1-1-3 DC/DC Converter ICs SI-8000Q Series Surface Mount, Current Mode Cntrol Step-down Switching Mode ■Features ■Absolute Maximum Ratings • Compact surface-mount package (HSOP8) Symbol Ratings Unit • Introduction of current mode control method Input Voltage VIN 30 V • Output current: 3.5 A Power Dissipation*1 PD 1.35 W Junction Temperature*2 Tj –30 to +150 °C Storage Temperature Tstg –40 to +150 °C Thermal Resistance(junction to case) θ j-c 40 °C/W Thermal Resistance(junction to ambient air) θ j-a 74 °C/W • High efficiency: 90% (Vo = 5 V) • Built-in reference oscillator (500 kHz) • A ceramic capacitor can be used for output • Built-in drooping-type overcurrent and thermal protection circuits Parameter Conditions When mounted on glass-epoxy board, 30×30 mm (copper laminate area: 25×25 mm) When mounted on glass-epoxy board, 30×30 mm (copper laminate area: 25×25 mm) *1: Limited by thermal protection circuit *2: Note that the detection temperature for thermal protection is about 140°C. • Built-in soft start circuit • Built-in on/off function (Active Hi) • Low current consumption during off ■Applications • DVD recorder, FPD-TV • Onboard local power supplies • OA equipment ■Recommended Operating Conditions Ratings Parameter Symbol Unit SI-8005Q Vo+3*1 DC Input Voltage Range VIN Output Voltage Range VO 0.5 to 24 to 28 Output Current Range IO 0 to 3.5 A Operating Junction Temperature Range Tjop –30 to +125 °C Operating Temperature Range Top –30 to +85 °C Conditions V V *1: The minimum value of the input voltage range is 4.75 V or Vo +3 V, whichever is higher. ■Electrical Characteristics (R1=4.2kΩ, R2=0.8kΩ when Ta = 25°C and Vo=5V) Rating Parameter SI-8005Q Symbol min. Reference Voltage Temperature Coefficient of Reference Voltage VADJ 0.485 Conditions Oscillation Frequency Line Regulation Load Regulation Overcurrent Protection Starting Current ∆VADJ/∆T 0.500 0.515 0.05 Conditions VIN=12V, Io=1A, Ta=–40 to +85°C Conditions VIN=12V, Io=1A 450 Conditions 550 30 Conditions 60 VIN=8 to 28V, Io=1A 30 ∆VOLOAD Conditions 60 VIN=12V, Io=0.1 to 3.5A 3.6 Conditions 6.0 VIN=12V Iq 18 Conditions Outflow Current at Low Voltage High Level Voltage EN Pin Low Level Voltage Inflow Current at Low Low Voltage 20 Conditions VIN=12V, Io=0A, VEN=0V Conditions VIN=16V, VSSL=0V ISSL 5 Vc/EN 2.2 VIN=12V Conditions VEN=0V IC/EH mV A µA V VIN=12V Vc/EL Conditions mV µA 2.8 Conditions kHz mA VIN=12V, Io=0A, VEN=open Iq(OFF) SS Pin % VIN=16V, Io=1A ∆VOLINE IS 500 V mV/ °C 90 fo Quiescent Circuit Current max. VIN=12V, Io=1A η Efficiency Unit typ. 5 V µA Error Amplifier Voltage Gain AEA 1000 V/V Error Amplifier Transformer Conductance GEA 800 µA/V Current Sense Amplifier Impedance 1/GCS 0.35 V/A Maximum ON Duty DMAX 92 % Minimum ON Time DMIN 100 nsec. *: Pin 8 is the SS pin. Soft start at power on can be performed with a capacitor connected to this pin. The SS pin is pulled up to the power supply in the IC, so applying the external voltage is prohibited. SI-8008Q 8 SS C8 30 ICs Soft start SI-8000Q Series ■External Dimensions (HSOP8) Pin Assignment 1BS 2IN 3SW 4GND 5FB 6COMP 7EN 0.08±0.08 6.20 4.40 Pin 1 Mark 0.05±0.05 (Unit : mm) Enlarged View of A 1.50 0.695 TYP 5.20 0.15 A 8SS 0.4 1.27 0.40 Plastic Mold Package Type 2.70 Flammability: UL 94V-0 2.90 Product Mass: Approx. 0.1 g ■Block Diagram 2 IN Current Sense Amp OSC Boot REG OCP 5v_ldo P.REG 1 BS VREF 0.5V PWM LOGIC ON OFF 7 EN OVP TSD Drive 3 SW 5v_ldo 6 COMP 5 FB Amp UVLO 0.5V 4 GND 8 SS ■Typical Connection Diagram VIN 7 2 IN 1 BS EN C4 R1 SI-8000Q 8 C1 SS GND COMP 6 C5 C6 OPEN C3 R3 VO L1 SW 3 FB 5 D1 GND 4 VFB C2 R2 IADJ GND C1:10µF/50V (Murata:GRM55DB31H106KA87) C2:22µF/16V (Murata:GRM32ER71A226KE20) C3:560pF*1 (Murata:GRM18 Type) C4:10nF (murata: GRM18 Type) C5:10nF (murata: GRM18 Type) L1:10µH D1: SPB-G56S (Sanken) SJPB-L4 (Sanken) R1:46kΩ (Vo=5V) R2:5.1kΩ R3:24kΩ *1 *1: When Vo=5V ICs 31