Defect-oriented non-intrusive RF test using on-chip temperature sensors

We present a built-in, defect-oriented test approach for RF circuits that is based on thermal monitoring. A defect will change the power dissipation of the circuit under test from its expected range of values which, in turn, will induce a change in the expected temperature in the substrate near the circuit. Thus, an on-chip temperature sensor that monitors the temperature near the circuit can reveal the existence of the defect. This test approach has the key advantage of being non-intrusive and transparent to the design since the temperature sensor is not electrically connected to the circuit. We discuss the basics of thermal monitoring, the design of the temperature sensor, as well as the test scheme. The technique is demonstrated on fabricated chips where a temperature sensor is employed to monitor an RF low noise amplifier.