Input-output (i/o) circuit supporting multiple i/o logic-level swings

Abstract

An integrated circuit (IC) includes an input/output (I/O) circuit supporting high-speed operation and multiple I/O logic-level swings. The I/O circuit includes a first output signal chain to generate outputs with a first logic level swing, and a second output signal chain to generate outputs with a second logic level swing. The outputs of the first output signal chain and the second output signal chain are connected to a same output pad of the IC. Transistors in the first output signal chain and the second output signal chain are fabricated using corresponding gate oxide characteristics. The second output signal chain includes protection circuitry to prevent transistors in the second output signal chain from being subjected to voltage stresses beyond a safe limit. An input circuit in the I/O circuit similarly includes multiple input signal chains to enable reception of input signals of different logic-level swings from a same input pad.