capacitor. 22 SI-8010GL Notice ・The contents of this description are subject to change without prior notice for improvement etc. Please make sure that any information to be used is the latest one. ・Any example of operation or circuitry described in this application note is only for reference, and we are not liable to any infringement of industrial property rights, intellectual property rights or any other rights owned by third parties resulting from such examples. ・In the event that you use any product described here in combination with other products, please review the feasibility of combination at your responsibility. ・Although we endeavor to improve the quality and reliability of our product, in the case of semi-conductor components, defects or failures which occur at a certain rate of probability are inevitable. The user should take into adequate consideration the safety design in the equipment or the system in order to prevent accidents causing death or injury, fires, social harms etc.. ・Products described here are designed to be used in the general-purpose electronic equipment (home appliances, office equipment, communication terminals, measuring equipment etc.). If used in the equipment or system requiring super-high reliability (transport machinery and its control equipment, traffic signal control equipment, disaster/crime prevention system, various safety apparatus etc.), please consult with our sales office. Please do not use our product for the equipment requiring ultrahigh reliability (aerospace equipment, atomic control, medical equipment for life support etc.) without our written consent. ・The products described here are not of radiation proof type. ・The contents of this brochure shall not be transcribed nor copied without our written consent. 23