SMAJ120ATR Circuit Protection

SMAJ120ATR is an advanced and low capacitance transient voltage suppressor (TVS) diode developed specifically for the protection of high speed data lines such as USB, IEEE 1394, and Telecom circuits, as well as consumer electronics against electrostatic discharge (ESD). Its active clamp topology significantly lowers its stand-off voltage while providing superior performance at frequencies up to 4GHz. Additionally, its low reverse leakage current helps to minimize current flow during ESD events.The SMAJ120ATR is a high power surface mount device consisting of a silicon NPN avalanche diode and two series connected N-channel Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), in a highly compact 8-lead “butterfly” SMD package. The diode is designed to be used in high-speed circuit line protection applications as a transient voltage suppressor diode. The MOSFETs are used together in an active clamp configuration to reduce the leakage current and reduce the output voltage.The SMAJ120ATR is designed specifically for protection of data lines, such as USB, IEEE 1394, and Telecom, as well as consumer electronics from ESD, Electro-Magnetic Interference (EMI), and over-voltage surges. The device has a maximum working voltage of 120V, a stand-off voltage rating of 6V, a peak pulse power (PDP) rating of 350W, and a maximum capacitance (Cd) rating of 7pF. The typical response time is 3.8ns and the typical leakage current is 0.3mA.The SMAJ120ATR works by shooting off high voltage data lines at a short duty cycle with low dV/dt to prevent over-voltage surges as well as ESD events from damaging sensitive electronics. As the voltage on the data lines increases, the MOSFETs in the active clamp configuration increase the parasitic capacitance of the device, allowing for a faster transient response, as well as reducing the leakage current. The SMAJ120ATR also has a built in oscillator that provides a rapid cut off time when there is a voltage surge on the data line.In addition, the SMAJ120ATR offers excellent waveform performance in terms of capacitance, ESD protection, and EMI shielding. The device has an integrated protection diode that helps to prevent over spikes on the data line, and it is rated for continuous operation up to 120V. The SMAJ120ATR has a low leakage current which can help keep FET drain currents low, and reduce power dissipation in the device during normal operation.In conclusion, the SMAJ120ATR is an ideal device for data line protection applications, providing superior performance, low capacitance, fast response, and robust surge protection. It is a reliable and cost-effective solution for line protection in applications such as USB, IEEE 1394, and Telecom circuits, as well as consumer electronics.

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