|
|
|
 |
|
issue: April 2008 APPLIANCE Magazine
Technology Report
Joint Power |
 Printable format
 Email this Article
 Search
 |
|
Two technologies team up to give appliance engineers power handling capability in a small form factor. |
Alpha & Omega Semiconductor Inc. of Sunnyvale, CA, U.S. has found a way to squeeze power into a compact DFN3x3EP MOSFET package. According to David Grey, director of marketing, the patented process combines MOSFET active area and a Schottky diode monolithically into a single chip. “The common approach is to use two discrete die,” he explains. “With a package this small, it is difficult to achieve good Rds(on) performance with this construction technique. Small geometry MOSFET process is the key to achieve a low enough Rds(on) using a small die size.”
The company claims to be the first to integrate Schottky diode (SRFET) technology into a 3 × 3-mm package. “A Schottky diode in parallel with the low-side MOSFET gives several advantages that improve efficiency and reduce transient voltage spikes,” Grey says. “Combining both functions into one die further enhances these advantages with the added benefit of lower material and assembly costs.”
|
The company says its new advanced MOSFETs are optimized to provide high efficiency and high power-density solutions, while reducing heat dissipation and using less space.
|
The SRFET device’s Schottky body diode features a low forward voltage drop of 0.4 V that reduces power losses and a soft-recovery characteristic that reduces ringing and associated EMI. In addition, designers can achieve higher current and power density as a result of the package’s exposed copper-lead frame, which permits efficient heat transfer into the printed circuit board. And while the package is said to use only one-third the board area of an SO-8 device, it maintains the same 60°C/W thermal performance.
Because of its small form factor, the new AON740x product family is ideal for space-constrained applications requiring high-efficiency dc-dc conversion, such as notebook and desktop PCs, set-top boxes, and high-end appliances such as washing machines and refrigerators that have more-advanced displays. “These MOSFETs are truly general-purpose, high-performance transistors,” Grey tells APPLIANCE. “They are typically used in dc-dc convertor circuits to generate voltages required by the controlling electronics. Therefore, any motherboard in a desktop or notebook computer or any control board in a set-top box or high-end home appliance is likely to need some form of electronic power management.”
Grey also says that implementing the devices into existing product designs is fairly straightforward. “This 3 × 3 package is already used in the industry, so in some cases, we can second-source an existing device and provide an improvement in performance or cost-effectiveness,” he says. “Failing that, a PCB layout change would be required to convert from the popular SO-8 or another package.”
www.aosmd.com
|
|
|
|
