A 60 GHz Frequency Synthesizer in 0.13 μm SiGe BiCMOS for Biomedical Implant Applications

This paper presents the design and implementation of a low-power fractional-N Phase-Locked Loop (PLL)-based frequency synthesizer fabricated in 130 nm BiCMOS technology for 60 GHz datalink applications. Driven by the semiconductor industry’s trend toward miniaturization, especially for implantable health monitoring systems, the PLL utilizes a push-push Colpitts voltage-controlled oscillator (VCO) that employs its second harmonic to achieve a 60 GHz output. The architecture integrates static and multi-modulus frequency dividers, a sigma-delta modulator, a phase/frequency detector, a charge pump, a loop filter, a built-in bandgap voltage reference (BGR), and a low-drop-out (LDO) regulator for optimal performance. Measurement results indicate the synthesizer operates within a frequency range of 59.3 GHz to 65 GHz while consuming only 140 mW from a single 1.5V DC supply. The PLL exhibits phase noise levels ranging from -88 dBc/Hz to -96 dBc/Hz at a 1 MHz offset across its frequency range. The proposed PLL design exhibits robust frequency stability and high integration capabilities, making it a viable solution for advanced biomedical sensors in health monitoring applications.