rlcZONE Products for the week of October 8, 2007

Alpha & Omega Semiconductor Says…

Integrated EMI Filters for Next-Generation Cellular Handheld Devices
EMI Filters Leverage [TVS] 2 Technology for Advanced and Optimized Filter Attenuation

Alpha & Omega Semiconductor, Inc. (AOS), a leading developer of advanced power semiconductor solutions, announced new multi-line EMI Filters designed and optimized to suppress unwanted EMI/RFI signals and provide ESD protection for next generation cellular handheld devices.

The AOZ8011 and AOZ8014 leverage the company's proprietary [TVS]2 technology. The advanced [TVS]2 process utilizes a Trench Vertical Structure to optimize Transient Voltage Suppression and EMI filtering of high speed data lines.

"These new multi-line EMI filters with integrated ESD protection offer advanced and optimized filter attenuation performance from 800 MHz to 3.0 GHz over the full display operating range, improving overall device reliability and user experience," said Wayne Eng, Director of Product Marketing at AOS. "This introduction exemplifies how AOS continues to expand its device protection solutions with leadership products."

"The handset market for smart and feature phones are growing from 76% of the total market in 2006 to 1.14 billion or 85% of the market in 2010," said Shyam Nagrani, Principal Analyst at iSuppli Corp. "As higher resolution displays, more capable cameras, more A/V features and more I/O get integrated in to the handset, the need for better EMI filtering and ESD protection becomes more important. AOS's new integrated EMI filter solutions address this huge, growing market need."

Product Highlights
The AOZ8011 and AOZ8014 protect 8 and 4 lines respectively, providing suppression of unwanted EMI/RFI signals and ESD protection of data lines in LCD displays, camera and I/O interfaces in handheld devices such as cell phones and PDA smart phones.

The filter performance is rated at -25dB attenuation from 800MHz to 3.0GHZ over the full display operating range and features industry-leading clamping voltage performance. The device's low channel clamping voltage of 8.5V maximum at 12A peak pulse provides superior protection to sensitive IC components. Both devices are rated to provide ESD protection of +/-17kV for contact and +/-17kV for air discharge.

The AOZ8011 comes in a small footprint 1.6 x 4.0 mm DFN package and AOZ8014 in a 2 x 2 mm DFN package. These small packages are ideal for portable handheld applications where board space is limited.

EN-Genius Says…

Alpha & Omega Semiconductor multi-line filters are the kinds of devices just about anyone crafting a sensitive circuit ought to design-in. Although they're deceptively simple arrays combining avalanche clamping diodes and passive RC filters, AOS' new AOZ8011DI and AOZ8014DI devices fill the bill by giving you a single multi-function low-leakage component that can be readily specified and installed in any 5-V (or lower voltage) circuit. Competing Zener-like devices, such as those from STMicro, ON Semi, and others, typically only offer clamping diode protection.

AOS miniature DFN (dual flat no-lead) packages also look like just the ticket for pick-and-place surface-mount assembly. Although diminutive, these lead-free RoHS-compliant (Restriction of Hazardous Substances) devices are hefty performers, able to heft 12-A pulses at very high ESD voltages. When you consider how small they are, that's extraordinary.

In addition to voltage-clamping elements, they operate as UHF RF filters, thanks to their built-in 100-Ω series resistors and 17-pF bypass caps. The combination of clamping diodes and tuned filters is unique. What's more (and not mentioned in the AOS release), both device types exceed the IEC (International Electrotechnical Commission) IEC-61000-4-2, Level 4 ESD immunity tests.

One limitation for both AOZ8011DI and AOZ8014DI devices is that all channels share a common ground pin. There may be applications where separate grounds would be optimum. Another limitation is the package's exposed ground pad. You must make provision on your circuit board layout to accommodate this pad. The package's eight or 16 pins are entirely dedicated to signal I/O; there are no ground pins per se.

The two EMI filters are in production with pricing for the AOZ8011DI and AOZ8014DI at $0.21 and $0.14 in 1000-piece lots, respectively.