The XC9131 and XC9135/36 synchronous step-up DC/DC converters from Torex can be used with ceramic capacitors and integrate one P-channel and one N-channel MOS power transistors. The converters can start operation from VIN between 0.9 and 5.5V, making them suitable for mobile equipment using a single alkaline or nickel metal hydride battery. Once the start-up procedure is over, the converters will carry on operating for input voltages down to 0.65V.
The output voltage is selectable between 1.8 and 5.0V. In the case of the XC9135/36, this output voltage is set internally and is available in 0.1V increments, whereas in the XC9131 the output voltage can be adjusted externally with two resistors. The output current that the converters can supply will depend on the VIN, VOUT conditions, with up to 500mA of output current supplied at VIN=1.8V and VOUT=3.3V.
The converters feature a soft-start circuit, an enable pin to turn the IC on and off, and a load disconnect function that prevents the battery charge from leaking to the output while the IC is not operating. They are available with a CL discharge function that discharges the output capacitor when the IC is turned off. The protection circuits of the converters comprise a thermal shutdown circuit and a current limiting circuit. The XC9135 also available with an output voltage drop protection function, includes a UVLO function that reduces the leaking of potassium hydroxide by stopping IC operation when the battery voltage drops below a selectable threshold. The converters are available in a small 2.9 x 2.6mm USP-10B package.
