Low-voltage differential signaling (LVDS) is a widely used differential signaling technology for high-speed digital-signal interconnections. In many applications, the LVDS receiver needs a fail-safe function to avoid an uncertain output state when the input is connected improperly. In this application note, we will examine the circuit design and performance characteristics of three popular fail-safe functions. Comparative analysis of circuit designs will guide readers in the use of fail-safe circuits for high-speed data-transfer applications.