Application Notes - Statek

Tech Note 24: Comparison of Low Frequency Oscillator Designs

Crystal-controlled oscillators can be divided into two basic groups: positive reactance or negative reactance. The positive reactance mode is commonly called a “parallel resonant” or “antiresonant” oscillator. A pierce oscillator is one commonly-known positive reactance oscillator. The negative reactance mode is usually referred to as a series oscillator. Statek crystals are designed and tuned for a specific mode of operation ......


Tech Note 27: Soldering Guidelines for Crystals & Oscillators

Statek’s crystals and oscillators are hermetically sealed low thermal-mass devices requiring special attention before subjecting them to a soldering process. To avoid compromising the integrity of the seal or damaging the device, the temperature must not exceed a maximum allowable peak temperature, and even then the time at this peak temperature must not exceed a maximum allowable time. In Sections 2 and 3, we present the guidelines for Statek’s surface-mount and through-hole devices. In Section 4, we summarise the guidelines by device family. In Section 5, we provide a few tips for hand soldering. Lastly, in Section 6, we note some of the consequences of failing to follow the guidelines given here ......


Tech Note 28: An Ultra-miniature Low-profile AT Quartz Resonator

AT-cut quartz crystal resonators have been used in precision frequency control for more than 60 years and are today one of the most widely used types of crystals. While the conventional AT crystal is disc-shaped, the need for smaller components led to the development of the miniature AT-strip. To meet the needs of manufacturers for even smaller components, Statek Corporation has developed an ultra-miniature low-profile quartz crystal as part of its CX-4 family of products. For comparison, the CX-4 requires only about one-third the land area of the CX-1 and about one-half the land area of the CX-3 ......


Tech Note 29: Using CX-1V Crystals (200-240kHz) with Microchip Technology's PIC16C73A Microcontroller

We recommend component values when using Statek’s CX-1V crystals in the 200-240 kHz range with Microchip Technology’s PIC16C73A microcontroller (in the XT mode). The large capacitors (47-68 pF) recommended in Table 14-2 of Microchip Technology’s data sheet DS30390E cause the PIC16C73A to overdrive Statek’s crystals ......


Tech Note 30: Design Guidelines for Quartz Crystal Oscillators

A CMOS Pierce oscillator circuit is well known and is widely used for its excellent frequency stability and the wide range of frequencies over which they can be used. They are ideal for small, low current and low voltage battery operated portable products especially for low frequency applications. When designing with miniaturised quartz crystals, careful consideration must be given to the frequency, gain and crystal drive level. In this paper, the design equations used in a typical crystal controlled pierce oscillator circuit design are derived from a closed loop and phase analysis. The frequency, gain and crystal drive current equations are derived from this method ......


Tech Note 31: Practical Analysis of the Pierce Oscillator

To achieve optimum performance from a Pierce crystal oscillator, e.g. good frequency stability and low long term ageing, the crystal parameters, crystal drive current, and oscillator gain requirements must be carefully considered. Over many years of experience, it has been found that excessive crystal drive current is one of the main causes of oscillator malfunction. Overdriving the crystal causes frequency instability over time, and for tuning-fork crystals the excessive motional displacement can break the crystal tines. This technical note describes a practical approach to measuring the key parameters of a Pierce oscillator ......


Tech Note 32: The Quartz Crystal Model and its Frequency

In this note, we present some of the basic electrical properties of quartz crystals. In particular, we present the 4 parameter crystal model, examine its resonant and antiresonant frequencies, and determine the frequency at load capacitance. The model and analysis is applicable to most types of quartz crystals, in particular tuning-fork, extensional-mode, and AT-cut resonators ......


Tech Note 33: What is Frequency at Load Capacitance

When ordering crystals for oscillators that are to operate at a frequency f, e.g. 32.768 kHz or 20 MHz, it is usually not sufficient to specify the frequency of operation alone. While the crystals will oscillate at a frequency near their series resonant frequency, the actual frequency of oscillation is usually slightly different from this frequency (being slightly higher in “parallel resonant circuits”) ......


Tech Note 35: An overview of Oscillator Jitter

A basic measure of an oscillator's performance is its frequency stability (or instability depending on one's point of view). In the long term (timescales of days or years), we refer to frequency changes as ageing. On moderate timescales (seconds), the stability of an oscillator is oftern characterised in terms of its Allan Variance ...... 


Tech Note 36: Measurement of Oscillator Jitter

The purpose of this note is to summarise the methods that Statek use to measure oscillator jitter. in brief, we use the jitter measurement capabilities of the LeCroy WavePro 7100A oscilloscope with the JTA2 jitter analysis software package. With this and some signal amplification, jitter as low as about 1.5ps can be measured ......


Tech Note 37: Handling Guidelines for Crystal & Oscillator Products

This document provides guidelines for the handling of crystal or crystal oscillator products at the customer’s location. It covers product handling from the time that it is received at the customer’s dock and stored on the customer’s shelf through removal from the shipping box, board soldering and depaneling / singulation, and installation on the customer’s board in his final product ......