Low Phase Noise and Wide Tuning Range VCO Using the MOS Differential Amplifier with Active Load

Cher-Shiung Tsai,Ming-Shin Lin,Kwang-Jow Gan

doi:10.4236/cs.2012.34043

Abstract

We demonstrate the design of a novel voltage-controlled oscillator (VCO), which is based on a metal-oxide-semiconductor field-effect transistor (MOS) differential amplifier with active load. This VCO achieves low phase noise and wide tuning range. The phase noise is –120 dBc/Hz at 600 KHz offset from a 1.216 GHz carrier frequency. This value is comparable to that of a LC-based integrated oscillator. The operating frequency can be tuned from 117 MHz to 1.216 GHz with the supply voltage varying from 1.3 V to 3.3 V. Therefore, the tuning range is about 90.38% which is larger than most of the LC and ring oscillator. The VCO circuit, which is constructed using a standard 0.35 μm CMOS technology, occupies only 26.25 × 7.52 μm2 die area and dissipated 10.56 mW under a 3.3 V supply voltage.

Highlights

Wireless communication systems contain low-noise amplifiers, mixers, power amplifiers, and phase-locked loops (PLLs)
We demonstrate the design of a novel voltage-controlled oscillator (VCO), which is based on a metal-oxide-semiconductor field-effect transistor (MOS) differential amplifier with active load
The phase noise is –120 dBc/Hz at 600 KHz offset from a 1.216 GHz carrier frequency

Summary

Introduction

Wireless communication systems contain low-noise amplifiers, mixers, power amplifiers, and phase-locked loops (PLLs). The low phase noise, wide tuning range, and low power dissipation and are the most important factors of the basic design of a VCO. The operations of the LC oscillators are excellent in phase-noise performance but their tuning ranges are only about 10% to 20% [1,2,3] They often require extra processes and occupy a large area of chip size due to the existence of inductor and capacitor. The ring oscillators have wide tuning range but they are poor in phase-noise performance. Wide tuning range is required in VCO for supporting broadband and multiband RF transceivers This VCO circuit, which is fabricated using a standard 0.35 μm CMOS technology provided by the Taiwan Semiconductor Manufacturing Company (TSMC) foundry, occupies 26.25 × 7.52 μm die area and dissipated 10.56 mW under 3.3 V supply

Circuit Design

Measured Results

Design

Conclusion