California Micro Devices Introduces Low Capacitance Praetorian® III EMI Filters for Wireless Handsets

(Product News, 31 Aug 2009)

California Micro Devices (NASDAQ:CAMD) announced the CM1457 family of inductor based electromagnetic interference (EMI) filters for mobile handsets. With traditional filter architectures, there is a tradeoff between low levels of capacitance -- which are necessary to achieve higher cutoff frequencies -- and reduced levels of filter attenuation. The CM1457, based on the advanced Praetorian III inductor based filter architecture, eliminates this tradeoff by providing superior attenuation and industry leading low capacitance. With a cutoff frequency of 400MHz and a steep rolloff, the CM1457 is ideal for filtering signal lines for high resolution displays and imagers in today's most advanced handsets, including those utilizing emerging 4G protocols such as LTE. The lower capacitance level of the CM1457 can also contribute to reduced system power consumption. The combination of these attributes makes the CM1457 an ideal solution for advanced multimedia and smart phone designs.
"By balancing the stringent filter performance requirements of high resolution displays and imagers with industry low levels of capacitance, the CM1457 delivers best of breed performance," said Kyle Baker, vice president of marketing for CMD. "And by utilizing the cost effective Praetorian III technology and chip scale (CSP) packaging, the CM1457 can be offered at prices comparable to current packaged RC EMI filters, thereby establishing a new benchmark for performance and customer value."
Today's latest mobile handset designs include many high bandwidth data interfaces to support popular consumer features such as high resolution LCDs (liquid crystal displays) and camera imagers. Handset designers are increasingly challenged to find EMI filter solutions that offer the high cutoff frequencies required in these applications to ensure excellent signal integrity and high levels of attenuation. Furthermore, to offset the additional power consumed in support of these popular multimedia capabilities and extend battery life, handset designers increasingly utilize advanced baseband processors that operate at lower operating voltages and feature lower output drive currents on display and imager interfaces. A lower capacitance EMI filter, when paired with these advanced CPUs, can contribute to reduced system power consumption.
The CM1457's Praetorian III EMI filter technology features a patent pending architecture offering high cutoff frequencies, very steep roll off and high levels of attenuation together with the world's lowest low total capacitance in an L-C type filter. The CM1457 provides -30dB attenuation starting at 700 MHz, and greater than -40dB attenuation from 800 MHz t0 3000 MHz. Typical cutoff frequency is 400MHz, allowing for excellent signal integrity for clock frequencies as high as 125 MHz.
Main Features
Key performance attributes of the CM1457's scalable pi-filter topology include:
-- Cutoff frequency of 400 MHz typical
-- Broad stop band from 700 MHz to 6 GHz
-- High levels of attenuation and robust ESD protection up to +/-15kV contact discharge, consistent with the IEC 61000-4-2 level 2 standard
-- Superior signal integrity with rise and fall times as low as 2ns
-- Minimal insertion loss (<1.5dB)
Maximum Layout and Placement Flexibility
The CM1457 family of solutions is available in packages providing 4, 6, and 8 channels, allowing easy PCB layout and routing flexibility to wireless handset designers. The table below shows the channel configuration options with their respective dimensions. They are offered in space saving 0.4mm pitch CSP packages.
CM1457 Product Family Summary
Product Number of Channels Package Dimensions and Footprint
CM1457-04CP 4 1.56 x 1.05 mm
CM1457-06CP 6 2.36 x 1.05 mm
CM1457-08CP 8 3.16 x 1.05 mm
The CM1457 series of products, all RoHS compliant, will sample in October and be available in mass production in Q4 2009. Pricing ranges from $0.10 and $0.20 each at 1,000 units depending on channel configuration.