A Temperature-Compensated Digitally-Controlled Crystal Pierce Oscillator for Wireless Applications

📋 论文概要

本文提出一种基于Pierce振荡器的温度补偿数字控制晶体振荡器（DCXO），采用开关电容阵列代替传统的变容二极管和DAC，实现直接数字频率控制，适用于无线通信应用。

💡 主要创新点

• 使用开关电容阵列替代变容二极管，实现数字字直接控制频率，简化了模拟DAC转换环节。
• 集成温度补偿机制，提高晶体振荡器在全温范围内的频率稳定性。

🏷 关键词

📄 原文摘要

Sirenza Microdevices, San Jose, California The traditional analog approach for frequency control of a crystal oscillator (XO) uses a varactor embedded into the structure of the XO to tune its frequency. This method requires a DAC to convert the automatic frequency control (AFC) signal, which is often digital, to an analog voltage for tuning the varactor. A more direct approach would be to use a switched-capacitor (SC) array to control the frequency of a XO with a digital word; hence the name digitally controlled XO (DCXO) [1]. In our implementation, the DCXO is based on a Pierce oscillator with two MIM capacitor arrays for tuning the anti-resonant frequency of a 19.2MHz crystal (Fig. 19.7.1). Each array of MIM capacitors is thermometer-coded and formatted in a matrix shape to facilitate layout. Although a segmented architecture is an areaefficient method for implementing a SC array [2], a thermometercoded array provides the best linearity and guarantees a monotonic frequency tuning cha

👥 作者与机构

Shayan Farahvash, Chee Quek, Monica Mak