5.5V synchronous step‐down DC/DC converters deliver up to 3A

February 21, 2017 // By Julien Happich
The XC9273 from Torex Semiconductor is a Step‐Down DC/DC Converter that utilises Hi‐SAT COT, Torex’s own ‘Constant On‐Time’ architecture, to deliver extremely fast transient response performance and high efficiency.

With Hi‐SAT COT the XC9273 only needs one low cost 47μF ceramic capacitor at the output side, whilst competitors often need multiple capacitors to achieve similar levels of performance. Hi‐SAT COT also provides less fluctuation in oscillation frequency against load and input voltage when compared to traditional COT control architectures. Adding extra capacitance at the output will allow the user to reduce output ripple further if required. With a 0.6V ±1.0% reference voltage source the output voltage can be set freely from 0.8V using external resistors. Furthermore, it is possible to control the output voltage dynamically using an external digital‐to-analog converter (DAC). Users can choose either a 1.2MHz or 3.0MHz switching frequency and an output up to 3.0A from an input voltage range of 2.7V to 5.5V. The XC9273 also allows the engineer to select different features using the MODE pins. Using a High or Low signal the engineer can select PWM control or PWM/PFM auto switching control, Short Protection with latch or hiccup mode and optional CL discharge with soft OFF. The integral soft start time can be adjusted with an external capacitor (CSS) and a Power Good feature is also included to help with system power‐up sequencing. Samples are available now in a 4.0x4.0x0.75mm QFN0404‐24C package.

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