FCO-3K 32.768 kHz Low-Power RTC XO
SMD 3.2×2.5mm, 32.768kHz RTC XO
FEATURE
Product Description
FCO-3K — 32.768 kHz SMD Crystal Oscillator
A low-power 32.768 kHz CMOS XO for always-on RTC domains—optimized for compact footprints, simple clock gating (tri-state enable), and multi-voltage designs (1.8/2.5/3.3 V). Learn the fundamentals in What is a clock oscillator? and see the XO family overview: Crystal-Controlled Oscillators (XO).
1.8/2.5/3.3 V
35 μA @ no load
±10 ppm @ 25°C
CMOS, 15 pF load
≤ 20 ms
≤ 3 μA
Overview
The FCO-3K is a 32.768 kHz CMOS crystal oscillator in a compact 3.2×2.5×0.95 mm SMD package. It supports 1.8 V, 2.5 V, and 3.3 V supply options with a typical current of 35 μA at no load, ideal for RTC domains in wearables, smartphones, medical devices, and IoT nodes. A tri-state input (Pin 1) allows easy clock gating for ultra-low-power designs. For selection context, read What Are Timing Devices? and How does a quartz oscillator work?.
Design tip: Place a 0.1 μF bypass capacitor close to Vdd–GND pads to ensure optimal oscillator performance. If your system has strict wake-up timing, review start-up time causes & fixes.
Key Features
- 32.768 kHz nominal frequency with ±10 ppm tolerance at 25 °C.
- Ultra-low power: 35 μA (typ) @ no load; standby current ≤ 3 μA.
- 1.8 V / 2.5 V / 3.3 V supply options.
- CMOS output, 15 pF load, duty cycle 45–55%.
- Fast start-up: ≤ 20 ms.
- Tri-state enable/disable via Pin 1 (VIH ≥ 70% Vdd, VIL ≤ 30% Vdd).
- Package: 3.2×2.5×0.95 mm (typ); RoHS & REACH compliant.
Key Specs
Quick summary for system architects. Test condition note: typical values at 25 °C unless specified.
32.768 kHz
3.2×2.5×0.95 mm
CMOS, 15 pF load
Tri-state (Pin 1)
±3 ppm/yr (max)
45–55%
Need help mapping ppm to real-world RTC drift? Use our reference: PPM to seconds/day converter.
Applications
RTC / Timekeeping
Real-time clocks in wearables, smartphones, and embedded systems that require always-on low-power timing. Selection guide: selecting timing crystals for RTC.
Wearables & Medical
Fitness bands, smartwatches, portable medical monitors—battery-powered designs that need predictable low-frequency references. Application hub: oscillator clock applications.
IoT & Smart Home
Edge sensors, BLE beacons, security devices, and smart meters with tight energy budgets. For broader usage patterns, see oscillator electronics applications.
Industrial / Data Logging
Data loggers, gateways, and embedded control systems that need stable time bases for sleep/wake scheduling and timestamping. Related: networking & storage timing and test & measurement timing.
Detailed Specifications
Test conditions: Ambient temperature 25 ± 5 °C; relative humidity 40–70%; unless otherwise noted. Definitions: XTAL crystal oscillator parameters. For circuit theory background, see how crystal oscillators work.
| Parameter | Symbol | Min | Typ | Max | Units | Notes |
|---|---|---|---|---|---|---|
| Nominal Frequency | F | 32.768 kHz | kHz | |||
| Frequency Tolerance @ 25 °C | FT | ±10 | ppm | @ 25 °C ±3 °C | ||
| Supply Voltage | Vdd | 1.8 / 2.5 / 3.3 | V | No load | ||
| Current Consumption | Icc | 35 | μA | No load | ||
| Standby Current | Icc(ST) | 3 | μA | Tri-state disable | ||
| Output Load (CMOS) | CL | 15 | pF | |||
| Output High | VoH | 0.9 Vdd | V | |||
| Output Low | VoL | 0.1 Vdd | V | |||
| Rise / Fall Time (10–90%) | Tr / Tf | 15 | ns | |||
| Tri-State Enable (VIH) | VIH | 0.7 Vdd | V | Enable | ||
| Tri-State Disable (VIL) | VIL | 0.3 Vdd | V | Disable | ||
| Duty Cycle | TH/T | 45 | 55 | % | ||
| Start-up Time | Tosc | 20 | ms | |||
| Aging, first year @ 25 °C | — | ±3 | ppm/yr | Long-term guidance: oscillator aging | ||
Frequency stability includes calibration @ 25 °C, operating temperature, input voltage variation, load variation, first-year aging, shock, and vibration. For circuit-level considerations (load capacitance/drive level), see load capacitance & drive level.
Stability Options by Temperature Range
| Operating Range | ±25 ppm | ±30 ppm | ±50 ppm |
|---|---|---|---|
| −40 to +85 °C | Conditional | Available | Available |
| −40 to +105 °C | Conditional | Available | Available |
| −40 to +125 °C | Not available | Conditional | Available |
Curious how temperature and cut influence quartz behavior? Read Frequency Crystal Science.
Design Notes & Layout Tips
- Place a 0.1 μF ceramic bypass capacitor close to Vdd–GND pads.
- Keep the 32 kHz trace short and away from high-slew-rate nets to minimize injected jitter (typical Pierce oscillator routing rules apply).
- Startup margins follow the Barkhausen criterion; use the tri-state input (Pin 1) to gate the clock during deep sleep.
- If your design is sensitive to frequency pulling, review load capacitance & frequency pulling.
Ordering Code & Options
FCO-3K is available across multiple supply voltages and stability options. For extended temperature support, stability selection, screening, tape-and-reel, and labeling, please contact sales. If you need bare resonators for your own XO circuits, see our Timing Crystals.
Selection Path / Upgrade Options
If you are balancing footprint vs. current vs. temperature range, consider these internal references: XO family (industrial/automotive), common frequency ranges & recommended devices, and the frequency of oscillation guide.
Downloads
Need additional B2B documents (packing, labeling, reliability summary)? Email Fcom@fujicrystal.com.
FAQ
What is the typical current consumption?
Typical current is 35 μA at no load (supply-option dependent).
How do I disable the clock output?
Use the tri-state control on Pin 1. Drive it to ≥ 70% Vdd to enable and ≤ 30% Vdd to disable.
What output load does the device support?
CMOS output is specified for a 15 pF load.
How is frequency stability defined for this XO?
It includes calibration at 25 °C, temperature, supply/load variation, and aging. See XTAL parameters for definitions.
How is this different from a 32.768 kHz timing crystal?
A timing crystal is a passive resonator and needs an external oscillator circuit. FCO-3K is an integrated XO providing a ready-to-use CMOS clock. If you need passive parts, browse Timing Crystals.
Is the part RoHS/REACH compliant?
Yes, the device is RoHS and REACH compliant and Pb-free.
What is the MOQ and lead time?
MOQ and lead time depend on configuration (voltage, stability, screening) and inventory. Contact us with your target spec for a quick confirmation.
Can I get samples before mass production?
Yes. We support sampling for evaluation and can align the sample configuration with your mass-production option.
Do you support customization and screening?
Yes. We can support stability/temperature options, screening, tape-and-reel, labeling, and other B2B requirements—send your selection criteria for an RFQ.
How do I request pricing for this part?
This is a price-on-request B2B component. Email us your quantity, ship-to country, and configuration to receive a formal quotation.
Support & Compliance
Technical support and application engineering: Contact us or email Fcom@fujicrystal.com.
ISO certifications: ISO9001 · ISO14001
All specifications are subject to change without notice. Performance may vary with supply voltage, load, and temperature. For guaranteed limits and screening, please request the latest datasheet and a formal quotation.
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