Eliminating ESD Threats in Automotive Applications

Most silicon ESD protection solutions on the market today are designed for consumer electronics, but ESD threats can also keep automotive electronics designers up at night. It’s not just “normal” ESD conditions that worry automotive electronics designers, other automotive-specific events are also a major cause of sleeplessness, such as short-to-battery (STB) conditions.

Automotive battery short circuits can occur during assembly, repair, or when the devices are used by consumers in their cars. During assembly and repair, disconnected or exposed battery wires can be connected to any interface, which can damage the ESD protection device. A typical example of a battery short circuit during consumer use is a USB cable dropped into the car cigarette lighter socket, bringing the battery line voltage into the interface line. The presence of a 12V battery network in the automotive environment itself puts an additional burden on the automotive ESD protection devices, as these devices need to deal with situations where someone intentionally or accidentally shorts these interfaces with the battery wires. Therefore, if the interface is subject to this battery short circuit condition in addition to the ESD threat, the 5V conventional breakdown ESD devices used primarily in consumer electronics are not suitable.

The automotive-grade ESD protection device developed by ON Semiconductor takes into account the stand-off voltage and current limiting capabilities, and can easily deal with battery short circuit and ground short circuit (STG) events. In addition to these features, the device can also meet the needs of high-speed ESD protection, such as low insertion loss, high bandwidth and ultra-low capacitance, which are critical to signal integrity.

ESD protection devices such as the SZESD7361 , SZESD7462 , SZESD7102 , and SZESD1L001 have a minimum breakdown voltage of 16 V and can withstand automotive battery short-circuit conditions with battery voltages as low as 9 V and as high as 16 V. These devices not only provide low clamping ESD protection, but also have ultra-low capacitance and can operate in the GHz frequency range.

Devices such as the NIV1161 and NIV2161 have the same ESD protection silicon as the previous devices, while integrating small signal MOSFETs for current limiting, providing short-to-battery and short-to-ground protection for SoCs. These integrated MOSFETs have low Rds(on) and are suitable for applications with high data rates of Gigabits per second.