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. For the adjustable version, a resistor divider to set the output voltage value, an inductor, and two capacitors are required. 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.
- RDS(on) typ. 250 m and 400 m
- Not switching quiescent current: max 600 μA over temperature range
- Uses tiny capacitors and inductors
- Internal soft-start
- Enable function
- Step-down current mode PWM (1.7 MHz) DCDC converter
- 0.7 A output current capability
- Fixed output voltage of 1.2 V
- Synchronous rectification
- Typical efficiency: > 90%
- 3% DC output voltage tolerance