A 33-ppm/°C 240-nW 40-nm CMOS Wakeup Timer Based on a Bang-Bang Digital-Intensive Frequency-Locked-Loop for IoT Applications

This paper presents a wakeup timer in 40-nm CMOS for Internet-of-Things (IoT) applications based on a bang-bang Digital-intensive Frequency-Locked Loop (DFLL). A self-biased Σ Δ Digitally Controlled Oscillator (DCO) is locked to an RC time constant via a feedback loop consisting of a single-bit chopped comparator and a digital loop filter,...