Method and apparatus for detecting a tamper condition and isolating a circuit therefrom

DETAILED DESCRIPTION According to one embodiment of the invention, a system is disclosed for isolating a bond pad from the rest of the circuitry of a semiconductor chip in a manner that protects the chip from applied signals that are outside the normal operating range and which tamper with the operation of the system.
The system includes the use of a controllable switch for routing the signal from the bond pad to the circuit and a detector for detecting a tamper condition on the bond pad.
The detection of a tamper condition causes the detector to inform the microcontroller on the chip to, for example, terminate the operation in progress, perform a controlled system shutdown, disable pre-arranged functions, or record the fact that a tamper condition occurred.