SLLS983J June 2009 – September 2019 ISO1050
The supply pins have undervoltage detection that places the device in protected or fail-safe mode. This protects the bus during an undervoltage event on VCC1 or VCC2 supply pins. If the bus-side power supply VCC2 is lower than about 2.7 V, the power shutdown circuits in the ISO1050 will disable the transceiver to prevent false transmissions due to an unstable supply. If VCC1 is still active when this occurs, the receiver output (RXD) will go to a fail-safe HIGH (recessive) value in about 6 microseconds.
|VCC1||VCC2||DEVICE STATE||BUS OUTPUT||RXD|
|GOOD||GOOD||Functional||Per Device State and TXD||Mirrors Bus|
|BAD||GOOD||Protected||Recessive||High Impedance (3-state)|
|GOOD||BAD||Protected||High Impedance||Recessive (Fail-Safe High)|
After an undervoltage condition is cleared and the supplies have returned to valid levels, the device typically resumes normal operation in 300 µs