SI-8010GL

1-1-3 DC/DC Converter ICs SI-8000GL Series Compact, Separate Excitation Step-down Switching Mode ■Features ■Absolute Maximum Ratings • DIP 8 pin package • Output current: 1.5A • High efficiency: 86% (at VIN = 20V, lO = 1A, VO = 5V) • Capable of downsize a choke-coil due to IC's high switching frequency (250kHz). (Compared with conventional Sanken devices) • The output-voltage-variable type can vary its output voltage from 1V to 14V because of its low reference voltage (Vref) of 1V. • Wide Input Voltage Range (8 to 50V) • Output ON/OFF available • Built-in overcurrent protection and thermal protection circuits Symbol Ratings DC Input Voltage Parameter VIN 53 Unit V Power Dissipation PD*1 1 W °C Junction Temperature Tj +125 Storage Temperature Tstg –40 to +125 °C Thermal Resistance (junction to case) θ j-c 28 °C/W Thermal Resistance (junction to ambient air) θ j-a 100 °C/W *1: Limited by thermal protection. ■Applications • Onboard local power supplies • OA equipment • For stabilization of the secondary-side output voltage of switching power supplies ■Recommended Operating Conditions Ratings Symbol Parameter Unit SI-8010GL DC Input Voltage Range VIN (8 or VO+3)*1 to 50 V Output Voltage Range VO 1 to 14 V Output Current Range*2 IO 0.02 to 1.5*2 A Operating Junction Temperature Range Tjop –30 to +125 °C Operating Temperature Range Top –30 to +125 °C *1: The minimum value of an input voltage range is the higher of either 8V or VO+3V. *2: Please be sure to let the output current run more than 20 mA. When using by less than 20 mA, there is a possibility that the output voltage becomes unstable. ■Electrical Characteristics (Ta=25°C) Ratings Parameter Symbol SI-8010GL (Variable type) min. Reference Voltage 0.97 FOSC Conditions Temperature Coefficient of Reference Voltage Overcurrent Protection Starting Current Quiescent Circuit Current Circuit Current at Output OFF 40 VIN=10 to 30V, IO=1A 10 ∆VOLOAD Conditions 30 VIN=12V, IO=0.1 to 1.5A 1.6 Conditions Iq Conditions 7 400 VIN=12V, VON/OFF=0.3V VSSL 0.5 Terminal Outflow Current at Low Voltage ISSL 50 *: Pin 2 is the CE/SS pin. Soft start at power on can be performed with a capacitor connected to this pin.The output can also be turned ON/OFF with this pin. The output is stopped by setting the voltage of this pin to VSSL or lower. CE/SS-pin voltage can be changed with an open-collector drive circuit of a transistor. When using both the soft-start and ON/OFF functions together, the discharge current from C4 flows into the ON/OFF control transistor. Therefore, limit the current securely to protect the transistor if C3 capacitance is large. The CE/SS pin is pulled up to the power supply in the IC, so applying the external voltage is prohibited. VSSL=0V ICs µA V µA SI-8000GL SI-8000GL SI-8000GL 2 CE/SS 2 CE/SS 2 CE/SS C4 VO. ON/OFF 42 mA VIN=12V, IO=0A Low Level Voltage Conditions mV A VIN=12V Iq(OFF) Conditions mV mV/°C ±0.5 ∆VREF/∆Ta IS kHZ VIN=12V, IO=1A 20 V % 250 Conditions Load Regulation 1.03 VIN=20V, IO=1A, VO=5V ∆VOLINE Line Regulation 1.00 86 Conditions Oscillation Frequency max. VIN=12V, IO=1A Eff Efficiency CE/SS* Terminal VREF Conditions Unit typ. Soft start C4 Soft start +VO. ON/OFF SI-8000GL Series ■External Dimensions (DIP8) 7 6 5 1 2 3 4 6.5±0.2 8 (Unit: mm) Pin Assignment 1. GND 2. CE/SS 3. Reg 4. SWOUT 5. VIN 6. B.S 7. Comp 8. VREF 1.0+0.3 -0.05 1.5+0.3 -0.05 7.6 7.5±0.5 4.2±0.3 3.4±0.1 9.4±0.3 +0.1 0.25-0. 05 3.3±0.2 Plastic Mold Package Type Flammability: UL 94V-0 Product Mass: Approx. 0.49 g 0.5±0.1 0.25 M 2.54 0° to 15° 0.89 TYP ■Block Diagram ■Ta-PD Characteristics SI-8010GL 2 PD=VO • IO 1.8 UVLO CE/SS P.REG Power Dissipation PD (W) VIN OCP CE/SS BS Boot REG TSD DRIVE Reg OSC + PWM LOGIC - SWOUT 100 VO –1 –VF • IO 1– ηχ VIN 1.6 Note 1: The efficiency depends on the input voltage and the output current. Therefore, obtain the value from the efficiency graph and substitute the percentage in the formula above. Note 2: Thermal design for D1 must be considered separately. 1.4 1.2 θ j-a:100°C/W 1 0.8 0.6 0.4 0.2 0 –25 VREF Comp Amp + 0 25 50 75 100 125 Ambient Temperature Ta (°C) 1V GND VO : Output voltage VIN : Input voltage IO : Output current ηχ : Efficiency VF : Diode D1 forward voltage RK16···0.4V(IO=1A) ■Typical Connection Diagram SI-8010GL 6 B.S R1 L1 C3 5 VIN VIN SI-8010GL V0 SWOUT 4 2 C1 + D1 R2 CE/SS C7 Reg 3 C4 C5 Comp GND 7 1 VREF + C2 8 R3 C8 IREF C1: 220µF/63V C2: 470µF/25V C3: 0.1µF C4: 1000pF C5: 0.1µF C6: 0.047µF C7: 0.1µF C8: 0.1µF R1: 47Ω L1: 47µH D1: RK16 (Sanken) C6 VREF (VOUT–VREF) (VOUT–1) 1 . GND = = (Ω), R3 = R2= = . 500(Ω) 2×10–3 IREF 2×10–3 IREF Diode D1 • Be sure to use a Schottky-barrier diode as D1. If other diodes like fast recovery diodes are used, IC may be destroyed because of the reverse voltage generated by the recovery voltage or ON voltage. Choke coil L1 • If the winding resistance of the choke coil is too high, the efficiency may drop below the rated value. • As the overcurrent protection starting current is approx. 2.5 A, take care concerning heat radiation from the choke coil caused by magnetic saturation due to overload or short-circuited load. Capacitor C1, C2 • As large ripple currents flow through C1 and C2, use high-frequency and low-impedance capacitors aiming for switching-mode-power-supply use. Especially when the impedance of C2 is high, the switching waveform may become abnormal at low temperatures. For C2, do not use a capacitor with an extremely low equivalent series resistance (ESR) such as an OS capacitor or a tantalum capacitor, which may cause an abnormal oscillation. Resistors R2, R3 • R2 and R3 are the resistors to set the output voltage. Set their values so that IREF becomes approx. 2 mA. Obtain R2 and R3 values by the following formula above. GND * To create the optimum operating conditions, place the components as close as possible to each other. ICs 43