SRDA3.3-4 RailClamp® Low Capacitance TVS Arrays Semtech SRDA3.3-4 RailClamp® Low Capacitance TVS Arrays low capacitance ESD protection devices are ideal to protect sensitive components from overvoltage. These overvoltages include electrostatic discharge (ESD), electrical fast transients (EFT), and lightning surge. The SRDA3.3-4 Arrays feature characteristics for board level protection including fast response time, low operating and clamping voltage, and zero device degradation.