A current based self-test methodology for RF front-end circuits

This paper presents a critical step in the realization of a robust, low overhead, current-based Built-In Self-Test (BIST) scheme for RF front-end circuits. The proposed approach involves sampling the high frequency supply current drawn by the circuit under test (CUT) and using it to extract information about various performance metrics of the RF CUT. The technique has inherently high fault coverage and can handle soft faults, hard faults as well as concurrent faults because it shifts the emphasis from detecting individual faults, to quantifying all the significant performance specifications of the CUT. This work also presents the realization of an HF current monitor which is a critical component in the proposed architecture. The current monitor has then been interfaced with three standard RF front-end circuits; a Low noise amplifier, a Single Balanced Mixer and a Voltage controlled oscillator, while minimally impacting their performance. The extracted information has then been used to create a mapping between variations in CUT performance and the sensed current spectrum. The monitor circuit has been fabricated in the IBM 6 metal, RF CMOS process, with a gain of 24 db and bandwidth of 3.9 GHz.