The XCL221/XCL222 series is a synchronous step-down micro DC/DC converter which integrates an inductor and a control IC in one tiny package (2.0mm×2.5mm, h=1.0mm). An internal coil simplifies the circuit and enables minimization of noise and other operational trouble due to the circuit wiring. A wide operating voltage range of 2.5V to 5.5V enables support for applications that require an internally fixed output voltage (0.8V to 3.6V). The XCL221/XCL222 series uses synchronous rectification at an operating frequency of 1.2MHz. The XCL221/XCL222 series uses HiSAT-COT (*) synchronous rectification. HiSAT-COT+PWM control (XCL221) or HiSAT-COT+automatic PWM/PFM switching control (XCL222) can be selected.

The series have a high speed soft-start as fast as 0.25ms (TYP.) in typical for quick turn-on. With the built-in UVLO (Under Voltage Lock Out) function, the internal P-channel driver transistor is forced OFF when input voltage becomes 2.0V or lower. When CE=Low, 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 LX and PGND pins. The power consumption will be less than 1.0μA. 

(*) HiSAT-COT is an original Torex term for High Speed Transient Response.