Fuji Crystal
Quartz Crystal Frequency Ranges & Real‑World Applications
Release time:
2025-10-08 15:23
Quartz Crystal Frequency Ranges & Real‑World Applications
From quartz crystal frequency in the kHz band to crystal oscillator frequency ranges above 100 MHz, this field guide maps bands to protocols, SoCs, and packages—so you can pick the right crystal, XO/TCXO, or OCXO without guesswork.
Frequency‑to‑Application Heatmap (kHz → 100+ MHz)
kHz Band (32.768–200 kHz): Watches, RTCs, Deep Sleep Domains
The quartz crystal frequency that dominates here is 32,768 Hz (215). Binary divide‑by‑two counters yield a precise 1 Hz tick with sub‑µA power—ideal for watches, wearables, coin‑cell IoT, and MCU backup domains. Start‑up times of tuning‑fork resonators are seconds, so keep RTC logic in a backup island and avoid frequent power cycles. Packages are tiny—2.0×1.2 mm and 3.2×1.5 mm cans—and load caps are typically 6, 9, or 12.5 pF. For harsh ambient swings, a low‑power TCXO can bound drift without sacrificing standby current too much. For fundamentals behind the divide chain, see our 32,768 Hz explainer.
1–10 MHz: GNSS Front‑Ends & Lab/Network References
This band mixes two worlds: GNSS modules (e.g., 16.368 MHz is common in some GPS front‑ends) and standard references around 10 MHz used in lab equipment and network timing. In GNSS, the crystal feeds PLLs that lock to satellite carriers and IF chains; stability across temperature matters more than raw phase‑noise. For 10 MHz references, OCXOs provide ppm‑to‑ppb stability and low phase‑noise at the cost of warm‑up and power. Package sizes range from 7.0×5.0 mm XO/TCXO cans to larger OCXO modules (e.g., FOC‑6S).
10–40 MHz: Cellular, Wi‑Fi, and MCU SoCs
Here you’ll find the workhorses: 19.2/26/38.4 MHz for cellular modems and combo chips; 26/40 MHz for Wi‑Fi/BT SOCs; and 12–40 MHz for MCU master clocks. These frequencies are easy integer or rational multiples for RF subsystems, basebands, and USB interfaces. For consumer boards, 3.2×2.5 mm and 2.5×2.0 mm SMD oscillators balance cost and EMI. When outdoor temperature ranges widen, choose TCXO variants to hold tighter ±ppm over −40 to +85 °C. For parameter definitions, see XTAL parameters.
40–80 MHz: Wi‑Fi/BT High‑Speed Modes, Ethernet Intermediates
As PHY data rates and PLLs scale, many designs step into 40–80 MHz to simplify synthesis of 80/160 MHz Wi‑Fi clocks or to feed Ethernet PHYs that expect mid‑band refs. Choose low‑jitter XOs and watch supply decoupling; RF coexistence means spurs matter. Popular packages remain 3.2×2.5 and 2.5×2.0 mm, with HCMOS or clipped‑sine outputs depending on the receiver.
80–125+ MHz: Ethernet, SerDes, Video
Ethernet and SerDes stacks love clean multiples: 25/50/100 MHz dominate reference clocks with tight duty and low additive jitter. Pair high‑speed PHYs with low‑phase‑noise XOs or disciplined OCXOs where holdover matters. Consider spread‑spectrum low‑EMI families if emissions are tight—our FCO‑7C‑LE illustrates down‑spread and center‑spread options for digital video and surveillance products.
Common Frequencies Quicklook
Selection Tips: Stability, Noise, and System Constraints
- Stability (ppm/ppb) & temp drift: ±25/±50 ppm is common for consumer; GNSS/industrial tighter. Budget long‑term aging.
- Phase noise & jitter: High‑speed SerDes/Ethernet are jitter‑sensitive; check 12 kHz–20 MHz integrated jitter and close‑in phase noise.
- XO vs TCXO vs OCXO: Balance power/size/warm‑up against stability and holdover needs.
- Output & load: HCMOS vs clipped‑sine; verify receiver thresholds, load caps, routing, isolation.
- Power & decoupling: Place 0.1 µF + 1 µF near Vdd‑GND; manage grounds and keep away from high dv/dt nodes.
Quick Map: Band → Typical Protocols/Interfaces
| Band | Typical protocols / interfaces | Recommended devices |
|---|---|---|
| 32.768–200 kHz | RTC ticks, deep‑sleep counters | FCO‑3K · FVT‑2S |
| 1–10 MHz | GNSS IF/PLLs, 10 MHz lab/network references | FVT‑2S · FOC‑1D / FOC‑6S |
| 10–40 MHz | Cellular baseband, Wi‑Fi/BT refs, MCU master clocks, USB (12/24/48) | FCO‑7C |
| 40–80 MHz | High‑speed Wi‑Fi/BT modes, mid‑band Ethernet PHYs | FCO‑7C · FCO‑7C‑LE |
| 80–125+ MHz | Ethernet 25/50/100 MHz, SerDes, video scalers | FCO‑7C · FCO‑7C‑LE |
Suggested Packages & Oscillator Types
| Band | Package examples | Oscillator type | Recommended devices |
|---|---|---|---|
| 32.768–200 kHz | 2.0×1.2, 3.2×1.5 mm tuning‑fork | Crystal + RTC oscillator, ultra‑low power | FCO‑3K · FVT‑2S |
| 1–10 MHz | 7.0×5.0 mm; OCXO modules | XO/TCXO for GNSS; OCXO for 10 MHz refs | FVT‑2S · FOC‑1D / FOC‑6S |
| 10–40 MHz | 3.2×2.5, 2.5×2.0 mm | XO/TCXO (HCMOS or clipped‑sine) | FCO‑7C |
| 40–80 MHz | 3.2×2.5, 2.5×2.0 mm | Low‑jitter XO/TCXO | FCO‑7C · FCO‑7C‑LE |
| 80–125+ MHz | 7.0×5.0, 5.0×3.2 mm | Low‑jitter XO; OCXO for holdover | FCO‑7C · FCO‑7C‑LE |
Recommended Products
32.768–200 kHz · RTC / Wearables
FCO‑3K 32.768 kHz Watch Crystals · FVT‑2S Ultra‑Low‑Power TCXO
1–10 MHz · GNSS & 10 MHz References
FVT‑2S GNSS‑grade TCXO · FOC‑1D 10 MHz OCXO · FOC‑6S Low Phase‑Noise OCXO
10–40 MHz · Cellular / Wi‑Fi / MCU
40–80 MHz · Wi‑Fi High‑Speed / Ethernet
80–125+ MHz · Ethernet / SerDes / Video
References & Further Reading
application
Fcom
Automotive Electronics
Fire-fighting
Quartz Crystal
OCXO
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©Fuji Crystal (Hong Kong) Electronics Co., Ltd. All Rights Reserved.
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