Adaptable I/O pad circuit for multiple voltage units bus operation
A voltage adapter pad circuit is presented, the circuit is oriented to applications where multiple digital units working at different voltage levels communicate in a bus connection. The active receiver pad circuit adapts the voltage of its input stage to the power supply voltage levels of the active emitter unit equalising the noise margin of the communication bus. Additionally the logic levels of the bus input are adapted to the inner voltage of the receiving system.
integrated circuits digital communications cmos logic circuits