New Industry Products

Alpha and Omega Semiconductor’s New SPS Family is Aimed at Multiphase Voltage Regulators

May 26, 2021 by Gary Elinoff

The AOZ527xQI series from Alpha and Omega Semiconductor (AOS) provides three different DC current levels for optimal multiphase voltage regulation.

The AOZ527xQI family of smart power stages SPS are geared for multiphase VR regulators powering the low-voltage GPUs and CPUs now common in graphics cards, gaming PCs/laptops, servers, AI applications, and networking equipment. 

The AOZ527x series. Image courtesy of AOS.
The AOZ527x series. Image courtesy of AOS.


The four members of the series variously operate from either 3 to 20VDC or 3 to 25VDC. They supply their low-voltage outputs at either 60, 70 or 90 amps, allowing tradeoffs for systems designers in both the number of phases they incorporate and in the amount of current per phase.


The Need

As per Peter Cheng, Sr. Director, Power IC Marketing at AOS, “The Smart Power Stage in the QFN 5 x 6 footprint has been an industry standard for a while. AOS’s approach of offering a family of devices for various performance levels and end applications makes our offering unique. For example, our AOZ5279QI can be used for gaming laptop applications being powered by a 20V adaptor, while, ourAOZ5277QI, AOZ5273QI, and AOZ5276QI offer multiple options in multiphase regulators used in add-in cards, servers, 5G and artificial intelligence.” 


Characteristics of the Series

The units provide a temperature monitoring (TMON) pin. Also a fault pin, TMON reports power stage temperature via an 8mV/°C analog voltage signal.

Typical application for the AOZ527xQI Series. Image courtesy of AOZ5277QI datasheet
Typical application for the AOZ527xQI Series. Image courtesy of AOZ5277QI datasheet


There is also a current monitoring (IMON) function that replaces the oft-employed inductor DC resistance (DCR) methodology. Through IMON, the expense of choosing the right type of inductor is eliminated, accuracy is improved, and no ancillary components need be added to the BOM.

The units are optimized for a switching speed of 1 MHz


Built In Versatility and Protection

The AOS SPSs provide the protection features the designers expect, such as over-temperature protection (OTP) and over-current protection (OCP). There is also pre-over-voltage protection and high-side FET source detect. Due to its versatile driver, AOZ527xQI series members are compatible with many of today’s popular multiphase controllers. Additionally the devices feature dynamic control of the OCP threshold and there is zero-cross detect (ZCD) for light load operation. 

The AOZ5279QI family members can support the momentary current spikes common in AI, GPU and server applications. Peak current capabilities are up to 150 amps for 10µs and 100 amps for 10µs.


Individual Series Members

Series members can work with the typical 12 VDC input ranges of AI and GPU add-in cards in addition to the 20 volts rails of gaming laptops. Detailed data sheets can be found by left clicking AOZ5273QI, AOZ5277QI or AOZ5279QI.


  DC Current Input Voltage Range Maximum Input Voltage
AOZ5273QI 70 amps 3 to 20 VDC 25 VDC
AOZ5276QI 90 amps 3 to 20 VDC 25 VDC
AOZ5277QI 60 amps 3 to 20 VDC 25 VDC
AOZ5279QI 60 amps 3 to 25 VDC 30 VDC



The series members are targeted at are designed for incorporation within multiphase VR regulators serving today’s expanding universe of high-performance power voltage applications.


Physical Considerations

  • Members of the AOZ527xQI series are available in an industry-standard 5mm x 6mm QFN package 
  • They operate over a junction temperature range of -40 to 125 °C