XC9111 Series

PFM Controlled Step-Up DC/DC Converter

The XC9111 series is a group of PFM controlled step-up DC/DC converter/controller ICs designed to generate low supply voltage by the combination of PFM control and CMOS structure. The series is ideal for applications where a longer battery life is needed such as in portable communication equipment. With a built-in 2.5ΩN-channel driver transistor, the XC9111C/E types provide a step-up operation by using only a coil, a capacitor, and a diode connected externally.

The XC9111B, D and F versions can be used with an external transistor for applications requiring larger currents.

Output voltage is internally programmable in a range from 1.5V to 7.0V in increments of 0.1V (±2.5%).

Maximum oscillation frequency is set to 100kHz for XC9111 series. (At light loads, it is set to 180kHz for the XC9111 series.) Options include products equipped with a CE pin (C and D versions) that allows the IC to be shut down thereby reducing quiescent current and with separated VDD/VOUT pins (E and F versions) to separate the power supply block and the output voltage detect block. The XC9111 series automatically switches duty ratio between 56% & 75% (VDD=3.3V) when it senses changes in load to drop output ripple voltage and can support both large and small currents. The external transistor types (B/D/F types) can be provided for applications, which require larger currents.

Typical Application Circuit


Operating (Input) Voltage Range 0.9V~10.0V
Output Voltage Range 1.5V~7.0V (0.1V increments)
Maximum Oscillation Frequency 100kHz,*180kHz (duty ratio:56% at light loads)
Built-in Switching N-ch Transistor Types A/C/E
On Resistance 2.5Ω(VDD=3.0V)
External Transistor Types Types B/D/F
Lx Limit Voltage Type E : More than VDD=2.0V, Types A/C : More than VOUT=2.0V



Technical Document

Quality Reports


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.

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