A Robust 130nm-CMOS Built-In Current Sensor Dedicated to RF Applications

An otherwise well-known ratiometric built-in current sensor (BICS) dedicated to monitor the current of analog and mixed-signal building blocks highlights a dependency with regards to technology discrepancy. In this paper we present a design methodology that allows to dramatically reduce the dependency, yielding to a new version of this BICS. Taking advantage of a 130 nm VLSI CMOS technology, the BICS proposed has a peak-to-peak dispersion lower than 10 % of its output full-scale range. It makes it more suitable to implement the test functionality while maintaining the initial BICS intrinsic performances. The built-in self test methodology is illustrated by monitoring the supply current of a low-noise amplifier (LNA). Measurements confirm the BICS´s low sensitivity to process variations and its transparency relative to the circuit under test (CUT)