Product Overview
California Micro Devices introduces the CM1425, a four-channel electromagnetic interference (EMI) filter array with electrostatic discharge (ESD) protection for data lines that connect keypad modules, baseband chipsets and I/O data ports and busses in mobile devices such as wireless handsets and PDAs. The CM1425 is a pin-to-pin replacement for California Micro Devices’ CSPRC032A, offering superior filtering performance and a higher level of ESD protection. California Micro Devices’ proprietary Centurion™ advanced zener process ensures a lower equivalent series resistance (ESR) and 50% less capacitance, resulting in improved high frequency attenuation characteristics.

The CM1425 is manufactured as a 9-bump chip scale packaged (CSP) device and is available with OptiGuard™ coating for greater durability. The CM1424 is also available with preformed eutectic (63Sn/37Pb composition) or lead-free (96.8Sn/2.6Ag/0.6Cu composition) 0.30mm solder spheres for attachment.

Product Features
The CM1425 is designed for EMI suppression on signal interfaces present in today's technology products. It provides greater than 30dB of attenuation over the 800MHz to 2.7GHz carrier frequency range, and with a pi style (C-R-C) low pass filter architecture, the CM1425 has a faster roll-off while maintaining a cut-off frequency of 86MHz. The improved attenuation is due to a reduced filter capacitance value of 20pF, more that 50% lower than competing solutions.

In addition to its strong filter performance, the CM1425 also provides a high level of ESD protection of ±15kV contact discharge on each channel, far exceeding the IEC61000-4-2 Level 4 specification used for EMC regulatory compliance.

The CM1425 replaces 20 discrete components, therefore providing significant board space savings and total cost reduction. Referencing iSuppli Corporation's passive cost model, the CM1425 can result in a cost savings of greater that 50% when compared to a discrete passive solution. Manufactured in a tiny, 2.47mm X 0.97mm low profile Chip Scale Package (CSP), the CM1425 also offers up to 89% board space savings. In addition, the CM1425 pinout was configured to facilitate flow-through routing, simplifying PCB layout and optimizing filter performance. Chip scale packaging, by nature, also offers a very low inductance ground return path, further enhancing filter and ESD protection performance when compared to discrete EMI and ESD solutions.

Features of the CM1425 include:

• Four channels of EMI filtering with ESD protection
• Centurion™ process technology for effective EMI filter performance and robust ESD protection
• ±15kV ESD protection (IEC 61000-4-2, contact discharge)
• ±30kV ESD protection (HBM)
• Greater than 30dB of attenuation at 1GHz to reject unwanted high frequency signals
• Up to 89% board space savings versus discrete implementations
• Space-saving, low profile CSP form factor ideal for mobile applications
• Optional OptiGuard™ coating for improved reliability at assembly
• Optional lead free finishing

Product Applications
The CM1425 family of devices is suitable for a number of mobile handset applications. These include:

• EMI suppression on data lines typically found between wireless and baseband chipsets and at the keypad module data interface to the baseband processor
• Keypad I/O lines typically routed through flex cables between a keypad and the main system PCB, typically suceptible to ESD strikes
• EMI filtering for LCD and chip-to-chip data lines
• EMI filtering for data ports in cell phones, PDAs or notebook computers

Sampling, Pricing and Availability
The CM1425 is currently sampling, and pricing starts at $0.40 each in 1,000 units. Volume production is scheduled for June 2004. Lead free packaging and OptiGuard™ coated versions are available.