XC9268 Series 36 V Operation 600mA Synchronous Step-Down DC/DC Converters ETR05071-001 ■GENERAL DESCRIPTION The XC9268 series are 36V operation synchronous step-down DC/DC converter ICs with a built-in P-channel MOS driver transistor and N-channel MOS switching transistor. The XC9268 series has operating voltage range of 3.0V~36.0V and high-efficiency power supply up to an output current of 600mA. Low ESR capacitors such as ceramic capacitors can be used for the load capacitor (CL). A 0.75V reference voltage source is incorporated in the IC, and the output voltage can be set to a value from 1.0V to 25.0V using external resistors (RFB1, RFB2). 1.2MHz or 2.2MHz can be selected for the switching frequency. In automatic PWM/PFM control, the IC operates by PFM control when the load is light to achieve high efficiency over the full load range from light to heavy. The soft-start time is internally set to 2.0ms (TYP.), but can be adjusted to set a longer time using an external resistor and capacitor. With the built-in UVLO function, the driver transistor is forced OFF when input voltage becomes 2.7V or lower. The output state can be monitored using the power good function. Internal protection circuits include over current protection and thermal shutdown circuits to enable safe use. ■APPLICATIONS ■FEATURES Input Voltage Range : 3.0 ~ 36V (Absolute Max 40V ● Electric Meter Output Voltage Range : 1.0 ~ 25V ● Gas Detector FB Voltage : 0.75V ± 1.5% ● Various Sensor Oscillation Frequency : 1.2MHz, 2.2MHz ● Industrial Equipment Output Current : 600mA ● Home appliance Quiescent Current : 12.5μA (1.2MHz) : 13.5μA (2.2MHz) Control Methods : PWM/PFM Auto : Efficiency 83%@12V→5V、1mA Soft-start Time : Adjustable by RC Protection Circuits : Over Current Protection : Thermal Shutdown Output Capacitor : Ceramic Capacitor Operating Ambient Temperature : - 40℃ ~ + 105℃ Packages : SOT-89-5 (Without Power Good) : USP-6C (With Power Good) Environmentally Friendly : EU RoHS Compliant, Pb Free ■TYPICAL APPLICATION CIRCUIT ■TYPICAL PERFORMANCE CHARACTERISTICS XC9268B75Cxx (V =12V, V =5V, f =1.2MHz) IN OUT OSC L=6.8μH(CLF5030NIT-6R8), CIN=4.7μF×2(C2012X6S1H475K) C L L=10μF×2 (C3216X7R1E106K) V 100 IN Lx 90 CIN R 2.2 FB1 μ F ] C 80 FB %[ EN/SS FB 70 C FFI 60 L R E FB2 10μ F×2 : 50 RPG y c 40 GN D PG ien 30 icff 20 E 10 0 0.1 1 10 100 1000 Output Current :I [mA] OUT 1/29
