Column: Design with frequency components
High-stability clocking for modern connected devices
In this series we will focus on the diff erent component types for timing, synchronization and frequency control, their basic parameters and how to best use them in various applications
By Daphne Popescu, Product and Sales Management, and Wendy Stewart, Sales and UK Offi ce Manager, GEYER Electronic
I
n the fi rst part of this series, we provided an overview of the diff erent types of oscillators used in electronic designs, touching briefl y also on the temperature-compensated crystal oscillator, or TCXO. In this part
we want to explain why the TCXO is so important, by digging deeper into its role, evolution and commercial appeal. A TCXO is used in applications where
frequency stability and precision are mandatory, even when the temperature changes. A correction voltage is generated by a temperature sensing and compensation circuit that is constantly used for frequency correction. A typical TCXO temperature curve looks
relatively fl at, with only small variations, compared to an uncompensated crystal which follows a parabolic shape, both shown in Figure 1. T e temperature sensor measures the
environmental temperature which is activating the compensation circuit, and adjusts the oscillator's frequency back to the nominal frequency. Independent of the type of compensation
mechanism – analogue, digital or hybrid – this is a crucial aspect of a TCXO. Its role grows bigger as developers consider using a precise oscillator in many more applications than a crystal, even with the cost increase. However, it is obvious why: Besides providing a reliable reference clock
10 February 2026
www.electronicsworld.co.uk
for digital circuits and RF systems, TCXOs off er much better stability than standard frequency components. A standard crystal is designed for
frequency stability over temperature of 12-50ppm (typ), while a normal XO has a frequency stability of about 20-50ppm over the same industrial temperature range. A TCXO can typically reduce the frequency driſt to about 0.5-5ppm, depending on the application’s needs. Only an oven- controlled oscillator (OCXO) can undercut that to 0.01ppm, however at the cost of much higher power consumption.
TCXO selection – which one fi ts best? TCXOs are oſt en used in GPS receivers (since they require very precise timing), wireless communication systems (such as LTE, Wi-Fi, Bluetooth, etc.), high- precision instruments (like test and measurement), medical equipment that requires precision, IoT devices where temperature varies widely, and any type of digital system where clock precision matters. In the literature, when discussing TCXOs, the focus is frequently on its
Figure 1: TCXO compensation curve over temperature
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