XC9105 Series

Ceramic Cap. Compatible Step-up DC/DC Controllers

The XC9105 series are PWM, PWM/PFM auto switching /manual switching controlled multi-functional step-up DC/DC controllers.

Output will be stable no matter which load capacitors are used but should a low ESR capacitor be used, RSENSE of about 0.1Ω 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.

With 0.9V of standard voltage supply internal, and using externally connected components, output voltage can be set up freely within a range of 1.5V to 30V. With 300kHz or 180kHz frequencies, the size of the external components can be reduced. Oscillation frequencies of 100kHz and 500kHz are also available as custom-designed products.

The XC9105 offers both PWM and PWM/PFM auto switching operations and it can be selected by external signal.

Typical Application Circuit


Input Voltage Range 0.9V~10V
Power Supply Voltage Range 1.8V~10V
Output Voltage Range 1.5V~30V,Can be set freely with 0.9V(±2.0V) of reference voltage supply and external registors.
Oscillation Frequency 100,180,300,500kHz(±15%)
Output Current More than 400mA (VIN=1.8V,VOUT=3.3V)
Control PWM
High Efficiency 85%(TYP.)
Stand-by Current ISTB=1.0μA(MAX.)
Load Capacitors Low ESR capacitors compatible



Technical Document

Quality Reports


QuestionWhat is the soft-start function?

The function to soften the rise to prevent the inrush current.

QuestionWhat is the standby current?

The current that flows through the IC in the standby mode. The standby mode means the state where the IC has been turned off by the CE function.

QuestionHow does the GO function of DC/DC converters work? Does it work just like a regulator?

Torex regard the PWM/PFM automatic switch control function as Green Operation (GO) in the case of DC/DC. The GO function is defined as the switching operation between the PFM mode for a small output current and the PWM mode for a large output current. The PFM control method controls the output current by increasing and decreasing the fall time according to the output current while keeping a pulse width. The PWM control method controls the output current by adjusting the pulse width of the rise time, which keeps the rise/fall time interval constant and increases the efficiency at a heavy load. By switching between the PFM control for a small output current and the PWM control for a large output current, the quiescent current can be controlled for both of heavy and light loads.

QuestionWhat does the FB product mean?

An IC for which any output voltage can be set by the reference voltage of the FB pins and the external dividing resistor. The output voltage is determined by the RFB1 and RFB2 values, using the following formula: VOUT = Vref × (RFB1 + RFB2)/RFB2