DC/DC buck converter offers stackability for improved size and thermal performance

By Gina Roos, editor-in-chief

Texas Instruments (TI) has launched a new 40-A SWIFT DC/DC buck converter , claiming first-of-its-kind stackability of up to four integrated circuits (ICs) for maximized power density in high-current FPGA and processor power supplies. The TPS546D24A  PMBus buck converter can deliver up to 160 A of output current at an 85°C ambient temperature, which is 4× more current than competing power ICs, said TI.

The TPS546D24A also claims the highest efficiency of any 40-A DC/DC converter, which allows engineers to reduce power loss by 1.5 W in applications such as high-performance data center and enterprise computing, medical, wireless infrastructure, and wired networking.

Thanks to its stackability, theTPS546D24A buck converter can reduce the power supply solution size while optimizing thermal performance, said TI. It comes with a PMBus interface that offers a selectable internal compensation network, eliminating as many as six external compensation components from the board and shrinking the overall power supply solution size by more than 10% (or 130 mm² ) for higher-current FPGA/application-specific ICs (ASICs) when compared to discrete multiphase controllers.

Other features include a thermal resistance of 8.1°C per watt and 13°C cooler operation than competing DC/DC converters , which helps improve reliability in electronics that operate in hot, harsh environments, including baseband units and automated test equipment.

The TPS546D24A offers a switching frequency of 1.5 MHz, enabling 40 A of current per IC while reducing inductance and capacitance by one-third compared to similar converters. However, high switching frequencies typically have a negative impact on efficiency, which TI mitigates by incorporating a 0.9-mΩ low-side MOSFET, achieving 3.5% higher efficiency than competing DC/DC buck converters. (See SoC power design: 3 steps to a thermally optimized power supply  for more information.)

The TPS546D24A  is available from TI and authorized distributors in a 5 × 7-mm, 40-pin quad flat no-lead (QFN) package. Pricing starts at $4.27 in 1,000-unit quantities. The TPS546D24AEVM  evaluation module is available on TI.com for $199. Pin-to-pin– and footprint-compatible, pre-production TPS546B24A  (20-A) and TPS546A24A  (10-A) DC/DC converters are available now, only from TI. Pricing starts at $3.25 and $2.49 in 1,000-unit quantities, respectively. Reference design is available here .