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The consequences of electrostatic discharge and other transient overvoltage events are too serious to ignore.
SUPPORTED BY UBIQUITOUS broadband access, the smart television has all but replaced the traditional TV. With a smart TV, high-definition digital content can be streamed and customized from the "cloud" onto any device connected to the Internet, or it can be written to a physical disk and played back on demand.
Smart TVs are television sets with integrated Internet capabilities that offer advanced computing ability and connectivity. To achieve versatility, a smart TV usually utilizes the latest generation of technology, including smaller, more functionally complex ICs.
That decrease in feature size and increase in circuit density leads to new challenges in electrostatic discharge (ESD) and cable-discharge events (CDEs). However, designers can use transient voltage suppression (TVS) ICs to develop protection schemes for the two most common and sensitive interfaces on smart TVs - the High Definition Multimedia Interface (HDMI) and Gigabit Ethernet.
HDMI ESD/CDE PROTECTION
HDMI has gained in popularity since its inception. It is widely adopted in consumer electronics to transfer high-definition digital content. But as a high-performance interface, HDMI can be extremely vulnerable to cable discharge from a hot-plug cable and ESD directly from the user.
To ensure proper functionality, HDMI-based systems must protect all potentially exposed interface signals and power pins to meet or exceed the electrical over-stress (EOS) specification of IEC 61000-4-2, Level 4 (±15 kV Air, ±8 kV Contact) without damage. Current HDMI silicon runs at 2.25 Gbits/s with 3.4 Gbits/s in the near future.
At such a high data rate, signal integrity and impedance requirements are given more focus than ever before, as put forth in the HDMI Compliance Test Specification (CTS). The HDMI CTS requires all HDMI sink devices to maintain the differential impedance of the high-speed lines at 100 Ω ±15%.
At a data rate of 3.4 Gbits/s, providing low-clamping voltage protection without adding excessive capacity loading is critical to design. To effectively arrest transient surge to low clamping voltage, more silicon area in the TVS diode is required. Increasing silicon die area comes with the cost of higher capacitance, though.
This tradeoff dynamic can be overcome by building a low-capacitance diode array around a surge-handling TVS diode, effectively lowering...