The XC9106 / 07 series are step-up DC/DC controller ICs with an externally applied reference voltage (Vref). Output voltage will be set with external resistors (RFB1 and 2) and Vref value. The series make it easy to control output voltage externally and are suited to software applications that need to vary voltage, such as LCD power supply for PDA. Output will be stable no matter which load capacitors are used but if a low ESR capacitor is used, RSENSE of about 0.1 will be required and phase compensation will be achieved. This makes the use of ceramic capacitors much easier, and allows for lower output ripple and reduced PCB area requirements. Tantalum and electrolytic capacitors can also be used, in which case, RSENSE becomes unnecessary. Oscillation frequencies of high clock, low ripple 300kHz and low supply current 100kHz are available. The XC9107 series are PWM/PFM automatic switching controlled. Control switches from PWM to PFM during light loads with the XC9107 and the series is highly efficient from light loads to large output currents. By bringing the whole circuit down while the series is in the stand-by mode (CE/PWM pin: low), supply current can be reduced to less than 1.0A.