A Low-Noise Injection-Locked Ring Oscillator for biomedical implants applications

Abstract

This paper presents an Injection Locked Ring Oscillator (ILRO) for use in biomedical implants applications. A pulse injection locking method has been desired for ring oscillator performance enhancement and phase noise cancellation. In addition, the frequency is controlled independently of the biasing circuit using an inversion mode MOS voltage controlled capacitor (varactor).Designed in a 0.18-μm CMOS, this ILRO works inthe ISM band of 902–928 GHz and consumes a lowpower of 4.62 mW under 1.8V power supply. The phase noise of -121.6dBc /Hz at 1MHzoffset frequency was obtained at 76 MHz inputinjection pulse.The proposed circuit can achieve a FoM of -174.19 dBc/Hz.