California Micro Devices Premiers High-Frequency EMI Protection For PC Parallel Port

10/1/2002 - California Micro Devices announced that it has introduced the PACZIG1284, the first device to protect parallel ports against electro-magnetic interference (EMI) in PCs with frequencies from 100 MHz to 3 GHz. The new device also provides termination and protects parallel ports with the industry's highest level of electrostatic discharge (ESD) protection.

"These capabilities are critical for next-generation PCs," said Joe Salvador, director of marketing for computing products at California Micro Devices. "Filtering excessive EMI emissions is particularly critical. New high-frequency EMI sources, such as Bluetooth, 802.11 wireless LAN, IEEE1394 and USB 2.0, can couple to the parallel port, causing high-frequency emissions if not properly filtered. If you're a PC manufacturer, excessive EMI means that the FCC and other international regulatory agencies can ban your product from going to market."

The PACZIG1284 owes its capabilities to California Micro Devices' innovative Zero Inductance GroundTM (ZIGTM) technology. This technology connects the filters inside the PACZIG1284 directly to the PC motherboard through a metallic pad that protrudes through the bottom of the PACZIG1284 package, rather than through bond wires and ground pins, eliminating the inductance that limits other filtering solutions. The result is a filter that performs just as well at lower frequencies as previous solutions, but now also extends the filtering capability out to 3GHz.

Market Size: Parallel Port Still a Major PC Component
The market for PCs with parallel ports is expected to remain strong for the foreseeable future according to IDC. "The parallel port isn't gone yet," said Shane Rau, senior research analyst with IDC. "IDC estimates that nearly 300 million desktop and mobile PCs will ship with parallel ports between 2003 and 2006. Additional parallel ports will also ship in docking stations, printers, scanners, and other electronic equipment."

Advantages for OEMs are Advantages for End Users
California Micro Devices designed the PACZIG1284 to be backward compatible with its popular PACSZ1284, which is used by many of the industry's leading PC manufacturers. Like its predecessor, the PACZIG1284 integrates 69 discrete components into a single device, reducing board space and manufacturing costs. Both come in a 28-pin QSOP package and have identical pinouts. The PACZIG1284, however, has the addition of the ZIG pad on the bottom of the package. This allows OEMs to create a single layout, and use the lower-cost PACSZ1284 in systems that do not need high-frequency filtering, and painlessly upgrade to the PACZIG1284 for PCs requiring higher-frequency filtering.

California Micro Devices' Innovative Technology
Recognizing the need for a high-frequency filtering solution that works across a wide range of frequencies, California Micro Devices has developed ZIGTM technology for providing EMI filtering from 100 MHz to beyond 3 GHz. Previous EMI filtering solutions were limited in their filtering range by the parastic inductance of the filtering circuits. For example, in typical discrete RC filtering solutions, the parasitic series inductance present in commonly used chip ceramic capacitors limits their attenuation to a very narrow band of frequencies. This makes discretes inadequate if there are several problem frequencies that need filtering. Previous Application Specific Integrated Passives (ASIPTM) solutions from California Micro Devices improved on this capability by eliminating most of the capacitor inductance, providing a broader filtering range.

To achieve multi-GHz EMI filtering, it is necessary to even further reduce the series inductance of the filtering circuits. Using ZIGTM technology, this is achieved by minimizing the series inductance in the ground path from the internal filter ground to the ground plane of the printed circuit board. The silicon substrate, on which the filters are fabricated, is an internal ground plane for the filters. This silicon substrate is connected directly to the PCB ground plane through a metallic ZIGTM pad that protrudes through the bottom of the PACZIG1284 package, rather than through bond wires and ground pins. The result is a filter that performs well at lower frequencies as previous solutions, but now also extends the filtering capability to 3GHz.

Pricing and Availability
Two versions of the PACZIG1284 are currently sampling: The PACZIG1284-02, which has a pull-up resistor value of 2.2 K ohms and the PACZIG1284-04, which has a pull-up resistor value of 4.7 K ohms. Pricing for both versions is $0.71 at 10KU volumes. An evaluation board is also available.

About California Micro Devices
California Micro Devices Corporation is a leading supplier of application-specific analog semiconductor products for the mobile, computing, and high-brightness LED lighting markets. Key products include application -specific integrated passive (ASIPTM) devices and power management ICs as well as silicon submounts for high brightness LEDs.

ASIPTM is a trademark of California Micro Devices.

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