EMI filters and Application-Specific Integrated Products (ASIP)

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What is an EMI filter?

An electromagnetic interference (EMI) filter is used in electronic circuits to improve system immunity against unwanted external electromagnetic signals from neighboring circuits and to avoid emitting radiations that may disturb the same nearby circuits by cancelling unwanted frequencies (“noise”).

EMI noise can adversely affect useful dataline signals, possibly altering their functionality, either by coupling (capacitive or magnetic), by conduction (common or differential mode) or by electromagnetic field coupling (antenna effect).

Benefits of ST’s EMI filters and ASIP technology

The key benefit of ST’s EMI filters is to provide a monolithic integration of the required ESD protection at system-level (according to standard IEC 61000-4-2 Level 4 +8kV contact) along with a filter aimed to suppress the EMI noise on digital or analog communication lines for space-saving purposes:

  • For low-speed digital interfaces or analog application, ST provides EMI filters with integrated ESD protection, targeted to protect lines of memory cards, microphones, speakers, parallel displays, and keypads.
  • For high-speed datalines such as HDMI 2.0, HDMI 2.1, USB3.2, USB4.0, Display Port 2.0, SD-Card 4.2, MIPI DSI or CSI communications, ST’s Common Mode Filters with integrated ESD protection (ECMF) are tailored to reject a wide range of frequency bands (5G, LTE, 2.4 GHz Bluetooth, and 2.4 and 5 GHz Wi-Fi, to name a few.

For specific applications requiring more integration for space-saving and improved performance, ST has developed integrated circuits using its Application Specific Integrated Product (ASIP) technology that combines ESD protection at system level (IEC 61000-4-2) with discretes (R, L, C) and over voltage, over current protections, and other IPs such as low-drop-out regulators, deglitch filters and signal conditioning such as multiplexers and level translators among others. ST’s ASIPs reduce system size, complexity and cost while improving the Failures In Time (FIT) rate for increased longevity.

ST’s EMI Filters, ECMF and ASIPs for Automotive applications are qualified as per AEC-Q101 and are compliant with IEC 61000-4-2 and ISO 10605. They are useful in SerDes applications including FPD-link, GMSL, and MIPI DSI or CSI to avoid radiation in vehicle-to-everything (V2X) (5.9 GHz) and Global Navigation Satellite System (GPS, Glonass, BeiDou, Galileo, and IRNSS) frequencies.