Input stages for opto-emulators

A circuit comprising:

• a current mirror having first and second outputs;
• oscillator circuitry including:
• a first transistor having a first terminal coupled to the first output of the current mirror, having a second terminal, and having a control terminal;
• and
• a second transistor having a first terminal coupled to the first output of the current mirror, having a second terminal coupled to the control terminal and the second terminal of the first transistor, and having a control terminal coupled to the second terminals of the first and second transistors;
• and
• oscillator disable circuitry having a first terminal coupled to the second terminal of the current mirror.

A circuit comprising:

• a transmitter circuit having:
• a current mirror circuit including a first output, a second output, and a third output;
• an oscillator circuit having an input coupled to the first output of the current mirror circuit, a first output, and a second output;
• and
• current shunt circuitry having a terminal coupled to the second output of the current mirror circuit;
• and
• oscillator disable circuitry having a first terminal coupled to the third output of the current mirror circuit;
• a receiver circuit having first and second inputs;
• and
• an isolation circuit having first and second terminals coupled to the first and second outputs of the oscillator circuit and third and fourth terminals coupled to the first and second inputs of the receiver circuit.