1- 1-3 DC/DC Converter ICs SI-8000Q Series Surface Mount, Current Mode Control Step-down Switching Mode ■ Features ■ Absolute Maximum Ratings • Compact surface-mount package (HSOP8) Parameter Input Voltage Symbol • Output current: 3.5A Power Dissipation*1 PD • High efficiency: 90% (Vo = 5 V) Junction Temperature*2 Tj –30 to +1 50 °C Tstg –40 to +1 50 °C • Introduction of current mode control method • Built-in reference oscillator (500 kHz) Storage Temperature Ratings 30 VIN Unit V 1.35 W • A ceramic capacitor can be used for output Thermal Resistance (junction to case) θj-c 40 °C/W • Built-in drooping-type over current and thermal protection circuits Thermal Resistance (junction to ambient air) θj-a 74 °C/W • Built-in soft start circuit • Built-in on/off function (Active Hi) Conditions When mounted on glass–epoxy board, 30×30 mm (copper laminate area : 25×25 mm) When mounted on glass epoxy board, 30×30mm (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. • Low current consumption during off ■ Applications • DVD recorder, FPD-TV • Onboard local power supplies • OA equipment ■ Recommended Operating Conditions Parameter Symbol Ratings SI-8005Q Unit DC Input Voltage Range VIN Vo+3*1 to 28 V Output Voltage Range VO 0.5 to 24 V Output Current Range IO 0to3.5 Conditions A Operating Junction Temperature Range Tjop –30 to +125 °C Operating Temperature Range Top –30 to +85 °C *1 : The minimum value of the input voltage range is 4.75 V or Vo +3 V, whichever is higher. ■ Electrical Characteristics Parameter (R1=46kΩ, R2=5.1kΩ when Ta = 25°C and Vo=5V) Rating SI-8005Q Symbol min. Reference Voltage Temperature Coefficient of Reference Voltage 0.485 VADJ Conditions Conditions 90 fo Over current Protection Starting Current 450 Conditions Conditions 500 550 60 VIN=8 to 28V, Io=1 A 30 ∆VOLAD Conditions 60 VIN=12V, Io=0.1 to 3.5A 3.6 6.0 Conditions VIN=12V Iq 18 Conditions Quiescent Circuit Current 5 Conditions Low Level Voltage Inflow Current at Low Low Voltage mV A V Conditions VIN=12V 2.2 Vc/L Conditions VIN=12V 5 IC/E H µA µA VIN=1 6V, VSSL=0V 2.8 Vc/N EN Pin VIN=12V, Io=0A, VEN=0V ISSL High Level Voltage mV mA 20 Conditions Outflow Current at Low Voltage kHz VIN=12V, Io=0A, VEN=open Iq(OFF) SS Pin % VIN=16V, Io=1A 30 IS V mV/°C VIN=12V, Io=1A ∆VOLNE Load Regulation 0.515 VIN=12V, Io=1 A, Ta=–40 to +85°C Conditions Line Regulation 0.500 0.05 η Oscillation Frequency max. VIN=12V, Io=1A ∆VADJ/∆T Efficiency Unit typ. Conditions VEN=0V V µA Error Amplifier Voltage Gain AEA 1000 Error Amplifier Transformer Conductance GEA 800 V/V 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:SJPW-T4 (Sanken) R1:46kΩ (Vo=5V) R2:5.1kΩ R3:24kΩ *1 *1: When Vo=5V ICs 33