1-1-3 DC/DC Converter ICs SPI-8000A Series Surface Mount, Separate Excitation Step-down Switching Mode ■Features ■Absolute Maximum Ratings • Surface-mount 16 pin package Parameter (Ta=25°C) Symbol Ratings Unit • Output current: 3.0A DC Input Voltage VIN 53 V • High efficiency: 91% (at VIN = 10V, lO = 1A, VO = 5V) Power Dissipation PD*1, *2 2.4 W Junction Temperature Tj +125 °C • Capable of downsizing a choke-coil due to IC's high switching frequency (125kHz). (Compared with conventional Sanken devices) Storage Temperature Tstg –40 to +125 °C Thermal Resistance (junction to case) θ j-c*2 18 °C/W Thermal Resistance (junction to ambient air) θ j-a*2 50 °C/W • The output-voltage-variable type can vary its output voltage from 1V to 14V because of its low reference voltage (Vref) of 1V. *1: Limited due to thermal protection. *2: When mounted on glass-epoxy board 700cm2 (copper laminate area 30.8cm2). • Wide Input Voltage Range (8 to 50V) • Output ON/OFF available • Built-in overcurrent and thermal protection circuits ■Applications • Onboard local power supplies • OA equipment • For stabilization of the secondary-side output voltage of switching power supplies ■Recommended Operating Conditions Ratings Parameter Symbol Unit SPI-8010A 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 3.0*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) Rating Parameter Symbol SPI-8010A (Variable type) min. Reference Voltage Line Regulation Load Regulation Temperature Coefficient of Reference Voltage Overcurrent Protection Starting Current Quiescent Circuit Current Circuit Current at Output OFF 1.00 1.03 % VIN=20V, IO=1A, VO=5V 250 Conditions kHZ VIN=12V, IO=1A 20 ∆VOLINE Conditions 40 mV VIN=10 to 30V, IO=1A 10 ∆VOLOAD Conditions 30 mV VIN=12V, IO=0.1 to 1.5A ∆VREF/∆Ta mV/°C ±0.5 3.1 Conditions Iq Conditions A VIN=12V 7 mA VIN=12V, IO=0A Iq(off) Conditions 400 µA VIN=12V, VON/OFF=0.3V Low Level Voltage VSSL 0.5 Outflow Current at Low Voltage ISSL 50 Conditions * Pin 4 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 opencollector 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 V µA SPI-8000A SPI-8000A SPI-8000A 4 CE/SS 4 CE/SS 4 CE/SS C4 VO. ON/OFF 22 V 86 FOSC IS max. VIN=12V, IO=1A Conditions Oscillation Frequency Terminal 0.97 Eff Efficiency CE/SS VREF Conditions Unit typ. Soft start C4 Soft start +VO. ON/OFF SPI-8000A Series ■External Dimensions (HSOP16) (Unit : mm) 1+0.1/-0.05 (Heatsink thickness) 10.5±0.2 9 1 8 10.5±0.3 2.5±0.2 2.75MAX 2.0+0.2/-0.08 16 0.25+0.15/-0.05 S 0.10 Pin Assignment 1.AGND 2.N.C 3.DGND 4.CE/SS 5.Reg 6.N.C 7.SWOUT 8.N.C 9.N.C 10.N.C 11.VIN 12.B.S 13.N.C 14.Comp 15.VREF 16.N.C S 12.2±0.2 (Gate remains: Not included in dimensions) (11) 8 (4.5) 7.5±0.2 (2) 1 16 9 1.27±0.25 Product Mass : Approx 0.86g 0.4+0.15/-0.05 ■Block Diagram SPI-8010A VIN UVLO CE/SS P.REG OCP CE/SS BS Boot REG TSD DRIVE Reg OSC + - PWM LOGIC SWOUT VREF Comp Amp + 1V GND ICs 23 1-1-3 DC/DC Converter ICs ■Typical Connection Diagram SPI-8010A 12 B.S R1 L1 C3 11 VIN VIN SPI-8010A SWOUT V0 7 4 C1 D1 R2 CE/SS + C7 Reg Comp AGND 5 C4 14 C5 1 DGND VREF + C2 15 R3 3 C8 IREF C6 GND GND 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: SPB-G56S (Sanken) Diode D1 • Be sure to use a Schottky-barrier diode for D1. If other diodes like fast recovery diodes are used, ICs 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 about 4.5A, take care concerning heat radiation from the choke coil caused by magnetic saturation due to overload or short-circuited load. Capacitors 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. 2mA. Obtain R2 and R3 values by the following formula: R2= VREF (VOUT–VREF) (VOUT–1) 1 .=500(Ω) = (Ω), R3 = = . IREF 2×10–3 IREF 2×10–3 To create the optimum operating conditions, place the components as close as possible to each other. ■Ta-PD Characteristics 3.00 Power Dissipation PD (W) PD=VO • IO 2.50 θ j-a:41.7°C/W(30.8cm2) θ j-a:47.6°C/W(8.64cm2) 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. 2.00 θ j-a:62.5°C/W(0.84cm2) 1.50 1.00 0.50 0 –30 0 25 50 75 100 Ambient Temperature Ta (°C) 24 ICs 100 VO –1 –VF • IO 1– ηχ VIN 125 VO : Output voltage VIN : Input voltage IO : Output current ηχ : Efficiency (%) VF : Diode D1 forward voltage SPB-G56S···0.4V(IO=2A)