Abstract: An isolation system includes a transmit die and a receive die coupled by an isolation channel. The transmit die receives diagnostic data at an input terminal and transmits the diagnostic data over an isolation channel to a receive die. The receive die supplies a signal from an internal node in the receive die identified by the diagnostic data to an output terminal of the receive die. Other diagnostic data received by the transmit die causes the transmit die to supply a signal from an internal node in the transmit die to a terminal of the transmit die.

Abstract: An integrated circuit includes an input terminal configured to receive an input signal, a reference voltage node configured to provide a control voltage, and a pass transistor comprising a first terminal coupled to a first node, a control terminal coupled to the reference voltage node, and a second terminal coupled to the input terminal. The control voltage has a control voltage level sufficient to allow a signal to pass from the second terminal to the first terminal. The pass transistor is configured to linearly transfer the input signal to the first node in response to a voltage level of the input signal being below a first voltage level and configured to transfer a voltage-limited version of the input signal to the first node in response to the voltage level being above the first voltage level. At most, a negligible DC current flows through the input terminal into the second terminal.