A Temperature‐Compensated Frequency‐Locked Loop‐Based RC Oscillator Featuring Single‐Type Resistor Geometry Manipulation

ABSTRACT This paper presents a temperature‐compensated frequency‐locked loop‐based closed‐loop oscillator featuring a novel process‐scalable RC network composed of only a single type of resistor. In the proposed architecture, the dependence between the geometric parameters and temperature coefficient of a single‐type resistor is exploited to implement a temperature‐compensated RC network. A leakage‐reduced analog‐T switch is introduced to improve the frequency stability under high temperatures. In addition, a ping‐pong switched‐capacitor resistor is proposed to relax the trade‐off between switching‐induced voltage ripple and the size of the filtering capacitor. When fabricated in a 28 nm CMOS process, the prototype RC oscillator achieves a frequency error of 188.5 ppm/°C over the range −20°C to 100°C after compensation and an RMS period jitter of 9.51 . The power efficiency is 0.89 μW/MHz.