by Bill Schweber @ digikey.com:
With very few exceptions, every electronic circuit needs an oscillator, also referred to as a clock, clock generator, or timing circuit. Its role is to provide the “heartbeat” for the processor, memory functions, communications ports, A/D and D/A converters (if any) and many other functions. In non-critical, low-budget situations such as $10 mass-market electronic thermometers, this clock may be made from a simple resistor/capacitor (RC) oscillator. However, for the vast majority of situations which are more critical, the oscillator is based on a quartz crystal (Figure 1). This is a mature (80+ years) and highly effective technology which can support of wide range of frequencies from kHz to hundreds of MHz, with performance spanning fairly good to excellent, depending on the crystal cut, fabrication, packaging, and other considerations.
MEMS Oscillators Challenge Quartz Crystals in RF Applications - [Link]
by Steve Taranovich:
I recently spoke to Piyush Sevalia, Executive Vice President, Marketing at SiTime Corporation,about their newly introduced 32 kHz TCXO (temperature compensated oscillator) which they claim to be the smallest, lowest power device in the industry. With its tiny footprint and ultra-low power consumption, the SiT1552 MEMS TCXO decreases the size and increases battery life of wearable electronics and Internet of Things (IoT); such benefits are not achievable from legacy quartz devices.
SiTime enters wearables, IoT markets with 32 kHz MEMS TCXO - [Link]
IQD frequency products have introduced a new range of temperature compensated voltage controlled crystal oscillators (TCVCXO) in a miniature 8-pad 5 x 3.2 mm outline. The IQXT-210 series TCVCXO, offers frequency stability down to ±0.14ppm over the full industrial temperature range of -40 to 85ºC.
Powered from a 3.3V supply the IQXT-210 has a typical current draw of only 12 mA (dependent upon oscillator frequency). The frequency can be specified between 10 MHz to 50 MHz. Initially there are 11 standard frequencies available including 12.8 MHz, 19.2 MHz and 26.0 MHz. Output can be specified as either HCMOS, 15pF load or Clipped Sine, into 10k Ohms load.
Tiny TCVCXO gets close to oven–controlled crystal stability - [Link]
Crystals and crystals oscillators from German company Jauch belong to the best what´s available on the market.
If we need an exact frequency, we usually reach for crystals or crystal oscillators. If we want a stable function in a wide temperature range and in various circuits, we reach for products of a renowned producer … Crystals belong to components which we usually choose by a frequency and package. That´s sufficient in the most of cases, but less known and less compared are many other qualitative parameters (which even don´t have to be in the datasheet), which depend mainly on the production technology and from a quality of a crystal itself. Quality (Q), low phase noise, stability of oscillations, low sensitivity to mechanical vibrations and other factors have influence on the final device and its functionality in less favorable conditions in praxis (temperature, load, drive level, aging, …).
Crystals and crystal oscillators from German company Jauch Jauch belong to a top and they´re price affordable at the same time, that´s in our portfolio in this segment can be found only these quality components with guaranteed specification. Production portfolio of company Jauch is very wide, from common crystals in a HC49/U package to miniature SMT versions. Popular and often more beneficial are the ready-made crystals oscillators, which have a built-in electronics of an oscillator and provide directly an output signal of a desired frequency (usually HCMOS). In the Jauch portfolio can also be found voltage controlled oscillators – VCO and also extremely stable temperature compensated crystal oscillators – TCXO. The best insight into basic series will give you the Jauch product overview.
Jauch – refined like a crystal - [Link]
This is another common device people use everyday, in which a circuit drives the motor found in our watches or clocks to determine the time.
The circuit is mainly operated by PCA1462U IC, specially suited for battery-operated quartz-crystal controlled wrist watches. The quartz crystal is used to input an oscillated signal to the PCA1462U IC then produces an output of pulses that drives the stepping motor ON.
The IC used in this circuit is specialized for this application featuring an amplitude regulated 32KHz oscillator, with excellent frequency stability resulting in a high immunity from oscillator-to-leakage currents. The loss of motor steps is not possible because of an on-chip detection on the induced motor voltage, this output is applicable for different types of bipolar stepping motors. This IC also has a very low current consumption; typically 170 nA, and the time calibration of the pulses is electrically programmable and reprogrammable (via EEPROM).
- PCA1462U CMOS integrated circuit
- 1.55V dc power source
- Quartz Crystal Oscillator
- Stepper Motor
Quartz-crystal Controlled Wrist Watch – [Link]
This project is “NanoUtils Xtal” – a crystal oscillator breakout board. The board is designed to be interfaced with microcontrollers that have their oscillator pins next to a ground pin. [via]
This board is a breakout containing a SMD crystal, two caps and a resistor meant to be used in breadboards when building something with an Atmel ATmega or a Microchip PIC that have the two crystal pins next to a GND pin. For instance the atmega328 or pic18f2550.
Crystal oscillator breakout - [Link]
This application note summarizes the crystal basics, PCB layout considerations, and how to test a crystal in your application. A crystal selection guide shows recommended crystals tested by experts and found suitable for various oscillator modules in different Atmel AVR families. Test firmware and test reports from various crystal vendors are included.
Selecting and testing 32kHz crystal oscillators - [Link]
Learning to design your own PCBs and being able to put together a schematic to solve a specific problem is both a valuable and rewarding skill. There are a number of resources out there to help you avoid common mistakes, but it isn’t always obvious to know where the values of certain common components come from, particularly common parts like resistors and capacitors. Figuring this out is part of the learning process, but it isn’t always easy to know where to look since you first need to know exactly the right terms to search for.
Choosing the Right Crystal and Caps for your Design - [Link]
There are many projects that require an accurate 1Hz clock signal, most involving the measurement of time, or controlling something based on time. There are timers, time clocks, nixie and other real time clocks, and many others. In my case, I wanted to build a very simple frequency counter. That circuit, in essence, simply counts how many pulses happen within 1 second. To make the counter as accurate as possible I needed my 1 second counting period to be as accurate as possible.
Crystal Controlled 1Hz Time Base - [Link]