The most stable clock money can buy.
An OCXO holds its quartz crystal at a constant 75 °C inside a tiny temperature-controlled oven. The result: stability of a few parts per billion — three orders of magnitude better than a TCXO, the reference clock for 5G fronthaul, Stratum networks and atomic-clock holdover.
1000× more stable than a standard TCXO.
The stability scale spans seven orders of magnitude — from parts-per-thousand of a crystal blank to parts-per-trillion of a caesium reference. OCXOs sit firmly in the parts-per-billion zone, where 5G and atomic-clock holdover designs need to be.
What an OCXO buys you. And what it costs.
Best-grade OCXOs achieve ±5 ppb over −40 to +85 °C. Stratum 3 / Stratum 3E network synchronisation class.
Femtosecond-grade phase noise for radar, 5G fronthaul, and instrumentation. Far cleaner than TCXOs.
The oven needs a few minutes to reach 75 °C. Plan for warm-up in equipment power-up sequences.
The oven draws ~1.5 W continuously. Plan thermals — not for battery designs, ideal for AC-powered infrastructure.
OCXOs aren't for everyone. Here's the honest trade-off.
An OCXO is the right answer when nothing less than ppb-class stability will do. For most embedded designs, a good TCXO is the better choice — smaller, cheaper, lower power, no warm-up. Use this table to decide.
When to choose an OCXO
- Stratum-class telecom synchronisation (5G fronthaul, IEEE 1588 PTP grandmasters)
- Atomic-clock holdover during GPS outage (free-run accuracy of days, not hours)
- Radar and electronic warfare — phase noise far below TCXO
- Metrology, calibration labs, frequency standards
- Optical transport networks (OTN), aviation, defence
When a TCXO is better
- Battery-powered designs — OCXO power consumption is 1000× higher
- Tight board space — OCXOs are 9 × 14 mm and up, vs 2 × 2.5 mm TCXOs
- Cost-sensitive volume designs — OCXOs are 10× to 50× more expensive
- Instant-on requirements — TCXO is stable in seconds, OCXO needs minutes
- Most consumer and IoT applications — overkill
Where OCXOs earn their watts. Infrastructure-class timing.
Stratum-3E reference clocks for 5G base stations and small-cell radio units. ±5 ppb meets ITU-T G.8273.2 holdover specs.
Maintains time within microseconds during GPS signal loss. Critical for power-grid synchrophasors and financial trading networks.
Coherent radar systems and electronic warfare receivers need ultra-low phase noise. OCXO delivers −150 dBc/Hz.
Frequency counters, signal generators, calibration references. Where measurement uncertainty must be in the parts-per-billion.
Need an OCXO? Let's discuss the spec.
OCXOs are project-specific. Send us your stability requirement, holdover target, supply voltage and form factor — we'll respond within one business day with the right options and a sample plan.
The most stable clock money can buy.
An OCXO holds its quartz crystal at a constant 75 °C inside a tiny temperature-controlled oven. The result: stability of a few parts per billion — three orders of magnitude better than a TCXO, the reference clock for 5G fronthaul, Stratum networks and atomic-clock holdover.
1000× more stable than a standard TCXO.
The stability scale spans seven orders of magnitude — from parts-per-thousand of a crystal blank to parts-per-trillion of a caesium reference. OCXOs sit firmly in the parts-per-billion zone, where 5G and atomic-clock holdover designs need to be.
What an OCXO buys you. And what it costs.
Best-grade OCXOs achieve ±5 ppb over −40 to +85 °C. Stratum 3 / Stratum 3E network synchronisation class.
Femtosecond-grade phase noise for radar, 5G fronthaul, and instrumentation. Far cleaner than TCXOs.
The oven needs a few minutes to reach 75 °C. Plan for warm-up in equipment power-up sequences.
The oven draws ~1.5 W continuously. Plan thermals — not for battery designs, ideal for AC-powered infrastructure.
OCXOs aren't for everyone. Here's the honest trade-off.
An OCXO is the right answer when nothing less than ppb-class stability will do. For most embedded designs, a good TCXO is the better choice — smaller, cheaper, lower power, no warm-up. Use this table to decide.
When to choose an OCXO
- Stratum-class telecom synchronisation (5G fronthaul, IEEE 1588 PTP grandmasters)
- Atomic-clock holdover during GPS outage (free-run accuracy of days, not hours)
- Radar and electronic warfare — phase noise far below TCXO
- Metrology, calibration labs, frequency standards
- Optical transport networks (OTN), aviation, defence
When a TCXO is better
- Battery-powered designs — OCXO power consumption is 1000× higher
- Tight board space — OCXOs are 9 × 14 mm and up, vs 2 × 2.5 mm TCXOs
- Cost-sensitive volume designs — OCXOs are 10× to 50× more expensive
- Instant-on requirements — TCXO is stable in seconds, OCXO needs minutes
- Most consumer and IoT applications — overkill
Where OCXOs earn their watts. Infrastructure-class timing.
Stratum-3E reference clocks for 5G base stations and small-cell radio units. ±5 ppb meets ITU-T G.8273.2 holdover specs.
Maintains time within microseconds during GPS signal loss. Critical for power-grid synchrophasors and financial trading networks.
Coherent radar systems and electronic warfare receivers need ultra-low phase noise. OCXO delivers −150 dBc/Hz.
Frequency counters, signal generators, calibration references. Where measurement uncertainty must be in the parts-per-billion.
Need an OCXO? Let's discuss the spec.
OCXOs are project-specific. Send us your stability requirement, holdover target, supply voltage and form factor — we'll respond within one business day with the right options and a sample plan.