The AM26LV32 is a quadruple differential line receiver that is designed to function properly when appropriately connected to active drivers. Applications do not always have ideal situations where all bits are being used, the receiver inputs are never left floating, and fault conditions do not exist. In actuality, most applications have the capability to either place the drivers in a high-impedance mode or power down the drivers altogether, and cables may be purposely (or inadvertently) disconnected, both of which lead to floating receiver inputs. Furthermore, even though measures are taken to avoid fault conditions like a short between the differential signals, this does occur. The AM26LV32 device has an internal fail-safe circuitry which prevents the device from putting an unknown voltage signal at the receiver outputs. In the following three cases, a high-state is produced at the respective output:

1. Open fail-safe: Unused input pins are left open. Do not tie unused pins to ground or any other voltage. Internal circuitry places the output in the high state.
2. 100-Ω terminated fail-safe: Disconnected cables, drivers in high-impedance state, or powered-down drivers does not cause the AM26LV32 to malfunction. The outputs remain in a high state under these conditions. When the drivers are either turned-off or placed into the high-impedance state, the receiver input may still be able to pick up noise due to the cable acting as an antenna. To avoid having a large differential voltage being generated, the use of twisted-pair cable induces the noise as a common-mode signal and is rejected.
3. Shorted fail-safe: Fault conditions that short the differential input pairs together does not cause incorrect data at the outputs. A differential voltage (V_ID) of 0 V forces a high state at the outputs. Shorted fail-safe, however, is not supported across the recommended common-mode input voltage (V_IC) range. An unwanted state can be induced to all outputs when an input is shorted and is biased with a voltage between −0.3 V and +5.5 V. The shorted fail-safe circuitry functions properly when an input is shorted, but with no external common-mode voltage applied.