This demonstration board is based on the ST1S12 family of synchronous step-down DC-DC converters optimized for powering low-voltage digital cores in HDD (hard disk drive) applications, and is generally used to replace high-current linear solutions when power dissipation may cause high heating of the application environment. It provides up to 0.7 A over an input voltage range of 2.5 V to 5.5 V. A high switching frequency of 1.7 MHz allows the use of tiny surface-mount components. A resistor divider to set the output voltage value, an inductor, and two capacitors are required for the adjustable version, while only an inductor and 2 capacitors are needed for the 1.2 V and 1.8 V fixed version.
A low output ripple is guaranteed by the current mode PWM topology and by the use of low ESR surface-mount ceramic capacitors.
The ST1S12 device is thermal protected and current limited to prevent damage due to accidental short-circuit. This family of products is available in the TSOT23-5L package.