·       Low R_DS(ON) for Internal MOFETs: 17mΩ Top, 7.5mΩ Bottom

·       Wide Input Voltage Range: 5.5V ~ 24V

·       Adjustable Output Voltage: 1V ~ 12V

·       High Duty Cycle Capable using On-Time Stretch

·       11A Continuous Output Current Capability

·      100mA  LDO Current Capability

·       600kHz Pseudo-Constant Frequency

·       ±1% Internal Reference Voltage（V_REF）

·       Internal 0.8ms Soft-Start Limits the Inrush Current

·       Constant On-Time and Ripple-Based Control to Achieve Fast Transient Responses

·       Integrated 1.5Ω Bypass Switch

·       PFM/USM Selectable Light Load Operation Mode

·       Power Good Indicator

·       Output Auto-Discharge Function

·       Cycle-by-Cycle Valley and Peak Current Protection for buck

·       Latch-off Mode Output Under Voltage Protection for buck

·       Latch-off Mode Output Over Voltage Protection for buck

·       Latch-off Mode Over Temperature Protection for buck

·       Auto-recovery Mode Output Under Voltage Protection for LDO

·       Auto-recovery Mode Over Temperature Protection for LDO

·       Input Under Voltage Lockout(UVLO)

·       RoHS Compliant and Halogen Free

·       Compact Package: QFN3×4-13

The SY21249F is a high efficiency synchronous buck converter capable of delivering up to 11A current. It integrates low R_DS(ON) top and bottom MOSFETs to minimize the conduction loss. It operates at pseudo-constant frequency of 600kHz, to enable the use of small size inductor and capacitors. The SY21249F integrates a fixed 5V LDO with 100mA current capability, which can be used to power the external peripheries, such as the keyboard controller in the notebook. The 5V LDO can switch to bypass input to reduce power loss.

Silergy’s constant on-time and ripple-based control strategy supports high input/output voltage ratios (low duty cycles), and fast transient response while maintaining a near constant operating frequency over line, load and output voltage ranges. This control method provides stable operation without complex compensation, including when using low ESR output ceramic capacitors.

The SY21249F provides cycle-by-cycle current limit, input under voltage lockout, internal soft-start, output under voltage protection, over voltage protection and over temperature protection to guarantee safe operarion in all operating conditions.