What Is Temperature Compensated Crystal Oscillator (TCXO)?
TCXO is an oscillator with a temperature sensor and a temperature compensation circuit to minimize the frequency change due to changes in ambient temperature.
Uses of TCXOs
TCXOs are used in applications requiring frequency accuracy that cannot be achieved with a crystal oscillator or stable frequency accuracy over a wide temperature range.
Principle of TCXOs
A temperature sensor and circuits necessary for temperature compensation are added to the oscillation circuit to compensate for small changes in frequency caused by changes in ambient temperature. A crystal-based TCXO compensates the frequency by applying the voltage required for temperature compensation to a variable voltage capacitor such as a varicap, while MEMS-based TCXOs output temperature-compensated frequency with a decimal point PLL based on the information from a temperature sensor.
In addition to frequency stability, TCXO has other important specifications such as df/dT, vibration/shock resistance, and aging, which should also be considered when selecting components.