Wireless Systems Design

EMI Filter Arrays Stave Off Electrostatic Discharge

A series of four electromagnetic-interference (EMI) filter arrays vows to provide electrostatic-discharge (ESD) protection in thin DFN packages. These four-channel, six-channel, and eight-channel filters were specifically designed for the high-speed data interfaces in mobile phones. Compared to traditional chip-scale packages, they provide high performance and reliability in a drop-in replacement footprint (1.35 × 3 mm).

All of the filters come in a TDFN package to provide optimal filtering performance. Such performance boasts extremely low parasitic inductance and higher reliability in terms of handling and solderability. Additionally, the filters reduce board space by 40%. They replace up to 24 discrete components.

Each filter delivers superior S21 characteristics with extremely low parasitic inductance (10 pH to 20 pH) due to the TDFN-package groundpad. These devices are capable of attenuating unwanted signals over the RF band between 800 MHz and 2.9 GHz. Each device features an application-specific cutoff frequency (95 to 110 MHz), which is optimized for LCD-display and camera interfaces.

The NUF4402 is a low-capacitance, four-channel EMI filter. It was designed for filtering signals in LCD-display and camera interfaces with a maximum data rate of up to 54 Mbps per line. The NUF8401 is an eight-channel unit. They cost $0.25 and $0.44 each, respectively, in lots of 10,000. The NUF6401 is a six-channel EMI filter that can attenuate unwanted signals at 35 dB from 800 MHz to 2.7 GHz. The device sells for $0.33 each in lots of 10,000.

ON Semiconductor
5005 E. McDowell Rd., Phoenix, AZ 85008; (602) 244-6600, www.onsemi.com/tech.

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