Dapu Microelectronics Temperature Compensated Oscillators (TCXO)

Dapu TCXOs are available in multiple stability grades to meet different application requirements. Standard grades include ±2.5ppm for consumer and industrial applications, ±1.0ppm for wireless communication, ±0.5ppm for GPS and precision timing. The stability specification is the maximum frequency deviation over the specified temperature range. Higher stability (lower ppm) comes at higher cost and power consumption. GPS applications typically require ±0.5ppm or better for fast lock and accurate positioning. Cellular applications usually need ±1.0-2.5ppm depending on the standard. Select the grade that meets your system requirements with appropriate margin.

Select ±0.5ppm for GPS, ±1.0ppm for cellular, ±2.5ppm for general wireless. Contact us for specific recommendations.

TCXOs use temperature compensation circuits to counteract the natural frequency drift of quartz crystals with temperature. The crystal has a parabolic or S-shaped frequency vs. temperature curve with turning points around 25-30°C. A temperature sensor (thermistor or integrated sensor) measures the ambient temperature. Compensation circuitry generates a correction voltage based on the temperature reading. This voltage is applied to a varactor diode in the oscillator circuit, pulling the frequency in the opposite direction of the crystal's drift. The result is much flatter frequency vs. temperature characteristics, achieving 10-50x improvement over standard crystals. Dapu TCXOs use advanced compensation algorithms for optimal stability.

TCXO compensation is automatic. Select stability grade based on your application requirements.

Hysteresis in TCXOs refers to the frequency difference observed when approaching a temperature from opposite directions (heating vs cooling). Dapu TCXOs typically exhibit very low hysteresis of <0.1ppm, which is negligible for most applications. Low hysteresis is achieved through high-quality crystal material and optimized compensation algorithms. For precision applications where hysteresis could be a concern, we can provide characterization data. The low hysteresis ensures consistent frequency regardless of temperature history, which is important for applications with cyclic temperature variations.

Low hysteresis <0.1ppm suitable for all applications. Contact us for characterization data if needed.

Dapu TCXOs can be used in vacuum and space applications with proper consideration. In vacuum, heat transfer is different (no convection), which affects thermal characteristics. The TCXO may run slightly warmer in vacuum, but the temperature compensation still functions correctly. For space applications, radiation tolerance must be considered. Standard commercial TCXOs are not radiation-hardened. For space applications, we recommend using hermetically sealed packages and considering radiation effects. Contact our technical team for guidance on vacuum and space applications. Custom screening and testing can be arranged for high-reliability applications.

Suitable for vacuum with thermal considerations. Contact us for space application guidance.

Retrace (or warm-up repeatability) is the frequency deviation observed when power is cycled. Dapu TCXOs typically have excellent retrace of <0.1ppm after the initial warm-up period. This means if you power off and then power on again after the oscillator has stabilized, it will return to nearly the same frequency. Good retrace is important for applications with frequent power cycling. The retrace specification assumes the TCXO has completed its initial warm-up before power-off. For applications requiring the absolute best retrace, allow the TCXO to stabilize for several minutes before relying on the frequency accuracy.

Excellent retrace <0.1ppm. Allow full warm-up for best repeatability.