How TVS Diodes work

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In virtually every electronic device, designers need to protect against ESD, EFT, surge and other overvoltage threats . TVS diodes provide a fast response, high withstand capability, long life, and low capacitance, making them ideal for protecting sensitive ICs with high speed interfaces. A TVS diode is a p-n junction diode that is placed in parallel with the circuit to be protected. TVS diodes have three key voltage ratings: reverse standoff voltage, breakdown voltage, and clamping voltage. During normal operation, with the circuit at or below the diode’s reverse standoff voltage, the diode does not conduct, and its low leakage current and low capacitance make it virtually transparent to the circuit. When an overvoltage event occurs and voltage begins to rise in the circuit, the TVS diode enters breakdown and shunts the incoming current to ground, keeping the voltage seen by the circuit at the diode’s clamping voltage and preventing damage. The construction and operating characteristics of TVS diodes provide designers many performance advantages over other protection devices. A TVS diode is tuned to combine a fast response time with low breakdown and clamping voltages relative to its reverse standoff voltage, meaning transients can be clamped quicker and closer to the normal operating voltage. The diodes are manufactured with large area p-n junctions that can repeatedly carry high currents and withstand high transient voltages, ensuring reliable operation and longer life. This construction also results in low capacitance, which allows TVS diodes to be used on high speed data lines without distorting the signal. Eaton offers a wide variety of TVS diodes to protect against ESD, EFT, and surge events, from tiny chip size packages and arrays that minimize PCB area to larger surface mount and radial devices with higher reverse standoff voltages and current handling ratings in the tens of thousands of amps.