The TVS1801 is a bidirectional TVS with a symmetrical operating region. This allows for operation with positive and negative voltages, rather than just positive voltages like the unidirectional TVS1800. This allows for single chip protection for applications where the signal is expected to operate below 0 V or where there is a need to withstand a large common-mode voltage. In addition, in many cases, there is a system requirement to be able to withstand reverse wiring conditions, in many cases where a high voltage signal is accidentally applied to the system ground and a ground is accidentally applied to the input terminal. This causes a large reverse voltage on the TVS diode that it must be able to withstand. The TVS1801 is designed to not break down or see failures under reverse wiring conditions, for applications that must withstand these miswiring issues.