SI-3010LLSL Application Note Super Hyposaturation type Series Regulator IC SI-3010LLSL Series August 2011 Rev.2.1 SANKEN ELECTRIC CO., LTD. SI-3010LLSL －－－ Contents －－－ 1. General Description 1-1 Features －－－－－－－－－－ 3 1-2 Application －－－－－－－－－－ 3 1-3 Type －－－－－－－－－－ 3 2-1 Package Information －－－－－－－－－－ 4 2-2 Ratings －－－－－－－－－－ 5 2-3 Circuit Diagram －－－－－－－－－－ 6 3-1 Voltage Control －－－－－－－－－－ 7 3-2 Overcurrent Protection －－－－－－－－－－ 7 3-3 Thermal Shutdown －－－－－－－－－－ 8 4-1 External Components －－－－－－－－－－ 9 4-2 Pattern Design Notes －－－－－－－－－－ 9 5-1 Output ON / OFF Control －－－－－－－－－－ 10 5-2 Thermal Design －－－－－－－－－－ 10 －－－－－－－－－－ 11 2. Specification 3. Operational Description 4. Cautions 5. Applications 6. Typical Characteristics 2 SI-3010LLSL 1. General Information The SI-3010LLSL is a series regulator IC using NPN bipolar transistors for a power section. The VIN terminal is connected to the NPN bipolar transistor of a power section. The VB terminal is connected to the power supply of the control section and also to the former stage transistor in Darlington connection with the NPN power transistor connected to the VIN terminal. By performing 2 inputs, the SI-3010LLSL is operated in the ultra hyposaturation to the VIN terminal. The ON/OFF terminal of “Active High” is provided to make the current consumption of circuits at OFF time zero. This is a regulator that uses low ESR capacitors like a ceramic capacitor for the output capacitor. ● 1-1 Features - Output current 1.5A Output current is 1.5A at maximum with the outline of SOP8. - Hyposaturation (Vdif = 0.3Vmax / Io = 1A) It can be designed with super low difference of input/output voltages. - ON/OFF function The ON/OFF terminal which can be directly controlled by TLL logic signals is provided. - Low current consumption Current consumption of circuits at OFF time is zero. Dark currents at no load are 500μA at maximum. - Built-in Overcurrent protection / Thermal shutdown The current limiting type overcurrent protection and Thermal shutdown circuits are built-in. (Automatic restoration type) ● 1-2 Application 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-3010LLSL 2. Specification Unit: mm ● 2-1 Package Information Pin assignment 1. Vo 2. ADJ 3. VB 4. Vc 5. GND 6. GND 7. VIN 8. VIN 4 SI-3010LLSL ● 2-2 Ratings 2-2-1 Absolute Maximum Ratings Ta = 25°C *1: When mounted on glass-epoxy board of 40 × 40mm (copper laminate area 100%). 2-2-2 Recommended Conditions *1: Because of the relation of Pd = (Vin - Vo) × Io, Vin (max.) and Io (max.) may be restricted subject to conditions of use. For each value, refer to the data of copper foil area - permissible loss for calculation. 2-2-3 Electrical Characteristics Ta = 25°C, Vc = 2V, VIN = 1.8V, VB = 3.3V and VO = 1.5V without special instruction *1: Is1 is specified at the 5% drop point of output voltage Vo on the condition that VIN = overcurrent protection starting current, Io = 10mA. *2: Output is OFF when the output control terminal (Vc terminal) is open. Each input level is equivalent to LS-TTL level. Therefore, the device can be driven directly by LS-TTLs. 5 SI-3010LLSL ● 2-3 Circuit Diagram 2-3-1 Block Diagram CIN, CB: Input Capacitor and Biased Capacitor (0.1μF - 10μF) It is required in the case of that input line includes inductance or it has long line. Co: Output capacitors (47μF or more) The SI-3010LLS is designed on the assumption that low ESR type capacitors such as ceramic capacitors are used for the output capacitor. It is recommended to use capacitors with the ESR of 500mΩ or less (at room temperature) for the output capacitor. R1, R2: resistors for setting output voltages Output voltages can be adjusted by connecting R1 and R2 as shown in the above figure. R2: 10kΩ is recommended. R1=(Vo-VADJ) /（VADJ /R2） CSS = Capacitors for soft start setting It is possible to set the rise time of output voltage by connecting CSS between VOUT and ADJ. *Around 0. 3A is required for the current capacity of VB power supply. 2-3-2 Application circuit 6 SI-3010LLSL 3. Operational Description ● 3-1 Voltage Control In the SI-3010LLSL series, the driving circuit is controlled by comparing the reference voltage with the ADJ terminal voltage (voltage divided by Vo detection resistor in fixed output products) to stabilize the output voltage by varying the voltage between the emitter and collector of a main NPN power transistor. The product of voltage between collector and emitter and the output current at this moment is consumed as heat. In the SI-3010LLSL, a NPN transistor connected to the VIN terminal and a PNP transistor connected to the VB terminal are in Darlington connection and are operated at hyposaturation to the VIN terminal. Although the VIN terminal input voltage is 1.3V at minimum (MIN), it is required to apply 3.0V or higher to the VB terminal for the stable operation of control section. In order to operate the main power transistor for Darlington operation, it is required for VB terminal to apply the VB voltage which is higher by 1.2V or more than VIN voltage. ● 3-2 Overcurrent Protection The current limiting type overcurrent protection function is provided in the SI-3010LLSL. In the case of the series regulator, as the output voltage drops subject to the overcurrent protection, the difference of input/output voltages increases to cause significant heating. Special care should be taken for the current limiting type overcurrent protection, since large current flows continuously. Output Voltage VO (V) <Example of foldback type overcurrent protection characteristic> Output Current IO (A) 7 SI-3010LLSL ● 3-3 Thermal Shutdown This IC is provided with the overheat protection circuit which detects the semiconductor junction temperature of the IC to limit the driving current, when the junction temperature exceeds the set value (around 150°C). Since the minimum operating temperature of the overheat protection circuit is 130°C, the thermal design of Tj < 125°C is required. Hysteresis is provided for overheat protection, therefore when the junction temperature falls down to around 40℃, automatic restoration takes place. Restoration also takes place, when the input voltage is interrupted or operation is restarted at VC terminal. Output voltage <ex. Thermal Shutdown> About 40°C About 150°C Output current *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. 8 SI-3010LLSL 4. Cautions ● 4-1 External Components 4-1-1 Input Capacitor CIN The input capacitor is required to eliminate noise and stabilize the operation and values of 0.1μF - 10μF are recommended. Any of ceramic capacitors or electrolytic ones may be used for the input capacitor. 4-1-2 Output Capacitor Co In the output capacitor Co, larger capacitance than the recommended value is required for phase compensation. Equivalent series resistance values (ESR) of capacitors are limited, and depending on products, therefore the type of recommended capacitors is limited. - Recommendation: ESR < 500mΩ It is recommended to use ceramic capacitors or functional polymer capacitors. If electrolytic capacitors having large ESR are used, the phase margin is decreased to cause the possible oscillation of output voltage. Even if oscillation does not occur at low temperature, ESR is increased to cause oscillation, therefore the use of electrolytic capacitors is not recommendable. ● 4-2 Pattern Design Notes 4-2-1 Input / Output Capacitor The input capacitor C1 and the output capacitor C2 should be connected 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 no close to the IC, the input capacitor should be connected in addition to the rectifying capacitor. 4-2-2 ADJ Terminal (Output Voltage Set-up for SI-3010LLSL) The ADJ terminal is a feedback detection terminal for controlling the output voltage. The output voltage set-up is achieved by connecting R1 and R2. SI-3010LLSL: it should be set in a manner that IADJ is around 100μA. R1, R2 and output voltage can be obtained by the following equations: IADJ=VADJ/R2 *VADJ = 1.00V ± 2% (SI-3010LLSL, R2 = 10kΩ recommended R1 = (Vo-VADJ) / IADJ R2 = VADJ / IADJ Vout = R1× (VADJ / R2) + VADJ 9 SI-3010LLSL 5. Applications ● 5-1 Output ON/OFF Control The ON/OFF control of output can be made by directly applying voltage to No.4 Vc terminal. When the Vc terminal is open, the operation is in OFF. The Vc terminal is in OFF below 0.8V and in ON at above 2V. ● 5-2 Thermal Design Calculation of heat dissipation Heat generation of the surface mounting IC is generally dependent on size, material and copper foil area of the mounted printed circuit board. Full attention should be paid to heat dissipation and adequate margin be taken into consideration at thermal design. In order to enhance the heat dissipation effect, it is recommended to enlarge the copper foil area connected to the stem part on the back side of the product. The copper foil area of the printed circuit board significantly affects the heat dissipation effect. The inner frame stage on which the power transistor is mounted is connected to the VIN terminal (7, 8 pins). Therefore, the heat dissipation effect is increased by enlarging the copper foil area connected to the VIN terminal. As the junction temperature Tj (MAX) is a product-specific value, it must be observed strictly. For this purpose, heat sink design (thermal resistance of board) which is appropriate for Pd (MAX) and Ta MAX is required. This is graphically shown in the heat derating curve for easy understanding. The heat dissipation design is done in the following procedure. 1) The highest ambient temperature in the set Ta MAX is obtained. 2) The maximum loss PdMAX which varies the input/output conditions is obtained. Pd = (VIN - Vout) × Iout 3) The area of copper foil is determined from the graph of copper foil area (round shape to connect to 7, 8 pins) vs. permissible dissipation below shown. Copper foil area vs. Permissible dissipation Copper foil area (mm2) 10 SI-3010LLSL 6. Typical Characteristics - SI-3010LLSL *Set Vout = 1.5V 11 SI-3010LLSL SI-3010LLSL - *Set Vout = 1.5V 8) Thermal Shutdown Circuit 2.0 1.5 出力電圧 Vo 1.0 V 0.5 0 20 40 60 80 100 120 140 160 180 温度 Tj 12 SI-3010LLSL 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. 13