XC9274/XC9275 Series ETR05056-004 HiSAT-COT Control 3.0A Synchronous Step-Down DC/DC Converters Green Operation-compatible GENERAL DESCRIPTION The XC9274/XC9275 series is a group of synchronous-rectification type DC/DC converters with a built-in 51m P-channel MOS driver transistor and 49m 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, the XC9274 series is PWM control, the XC9275 series is PWM/PFM auto switching control, allowing fast response, low ripple, and high efficiency over the full range of loads (from light loads to heavy loads). During stand-by, all circuits are shutdown to reduce current consumption to as low as 1.0A or less. As for the soft-start function as fast as 0.25ms in typical for quick turn-on. Internal protection circuits include over current protection, short-circuit protection, and thermal shutdown circuits to enable safe use. Short-circuit protection is available only for B,C type. Hiccup mode is available only for D,E type. Soft-off function is available only for B, D type. The package is the SOP-8FD. (*) 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 APPLICATIONS FEATURES PC Input Voltage Range : 2.7V ~ 5.5V Graphic board XC9274 : 0.6V ~ 3.6V Output Voltage Range : Storage XC9275 : 0.8V ~ 3.6V Industrial application FB Voltage : 0.6V 1.0% FPGA Output Current : 3.0A SSD Oscillation Frequency : 1.2MHz, 3.0MHz ASIC Efficiency : 95% (V =5.0V, V =3.3V, I =1.0A) IN OUT OUT DSP Control Methods : HiSAT-COT Control : 100% Duty Cycle : PWM Control (XC9274) : PWM/PFM auto switching Control (XC9275) Protection Functions : Thermal Shutdown : Current Limit (Pendent character) : HICCUP (D,E Type) Short Circuit Protection (B,C Type) Functions : UVLO, Soft-Start : Soft-off (B,D Type) : C High Speed Discharge, Power good L Output Capacitor : Ceramic Capacitor Operating Ambient Temperature : -40 ~ 105 Package : SOP-8FD TYPICAL PERFORMANCE TYPICAL APPLICATION CIRCUIT CHARACTERISTICS V =3.3V, fosc=1.2MHz L=0.82H(MWSA6030),C =47F(GRM31CR61A476ME15L) OUT IN C =47F(GRM31CR60J476ME19L),R =68k,R =15k,C =820pF L FB1 FB2 FB V IN PV IN R PG 100 PG 90 80 V OUT CE 70 VIN = 5.0V V OUT XC9275 L x 60 L 50 40 C C C IN FB L RFB1 30 XC9274 FB 20 10 R FB2 0 AGND PGND 1 10 100 1000 10000 Output Current : IOUT (mA) 1/28 Efficiency : EFFI (%) XC9274/XC9275 Series BLOCK DIAGRAM 1) XC9274/XC9275 Short Current Limit Phase Protection V Hiccup OUT V Compensation IN Error Amp. Comparator + Synch. - FB - Buffer Lx S Q Logic + Driver R Vref with Soft Start PGND Minimum V On Time IN Generator V OUT FUNCION selector CE PWM/PFM CE Control Selector UVLO, Thermal Shutdown CL Auto-Discharge AGND SOFT - OFF Power Good Comparator PG - FB + * In the XC9274 seriesPWM / PFM Selecto is fixed to PWM control. In the XC9275 seriesPWM / PFM Selecto is fixed to PWM / PFM automatic switching control. For Hiccup, Short Protection, Soft-off, the available functions are different for each product type. Please refer to Selection Guide for functions available for each product type. Diodes inside the circuit are an ESD protection diode and a parasitic diode. 2/28