600mA Synchronous Step-Down DC/DC Converters
The XC9235 series is a group of synchronous-rectification type DC/DC converters with a built-in 0.42ΩP-ch MOS driver transistor and 0.52ΩN-ch MOS switching transistor, designed to allow the use of ceramic capacitors. Operating voltage range is from 2.0V to 6.0V (types A～C), 1.8V to 6.0V (types D～G). For the D/F types which have a reference voltage of 0.8V (±2.0%), the output voltage can be set from 0.9V by using two external resistors. The types A/B/C/E/G have a fixed output voltage from 0.8V to 4.0V in increments of 0.05V (±2.0%). The device provides a high efficiency, stable power supply with an output current of 600mA to be configured using only a coil and two capacitors connected externally. With the built-in oscillator, either 1.2MHz or 3MHz can be selected for suiting to your particular application.
The soft start and current control functions are internally optimized. During stand-by, all circuits are shutdown to reduce current consumption to as low as 1.0μA or less. The types B/F/G have a high speed soft-start as fast as 0.25ms in typical for quick turn-on. With the built-in UVLO (Under Voltage Lock Out) function, the internal P-channel MOS driver transistor is forced OFF when input voltage becomes 1.4V or lower.
The types B to G integrate 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 VSS pins. When the devices enter stand-by mode, output voltage quickly returns to the VSS level as a result of this function.
Three types of package SOT-25, USP-6C, and USP-6EL and WLP-5-03 are available.
Typical Application Circuit
|P-ch Driver Transistor||0.42Ω|
|N-ch Switch Transistor||0.52Ω|
|Input Voltage Range||2.0～6.0V(Types A/B/C),1.8V～6.0V(Types D/E/F/G)|
|Output Voltage Range||0.8～4.0V|
|Capacitor||Low ESR Ceramic|
|Functions||CL High Speed Auto Discharge(B/C/D/E/F/G),High Speed Soft Start(B/F/G)|