TCXO Advantages and Disadvantages: A Comprehensive Overview

This page explores the advantages and disadvantages of TCXOs (Temperature Compensated Crystal Oscillators). It compares them to other types of crystal oscillators, highlighting their strengths and weaknesses.

What is a TCXO?

TCXO stands for Temperature Compensated Crystal Oscillator. These oscillators are commonly used in communication devices because they can adjust the frequency based on changes in the surrounding temperature.

Figure 1, shown below, illustrates the working principle of a typical TCXO.

Advantages of TCXO

Here are some key advantages of using a TCXO:

• Superior Temperature Performance: TCXOs offer significantly better temperature stability compared to other crystal oscillators, typically by a factor of 10 to 40.
• Variety of Package Sizes: They are available in a wide range of package sizes to suit different application needs.
• Flexible Output Options: TCXOs can provide both clipped sine wave and standard sine wave outputs.
• Low Power Consumption: They generally operate with a 3V supply and draw a small current, often around 2 mA.
• Diverse Compensation Methods: TCXOs come in various types, utilizing analog, digital, or combined analog-digital compensation networks. Common types include ADTCXO, DTCXO, DCXO, and MCXO.

Disadvantages of TCXO

While TCXOs offer many benefits, they also have some drawbacks:

• Cost: Achieving very high performance (e.g., +/- 1.5 ppm over a temperature range of 0°C to 70°C) increases the cost of the TCXO.
• Higher Power Dissipation: Compared to simpler oscillators, TCXOs consume more power due to the additional compensation circuitry.
• Stabilization Time: TCXOs require a certain amount of time to stabilize after being powered on, which can be 100 ms or longer.