XC9280 Series ETR05064-003 18V Operation 3.0A Synchronous Step-Down DC/DC Converters GENERAL DESCRIPTION The XC9280 series is 18V bootstrap synchronous step-down DC/DC converter with built-in Nch-Nch driver transistors, the operating voltage range is 4.5V~18.0V, designed to allow the use of ceramic capacitors. 0.75V reference voltage source is incorporated in the IC, and the output voltage can be set to a value from 1.8V to 7.0V using external resistors (RFB1, RFB2). Switching frequency is 1.2MHz. In PWM/PFM automatic switchover control, IC can change the control method between PWM and PFM based on the output current requirement and as a result IC can achieve high efficiency over the full load range. XC9280 has a fixed internal soft start time which is 0.95ms (TYP.), additionally the time can be extended by using an external resistor and capacitor. With the built-in UVLO function, the driver transistor is forced OFF when input voltage goes down to 3.33V (TYP.) or lower. Over current protection and thermal shutdown are embedded and they secure a safety operation. FEATURES APPLICATIONS Input Voltage Range : 4.5V ~ 18V (Absolute Max 20V) Digital TV Output Voltage Range : 1.8V ~ 7.0V or VIN x 0.7 Set Top Box FB Voltage : 0.75V1.5% Security camera Oscillation Frequency : 1.2MHz Smart meter Output Current : 3A peak Security system 2.0A DC (VIN=12V, VOUT=5V) Control Method : PWM/PFM Automatic Soft-start Time : 0.95ms Adjustable by RC Protection function : UVLO Over Current Protection (Automatic Recovery) Thermal Shutdown Output Capacitor : Ceramic Capacitor Package : TSOT-26 Environmentally Friendly : EU RoHS Compliant, Pb Free TYPICAL PERFORMANCE TYPICAL APPLICATION CIRCUIT CHARACTERISTICS V BST IN C IN (ceramic) CBST L EN/SS Lx R FB1 C FB GND FB C L (ceramic) R FB2 1/28 XC9280 Series BLOCK DIAGRAM VIN Local Reg EN EN/SS UVLO Control Logic Current BST Feedback Control Thermal BST Switch Shutdown Current Limit Nch Highside Current Limit PFM DRV Tr. Output Soft Buffer VREF + L X Start ERR AMP - PWM/PFM Nch Phase Compensation Control Logic Lowside PWM DRV Tr. Comparator Ramp Wave Generator, GND OSC FB * Diodes inside the circuit are an ESD protection diodes and a parasitic diodes. PRODUCT CLASSIFICATION 1) Ordering Information (*1) XC9280 - DESIGNATOR ITEM SYMBOL DESCRIPTION Type A Refer to Selection Guide FB Voltage 75 0.75V Oscillation C 1.2MHz Frequency Packages (*1) (*1) - YR-G TSOT-26 (3,000pcs/Reel) (Order Unit) (*1) The -G suffix denotes Halogen and Antimony free as well as being fully EU RoHS compliant. 2) Selection Guide Thermal TYPE Chip Enable UVLO Shutdown A Yes Yes Yes Current Automatic Recovery TYPE Soft Start Limiter (Current Limiter) A Yes Yes Yes 2/28