XC9248 Series ETR05022-008 18V Driver Transistor Built-In Synchronous Step-Down DC/DC Converter GENERAL DESCRIPTION The XC9248 series is 18V bootstrap synchronous step-down DC/DC converter with built-in Nch-Nch driver transistors. With an input voltage range from 4.5V to 18V and a maximum output current of 2.2A, the series is suitable for digital home appliance power supplies and can be used with small ceramic capacitors. The series has a 0.8V reference voltage, and using externally connected resistors, the output voltage can be set freely from 1.0V to 12V. The control method is synchronous PWM (Source/ Sink). The soft start time is internally set to 2.8ms (TYP.), also can be adjusted using external capacitor. With UVLO (Under Voltage Lock Out) function, the internal driver transistors are forced OFF when input voltage falls down below 3.8V (TYP.). The series includes over current protection, VOUT short-circuit protection, Lx short-circuit protection, VOUT overvoltage protection and thermal shutdown. APPLICATIONS FEATURES Input Voltage 4.5V ~ 18V Digital home appliance (*1) Output Voltage 1.0V ~ 12V (V =0.8V1.5%) FB Office automation equipment Output Current 2.2A (*1) Note PCs / Tablet PCs Efficiency 93.8% V =12V,V =5V, I =700mA IN OUT OUT Oscillation Frequency 500kHz Car accessories power supplies Maximum Duty Cycle 79% Soft-Start Time Fixed 2.8ms, set by external capacitor Protection Circuit UVLO High side over current protection Low side over current protection V Short-circuit Protection OUT L Short-circuit Protection X V Over voltage protection OUT Thermal shutdown Package SOP-8FD Environmentally Friendly EU RoHS Compliant, Pb Free (*1) Performance depends on external components and wiring on the PCB. TYPICAL APPLICATION CIRCUIT TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs. Output Current L Ta=25C V V L V IN IN X OUT 100 90 EN EN GND C BST CFB RFB1 80 SS BST 70 V =12V , V =5V IN OUT 60 V FB L 50 V =12V , V =3.3V IN OUT 40 C C C C R IN SS VL L FB2 30 20 10 0 0 500 1000 1500 2000 Output Current : I mA OUT 1/21 Efficiency % XC9248 Series BLOCK DIAGRAM EN ENB EN V IN SHORT to internal ILIM circuits Latch Delay Control Block VIN UVLO V L VL VL UVLO LX SHORT SS Thermal Current Feedback Shutdown BST Current Limit ILIM Nch - DRV OVP + Soft Output VREF + L X Start Buffer ERR AMP Nch - DRV Phase Compensation PWM + Comparator ENB IREF SHORT SHORT Ramp Wave - Generator, GND OSC FB * Internal diodes include an ESD protection diode and a parasitic diode. PRODUCT CLASSIFICATION Ordering Information XC9248- DESIGNATOR ITEM SYMBOL DESCRIPTION A TYPE Refer to Selection Guide B FB Voltage 08 FB voltage is fixed in 0.8V Oscillation Frequency 5 500kHz (*1) - Package QR-G SOP-8FD (1,000pcs/Reel) (*1) The -G suffix denotes Halogen and Antimony free as well as being fully EU RoHS compliant. Selection Guide LATCH FOR LATCH FOR LATCH FOR TYPE CURRENT LIMITER (*2) CURRENT LIMITER VOUT-SHORT LX-SHORT (*1) A YES YES YES YES B YES NO NO YES CL THERMAL TYPE ENABLE UVLO AUTO-DISCHARGE SHUTDOWN A YES YES YES YES B YES YES YES YES (*1) The over-current protection latch is an integral latch type. (*2) To prevent an extremely large rush current from flowing in the event that Lx is short-circuited, both the A & B types have an Lx short protection latch function. 2/21