Data lines connecting electronic systems need to be protected against various ESD pulses to ensure signal integrity. These transients are mainly caused by human interaction with the electronics systems (controls, buttons and ports) or by interaction between systems due to different charge build up. These transients are typically bidirectional and very fast.
When used in communication bus designs, Multilayer varistors (MLVs) can save approximately 90% of the board area involved with diode/EMC cap solutions. In addition, MLVs offer a FIT rate <0.1, an ability to be used at temperatures up to 175°C and a fast turn on time.
The high-performance sensor systems in modern automobiles (particularly electric and self-driving vehicles) has created immense pressure to develop automotive local area networking (LAN) solutions that offer high bandwidth, low latency, and low cost. Wired Ethernet has taken center stage in this quest. In addition to data transfer, the same twisted pair is capable of providing power to sensor subsystems using power over Ethernet (PoE) techniques. Most importantly, automotive single-pair Ethernet accomplishes this while still adhering to robust EMI and EMC requirements.
When it comes to protecting electrical equipment from high voltage transients, MLVs are one of the most popular choices. These devices exhibit a reduction in their intrinsic resistance at high voltages, effectively clamping the voltage spike and dissipating the energy as heat. When protecting integrated circuits on high-speed data lines, such as an automotive Ethernet PHY, capacitance becomes the most critical parameter because it can directly affect the data waveform.
AVX offers a wide variety of varistors that are 100BASE-T1 and 1000BASE-T1 OPEN Alliance compliant to support these designs. In particular, AVX's Antenna PowerGuard varistors are perfectly suited to protect Ethernet circuits from ESD.