New Industry Products

Silanna Semiconductor Launches a Line of Tiny Buck Regulators for USB Applications

November 18, 2020 by Gary Elinoff

The 65 watt DC/DC converters can switch at 2MHz, operate with a DC input ranging up to 24 volts, and are offered in 3mm X 3mm QFN packages

The SZPL3102A/3103A family of DC-DC converters (Buck Regulators) are point-of-load converters aimed at USB-PD applications. Their high efficiency and power density empowers designers to deliver solutions at lower cost and at greatly reduced physical size. 


The SZPL3102A/3103A family of Buck Regulators.
The SZPL3102A/3103A family of Buck Regulators. Image courtesy of Silanna Semiconductor


Tim Wilhelm, Director of Marketing, explained, “Higher switching frequency means a smaller, lower-cost output filter that has delighted the clients we have sampled.  The SZPL3102/3103 have ground-breaking efficiencies in the smallest size and weight designs. Our support tools give customers the flexibility and confidence to quickly increase the performance efficiency which ultimately increases the power density in their designs approaching 12% of the volume required by low-frequency competitive solutions.  The SZPL3102/3103 significantly reduce BOM cost, design cycles and time to market.”  


Main Characteristics of the SZPL3102 and the SZPL3103

The SZPL3102A and SZPL3103A feature exceptionally low operating power dissipation, leading to low no-load power, which is a necessary specification for regulatory certification for USB port power supply applications. 

  • Switching frequency is selectable over a range of 667 kHz to 2 MHz, making compact design possible.
  • These buck regulators accept inputs ranging from 8 to 27 VDC
  • Outputs from 3.3 to 21 VDC at 3.25 amps cover programmable power supply (PPS) and USB-PD 3.0 applications
  • Up to 65 watts of power
  • Over-current, over-voltage, and over-temperature protections
  • Programmable under-voltage lockout (UVLO)


The SZPL3102A contains a momentary internal feedback path allowing for a well-controlled start-up operation while the external USB-PD controller makes ready take over control of the output voltage. 


SZPL3102A applied to a USB-PD port application.
SZPL3102A applied to a USB-PD port application. Image courtesy of  SZPL3102A/3103A data sheet


The SZPL3103 works with an external feedback resistor divider for stand-alone operation or it can co-operate with other USB port controllers, themselves containing an external divider network. 


Reference Design 

The RD-05, a 65W Dual Type-C  (2C) Port Charger. This design employs Silanna’s SZPL3103 65-watt buck converter along with the company’s SZ1130 65 Watt active-clamp flyback (ACF) controller. When fully cased, this 65 watt all-silicon solution measures a scant 61 x 47 x 32 mm, which translates to a power density of 0.71 watts per cm3 (11.6 watts per inch3.

This reference design explained in detail in the Silanna Presentation:

  • Surpasses DOE multi-output power supply efficiency requirements 
  • Passes Critical Electromagnetic Interference (EMI) Requirements
  • Features a worst-case efficiency margin of 6%


Getting to Market Faster

Silanna offers an evaluation board to help designers get their applications up and running faster.


Evaluation board.
Evaluation board. Image courtesy of Silanna.


The company also offers an interactive, software-based application design tool, whose outputs include a full schematic, complete with a BOM.



  • USB-PD 
  • Battery Chargers for Mobile Devices
  • Fast Charging Power Adapters 
  • High-Efficiency Power Adapters 
  • High Power Density DC/DC Power Supplies