XC9273 Series ETR05055-003 HiSAT-COT Control, 3.0A Synchronous Step-Down DC/DC Converters Green Operation-compatible GENERAL DESCRIPTION The XC9273 series is a group of synchronous-rectification type DC/DC converters with a built-in 47m P-channel MOS driver transistor and 36m N-channel MOS switching transistor, designed to allow the use of ceramic capacitors. The small on-resistances of these two internal driver transistors enable a high efficiency, stable power supply with an output current up to 3.0A. A 0.6V reference voltage source is incorporated, and the output voltage can be set freely by external resistors. Oscillation frequency is set to 1.2MHz or 3.0MHz can be selected for suiting to your particular application. The operation mode is HISAT-COT (*) control, which has an excellent transient response. PWM control or PWM/PFM auto switching control can be selected at the MODE1 pin, and a high-speed response, low ripple, and high efficiency are achieved across the entire load range (from light loads to heavy loads). As for the soft-start function as fast as 0.25ms in typical for quick turn-on. The soft start time can be set as desired by adding an external capacitance to the SS pin. Internal protection circuits include over current protection, short-circuit protection, and thermal shutdown circuits to enable safe use. Short circuit protection or Hiccup mode can be selected at the MODE2 pin. Soft-off function and C High Speed discharge function discharge the electric charge at the output capacitor C when putting the IC L L in a stand-by mode. Soft-off function can be selected at the MODE3 pin. (*) HiSAT-COT is a proprietary high-speed transient response technology for DC/DC converter which was developed by Torex. It is Ideal for the LSI s that require high precision and high stability power supply voltage FEATURES APPLICATIONS Input Voltage Range : 2.7V ~ 5.5V PC PFM control 0.6V ~ 3.6V Graphic board Output Voltage Range : PWM/PFM automatic switching control 0.8V ~ 3.6V Storage FB Voltage : 0.6V 1.0% Industrial application Output Current : 3.0A FPGA Oscillation Frequency : 1.2MHz, 3.0MHz SSD Efficiency : 95% (V =5.0V, V =3.3V, I =1.0A) IN OUT OUT ASIC Control Methods : HiSAT-COT Control DSP 100% Duty Cycle Mode select between Fixed PWM and PWM/PFM Auto Protection Functions : Thermal Shutdown Current Limit (Pendent character) HICCUP or Short Circuit Protection Functions : UVLO, Soft-Start, Soft-off C High Speed Discharge, Power good L Output Capacitor : Ceramic Capacitor Operating Ambient Temperature : -40 ~ 105 Package : QFN0404-24C Environmentally Friendly : EU RoHS Compliant, Pb Free TYPICAL APPLICATION CIRCUIT TYPICAL PERFORMANCE CHARACTERISTICS XC9273B06C, V =1.8V, fosc=1.2MHz L=0.56H(MWSA0603), OUT V IN PV IN R C =47F(GRM31CR61A476ME15L),C =47F(GRM31CR60J476ME19L),R =36k,R =18k,C =1500pF PG IN L FB1 FB2 FB R DD PG C IN AV 100 IN V OUT CE V OUT 80 L x MODE1 L V =5.0V IN PWM/PFM 60 MODE2 C C FB L R FB1 MODE3 40 FB PWM C C DD SS SS 20 R FB2 AGND PGND 0 1 10 100 1000 10000 Output Current : I (mA) OUT 1/30 Efficiency : EFFI (%) XC9273 Series BLOCK DIAGRAM XC9273 Short Current Limit Phase Protection HICCUP V OUT PV Compensation IN Error Amp. Comparator + Synch. - FB - Logic Buffer Lx S Q + Driver R Vref with Soft Start SS PGND Minimum On Time PV IN Generator V OUT CE Logic, PWM/PFM CE Control Selector UVLO, AV IN Thermal Shutdown MODE1 CL Auto-Discharge AGND MODE2 Power Good Comparator PG - MODE3 FB + * Diodes inside the circuit are an ESD protection diode and a parasitic diode. 2/30