In some embodiments, a device detection circuit for detecting whether a device
is coupled to a differential link, a transmitter (e.g., a transceiver) including
such a circuit, and a system including such a transmitter. Preferably, the device
detection circuit includes two branches (each branch including a switch), a current
source that causes current to flow through either branch, or to be shared by both
branches, depending on the state of each switch, and a voltage swing detector configured
to detect the voltage between a node (of one branch) and a node (of the other branch)
during a device detection operation. In other embodiments, the invention is a device
(e.g., a receiver) including a differential termination that can be coupled to
a differential link, and an electrical overstress protection circuit coupled to
the termination and configured to protect the device against electrical stress
during a hot plug event.