Dynamic input match correction in RF low noise amplifiers

The input match of low noise amplifiers can degrade significantly due to process faults and the parasitic package inductances at its input pad. These inductances have wide tolerances and are difficult to co-design for. This paper presents a self-correction methodology that will go beyond BIST systems by ascertaining the input match frequency and dynamically re-aligning it, thus rendering the input match fault and package tolerant. The proposed two-tonal approach depends only on the difference of two signals that pass through the same sensing circuitry. Consequently, it is inherently insensitive to process, power supply and temperature variations. Coupled with the fact that the majority of the signal processing occurs in the baseband/DC domain, complexity and precision demands are highly lenient. We present simple, low-precision circuitry designed in IBM 0.25 μm CMOS RF process with low power and real-estate overheads, no DSP cores or processors and fast correction times of less than 30 μs. To the authors´ knowledge, this paper represents the first ever attempt at self correction of integrated RF front-end circuitry.