SY21228A -


·       Fast Transient Response

·       Wide Input Voltage Range: 4-28V

·       Internal 20mΩ Power Switch And 10mΩ Synchronous Rectifier

·       8A Continuous/16A Peak Output Current Capability

·       Accurate Feedback Reference Voltage: 0.6V ±1 %

·       Pseudo-Constant 800kHz Operating Frequency

·       Automatic High Efficiency Discontinuous Operating Mode at Light Loads

·       Internal 600µS Soft-Start Limits Inrush Current

·       Programmable Valley Current Limit

·       Power Good Indicator

·       Output Discharge Function

·       Cycle-By-Cycle Current Limit

·       Hiccup Mode Output Short Circuit And Over Voltage Protection

·       Over Temperature Protection

·       Compact Package: QFN3x3-12

Typical Application


The SY21228A is a high-efficiency synchronous step down DC/DC regulator featuring internal power and synchronous rectifier switches capable of delivering 8A of continuous output current and up to 16A peak output current over a wide input voltage range of 4V to 28V.


Silergy’s proprietary Instant-PWM™ fast-response, constant-on-time (COT) PWM control method 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 and even with low ESR ceramic capacitors.


Internal 20mΩ power and 10mΩ synchronous rectifier switches provide excellent efficiency over a range of applications, especially for low output voltages and low duty cycles. Cycle-by-cycle current limit, input under-voltage lock-out, internal soft-start, output under- and over-voltage protection, and thermal shutdown provide safe operation in all operating conditions.


The SY21228A is available in a compact QFN3X3-12 package.


·       LCD-TV/Net-TV/3DTV

·       Set Top Box

·       Notebook

·       High Power AP