Design of a 4.2–5.4 GHz differential LC VCO using 0.35 μm SiGe BiCMOS technology for IEEE 802.11a applications

✍ Scribed by Onur Esame; Ibrahim Tekin; Ayhan Bozkurt; Yasar Gurbuz

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 452 KB
• Volume: 17
• Category: Article
• ISSN: 1096-4290
• DOI: 10.1002/mmce.20218

✦ Synopsis

In this paper, a 4.2-5.4 GHz, ÀGm LC voltage controlled oscillator (VCO) for IEEE 802.11a standard is presented. The circuit is designed with AMS 0.35 lm SiGe BiCMOS process that includes high-speed SiGe Heterojunction Bipolar Transistors (HBTs). According to post-layout simulation results, phase noise is À110.7 dBc/Hz at 1 MHz offset from 5.4 GHz carrier frequency and À113.4 dBc/Hz from 4.2 GHz carrier frequency. A linear, 1200 MHz tuning range is obtained from the simulations, utilizing accumulation-mode varactors. Phase noise was also found to be relatively low because of taking advantage of differential tuning concept. Output power of the fundamental frequency changes between 4.8 dBm and 5.5 dBm depending on the tuning voltage. Based on the simulation results, the circuit draws 2 mA without buffers and 14.5 mA from 2.5 V supply including buffer circuits leading to a total power dissipation of 36.25 mW. The circuit layout occupies an area of 0.6 mm 2 on Si substrate, including DC and RF pads. V