TCXO
Understanding TCXOs
TCXOs provide an excellent balance of temperature stability, cost, power consumption, and size for applications requiring better than +/- 5 ppm stability. They fit between inexpensive XOs and costly OCXOs in the performance hierarchy.
TCXO Technology
- Analog TCXO: Thermistor network drives a varactor for frequency compensation. +/- 1-2 ppm. Simple, low cost.
- Digital TCXO (DTCXO): Temperature sensor + digital lookup table + DAC drives varactor. +/- 0.1-0.5 ppm. Most common today.
- MEMS TCXO: Silicon MEMS resonator with digital compensation. Small, low power. +/- 0.5-1 ppm.
TCXO Applications
- Cellular: TCXO provides the reference for the baseband processor. +/- 0.5 ppm typical for 4G/5G.
- GPS: TCXO aids satellite acquisition and tracking. +/- 1-2 ppm is adequate for GPS.
- Instruments: Portable spectrum analyzers, counters. +/- 0.5 ppm or better.
Frequently Asked Questions
What is a TCXO?
A TCXO uses electronic temperature compensation to stabilize crystal oscillator frequency to +/- 0.5 ppm or better (vs +/- 20 ppm for uncompensated XO). Standard in cellular phones, GPS receivers, and portable instruments.
TCXO vs OCXO?
TCXO: +/- 0.5 ppm, small, low power, seconds to stability. OCXO: +/- 0.01 ppm, large, high power (1-5W for oven), minutes to stabilize. Use TCXO for mobile/portable; OCXO for lab/base station.
What stability does 5G require?
5G NR requires +/- 0.1 ppm for base stations (stratum 3 level, typically OCXO or GPS-disciplined). +/- 0.5 ppm for handsets (TCXO). mmWave 5G benefits from better stability due to higher carrier frequencies.