Torex Announces Small 400mA Synchronous Step-Down DC-DC Converters

Torex Semiconductor Ltd. has developed a new 400mA synchronous step-down dc-dc converter. The XC9244/XC9245 series is a synchronous step-down dc-dc converter with an output current of 400mA. Using the ultra-small USPN-6 package and only a coil and two capacitors as external components, these converters contribute to a reduction of mounting area and space saving.

The operating voltage range is 2.3 to 6.0V. The output voltage range is 0.8 to 4.0V (accuracy ±2.0%) and can be selected in steps of 0.05V. The XC9244 series is PWM control providing a stable switching frequency that minimizes output ripple. The XC9245 series is PWM/PFM auto switching control providing high efficiency and low output ripple over the full load range.

Both series incorporate a 0.25ms（TYP.）high-speed soft-start function. The CL high-speed discharge function turns on the internal switch between VOUT and VSS during standby to quickly discharge the CL load capacitor charge. The stand-by current is 1.0µA or less. Current limiting (700mA MIN.) and a UVLO function, that forces the internal driver transistor off at an input voltage of 2.25V (MAX.) or less, are incorporated as protection functions.

The XC9244/XC9245 series features include: ultra-small USPN-6 package size (1.3 x 1.3 x h 0.4 mm); stable supply with high efficiency (90% TYP.) is possible; with a switching frequency of 1.2MHz, 3.2 x 3.0 x h1.2mm size external coil and a 1608 size external capacitor can be selected; and includes a high-speed soft-start function, CL high-speed discharge function, current limiting, and a UVLO function.