New Industry Products

20A to 25A Buck Converters to Power Next Generation Chipsets

January 17, 2019 by Scott McMahan

Alpha and Omega Semiconductor Limited introduced a new family of EZBuck™ regulators. The first two members of the family are the 20A, AOZ2367QI and the 25A, AOZ2368QI. The new devices offer a compact, efficient power converter solution for next-generation chipsets used in high-end TVs, servers, data storage systems, networking and other compact PC systems.

Next generation microprocessors and SoCs require more power to do high-speed calculation and to deliver more add-on functions to improve user experiences. Implementing much higher output power in a dc-dc converter frequently requires the use of several external components including high-current and low turn-on resistance MOSFETs.

That is where the new converters come in. The 20A, AOZ2367QI and the 25A, AOZ2368QI converters integrate the company's advanced MOSFET technology to power next-generation high-end systems. AOS says its unique packaging expertise also gives these converters better thermal management to ensure the system runs in a stable and robust environment.

The new devices feature all the integration advantages of the EZBuck family of products. The new high-current regulator combines the company's MOSFET technology with advanced packaging technology for high-performance and high-converting efficiency dc-dc regulators in a compact footprint.

The company says its performance MOSFETs enable high efficiency over the entire load range with low on resistance in the range of 1mΩ to 4mΩ and light-load efficiency that gets an additional increase with an optional pulse frequency mode (PFM).

The 20A and 25A devices are all available in a footprint compatible QFN 5 x 5mm package that gives designers an easy upgrade path as power requirements increase.

The devices operate over a wide input voltage range of 4.5V to 24V with output voltages adjustable down to 0.6V. According to Alpha and Omega Semiconductor, the proprietary COT architecture provides ultra-fast load transient response performance and produces a stable and low voltage ripple operation with small size ceramic capacitors.

A proprietary constant on-time PWM control with input feed-forward results in ultra-fast transient response while maintaining relatively constant switching frequency over the entire input voltage range. A low 80ns minimum ontime enables very low output voltages at ultra-high operating frequencies.

Integrated AC ripple injection enables all-ceramic low ESR output filter capacitors and smaller PCB footprint with no external components needed. Selectable PFM mode optimizes light load efficiency while forced PWM mode maintains constant frequency for lower harmonic noise.

The devices feature multiple protection functions such as VCC under-voltage lockout, cycle-by-cycle current limit,

output over-voltage protection, short-circuit protection, and thermal shutdown.

Competing solutions need several external components when using all ceramic capacitors and have to generate a larger output ripple voltage to stabilize the circuit.

Additionally, the input feed forward feature offers a constant switching frequency over the full input voltage range, which further eases noise concerns for designers.

Features of Both Converters Models

  • Wide input voltage range - 4.5V to 24V
  • Output voltage adjustable down to 0.6V (±1.0%)
  • Low RDS(ON) internal NFETs
  • Constant On-Time with input feed-forward
  • Programmable on-time up to 2.6µs and down to 80ns
  • Programmable switching frequency range: 32kHz to 1MHz (for 12VIN to 1VOUT)
  • Selectable PFM or forced PWM light load operation
  • Ceramic capacitor stable
  • Adjustable soft start
  • Power Good output
  • Integrated bootstrap diode
  • Cycle-by-cycle current limit
  • Short-circuit protection
  • Thermal shutdown
  • Thermally enhanced 5mm x 5mm QFN_28L package

"The new family of high-current EZBuck regulators offers maximum power to the user by allowing not only a pin-compatible footprint from 20A to 25A for easy upgrade, but also minimizes the overall design space with less external components to achieve excellent power density. This makes the design of complex distributed power systems with higher power far simpler and easier," said Wayne Lee, Power IC Marketing at AOS.

Pricing and Availability

The AOZ2367QI and AOZ2368QI are immediately available in production quantities with a lead-time of 12 weeks. The unit price for 1,000 pieces is $2.529 for the AOZ2367QI and $2.948 for the AOZ2368QI.