DC/DC转换器和控制器 XC9244~XC9245

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概要

The XC9244/XC9245 series is a group of synchronous-rectification type step-down DC/DC converters with a built-in 0.65Ω P-channel MOS driver transistor and 0.45Ω N-channel MOS switching transistor, designed to allow the use of ceramic capacitors. Output current of 400mA (MAX.) to be configured using only a coil and capacitor connected externally.
The output voltage can be set from 0.8V to 4.0V in increments of 0.05V (accuracy: ±2.0%). With an internal switching frequency of 1.2MHz, small external components can be used. USPN-6 package is suitable for the application which requires low profile and small-footprint.
The XC9244 series is PWM fixed frequency control, and the XC9245 series is PWM/PFM, which automatically switches from PWM to PFM during light loads, high efficiency can be achieved over a wide range of load conditions. When stand-by mode, due to stop all operation, supply current is reduced to 1μA or less. The integrated CL discharge function which enables the electric charge at the output capacitor CL to be discharged via the internal discharge switch located between the VOUT and VSS pins. The CL discharge function prevents malfunction on VOUT connecting application during stand-by mode.
The XC9244/XC9245 series has a high speed soft-start as fast as 0.25ms in typical for quick turn-on. Current limiter circuit (Constant Current & Latching) is built-in for preventing from thermal destruction. With UVLO (Under Voltage Lock Out) function, the internal P channel driver transistor is forced OFF when input voltage becomes 2.25V or lower.

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