Torex Integrates Two Synchronous Step-Down DC/DCs In One Package

The IC operates from a supply voltage within a range of 2.7V to 6.0V and switching frequency can be selected from 1.2MHz or 3.0MHz to suit the application. As for operation mode, the XCM517 xA and xB models are available with PWM control and the XCM517 xC and xD models are user-selectable as either PWM or PWM/PFM automatic switching control via the CE/Mode pin. With the PWM/PFM automatic switching control mode, where ripple voltage control is normally difficult, the XCM517 achieves a low ripple operation of less than 10mV across the full load range and 92% efficiency (typ).

The XCM517 Series delivers a high efficiency and reliable power supply with up to 600mA output current per channel. The MCMs feature a built-in 0.42Ω P-channel MOSFET and 0.52Ω N-channel MOSFET; all that is required is a small 1.5μH (3MHz version) coil and ceramic capacitors connected externally. By using a separated EN (enable) input, ON/OFF control for each output of the circuit is available. Output voltage rise times as fast as 0.25ms (typ) can be achieved – 3MHz version with VOUT between 0.8V and 1.8V – with the help of a built-in high speed soft start function. Output voltage can also return to GND quickly with the help of a built-in CL discharge function.

When the XCM517 devices are in standby mode, the output becomes high impedance and the IC shuts down, reducing current consumption to a maximum of 1.0μA. The built-in UVLO (under voltage lock out) function, turns off the internal P-channel MOSFET when the input voltage drops to 1.4V or below.