'Single-pin' integrated crystal oscillators

Abstract

-Oscillator configurations for integrated circuit (IC) applications where the quartz resonator can be connected between one pin of the IC and ground are presented. Excellent performance and good designability are obtained by applying negative feedback around a high-gain amplifier circuit and by including a symmetrical limiter in the feedback loop. The feedback mechanism provides an inherent buffering against load variations. Implementation examples in bipolar technology are discussed. A simple model for the negative impedance at the crystal port reveals the methods for avoiding parasitic oscillations due to the shunt capacitance of the crystal. The performance of a semicustom integrated oscillator with a simple structure is simulated and measured. In this oscillator a novel start-up technique is employed that ensures a stable and reliable start-up behavior.

New Quartz Crystal Oscillators Using the Current‐Feedback Operational Amplifier

“…Consider the oscillator structures shown in Figure Using the crystal equivalent circuit shown in Figure 2, the admittance Y3 can be expressed as r + sL1 + 1/sC + 1/sCo Y3 r/sCo + Zl/Co + 1/s2C1Co (2) where r is the crystal internal resistance, L1 is the crystal internal inductance, C1 is the crystal internal capacitance, and Co is the electrostatic capacitance between the two parallel plates of the crystal.…”

“…Quartz crystal oscillators built around various discrete and integratedcircuit active elements are available in the literature [1,2]. Of particular interest here are crystal oscillators built around the second-generation independent of the closed-loop gain and very high slew rate.…”

High-Frequency Oscillator Design for Integrated Transceivers

“…The crystal oscillator in Figure 2.4(c) belongs to the same group as the DRO. Similar to the DRO, they have an excellent spectral purity and very good long-term frequency stability too [23,41].…”

“…Within the framework of this thesis, crystal oscillators are considered to be low-frequency oscillators and fall outside the scope. A multitude of instructive books and publications are available on crystal oscillator design [23,[39][40][41].…”