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25A Step-Down Regulator Breaks the Size Barrier: Fits in Tiny 8mm x 8mm TQFN

25A, Wide-Input Step-Down Regulator with Internal MOSFETs

Note to Editor: The MAX8655 is a highly integrated, 25A step-down regulator packaged in a tiny 8mm x 8mm TQFN, the industry's smallest footprint for such a powerful controller. The MAX8655 does not compromise any power or control features to fit into such a small package. By integrating discrete MOSFETs, the MAX8655 not only reduces space, but also dramatically lowers the generated EMI and virtually assures first-pass design. The MAX8655 is ideal for any application where space, power, and versatility are major concerns. Typical applications are high-end, power-intensive products such as server, telecom, and datacom equipment, as well as space-sensitive products like notebooks and flat-panel displays.

SUNNYVALE, CA—January 17, 2008—Maxim Integrated Products (Pink Sheets: MXIM) introduces the MAX8655, the first switching, step-down regulator to incorporate the MOSFETs and to shrink regulator packaging into the industry's smallest footprint—an 8mm x 8mm x 0.8mm (height) TQFN. This device provides output currents of up to 25A. A wide 4.5V to 25V input-voltage range allows for internal bus architecture (IBA) applications, where input voltage can have a two-to-one variation. A breakthrough in power density, output current, and size, the MAX8655 is ideal for any application in which space, power, and versatility are crucial.

The Problem of Power Density vs. Board Space

Today's complex boards in server, datacom, and telecom applications, for example, must squeeze more voltages into ever-smaller spaces. Increasing the number of power supplies on the board requires a commensurate increase in the power density. To compound the situation, while power management is critical to the integrity of any design, it is always the last problem to be solved. Designers, therefore, usually struggle with too little board space remaining and little or no time for revisiting the design.

Given this typical dilemma, designers traditionally turn to discrete solutions for power management. However, discrete solutions pose their own problems. Board size is much larger when using discrete components. Board trace inductance is also a common problem that leads to undesired EMI and stress on the semiconductor devices, typically forcing second and third passes before a design is successful.

Resolving the Power-to-Size Challenge

It is crucial that power management be small and versatile within today's power-hungry applications. Maxim's new proprietary PowerMind™ products, which include the new MAX8655 regulator, solve the space constraint issue and offer both versatility and simplicity of use.

Though packaged in a tiny TQFN, the MAX8655 does not compromise control features. Built-in MOSFETs incorporate all the critical inductances and eliminate undesired parasitic board inductances. By integrating discrete MOSFETs, the MAX8655 not only reduces space, but also dramatically lowers the generated EMI and virtually assures first-pass design.

Peak current-mode control at up to 1.2MHz switching simplifies compensation, allows for all types of output capacitors, and inherently provides feed-forward for optimum line regulation. Together with this peak current-mode-control topology, accurate current sensing enables paralleling in multiphase fashion. As a result, higher output currents are achieved and smaller output-filter components are required.

Designed with powerful programmable capabilities, the MAX8655 is highly flexible and versatile. Programmable features include slope compensation, OVP threshold, short-circuit protection, frequencies, and current limit (either latchoff or current fold-back with autorecovery overcurrent protection). Sync input/output and thermal protection are standard features that assure safe operation under all conditions.

The MAX8655 Advantage Summary

The MAX8655 regulator is an important industry innovation because it combines advanced packaging and process technologies, high frequency, and scalability with all standard power-management features, and it completely removes the need for discrete solutions.

When power management's allocated space is small and fixed, the MAX8655's tiny TQFN footprint is easy to accommodate. With the critical inductances built into the part and simple layout to follow, any engineer can drop the MAX8655 on his board and be much more confident of getting first-pass success. This device will definitely save design time, especially at those critical last stages of design.

The MAX8655 is versatile and powerful for high-end applications such as servers, telecom, and datacom equipment. Where a small footprint and robust power are so important, the MAX8655 will appeal. Typical applications in this category include space-sensitive notebook PCs and flat-panel TVs, and also industrial applications where the wide input range can be important.

Maxim's new PowerMind products like the MAX8655 allow the designer to focus on getting the rest of the design working, assured that there is already available a small and simple solution for the power management. An evaluation kit will soon be available. Pricing for the MAX8655 starts at $3.78 (10,000-up, FOB USA).

Maxim Integrated Products, a two billion dollar company, designs and manufactures ICs for analog and mixed-signal applications. The company's broad portfolio of 27 product lines is among the industry's deepest, with over 5400 products.