HC-49S-8MHz-20pF
Standard HC-49/S through-hole crystal resonator, 8MHz frequency, 20pF load capacitance, ±30ppm tolerance, ideal for m...
Product Overview
Description
The HC-49S-8MHz-20pF is a high-quality quartz crystal resonator in the standard HC-49/S through-hole package. It provides a stable 8MHz frequency reference with ±30ppm tolerance, suitable for microcontroller clock and general timing applications.
This crystal features 20pF load capacitance, compatible with most 8-bit and 32-bit microcontrollers. The HC-49/S package offers excellent mechanical stability and is ideal for through-hole PCB designs, prototypes, and cost-sensitive applications.
With low ESR and reliable oscillation characteristics, this crystal ensures stable clock generation across the commercial temperature range of 0°C to +70°C. It is widely used in consumer electronics, industrial control, and communication devices.
Product Series
HC
Primary Application
Microcontroller clock source
Key Features
- Standard HC-49/S package for easy prototyping
- 8MHz frequency for common microcontroller clocks
- 20pF load capacitance for wide compatibility
- Low ESR for reliable oscillation
- ±30ppm tolerance for general applications
- Cost-effective solution for high-volume production
- Excellent mechanical stability
- RoHS compliant
Specifications
| Frequency | 8.000 MHz |
|---|---|
| Tolerance | ±30 ppm |
| Load Capacitance | 20 pF |
| ESR | ≤60 Ω |
| Drive Level | 10-100 μW |
| Temperature Range | 0°C to +70°C |
| Aging | ±3 ppm/year |
| Package | HC-49/S Through-Hole |
Applications
Microcontroller clock source
Industrial automation and control
Consumer electronics timing
Consumer electronics
Industrial control systems
Industrial automation and control
Communication interfaces
Communication and interface
LED driver controllers
Motor drive and control systems
Power supply controllers
Power conversion and supply
FAE Expert Insights
"The HC-49S-8MHz-20pF is my go-to recommendation for 8-bit microcontroller applications. The HC-49/S package is reliable and cost-effective. I have used this crystal in hundreds of customer designs with excellent results. The 20pF load capacitance works well with most MCUs including STM8, STM32, and PIC. For reliable oscillation, I recommend 22pF load capacitors with typical PCB stray capacitance. The ±30ppm tolerance is sufficient for UART communication up to 115200 baud. For applications requiring tighter tolerance, XGHC offers ±10ppm and ±20ppm options. This crystal is ideal for cost-sensitive consumer products where through-hole mounting is acceptable."
Reliable 8MHz crystal for microcontroller applications with excellent cost-performance ratio
— Michael Zhang, BeiLuo
Frequently Asked Questions
What load capacitors should I use with this crystal?
For HC-49S-8MHz-20pF with CL=20pF, use two 22pF ceramic capacitors (C1 and C2). The calculation is: C1 = C2 = 2 × (CL - Cstray), where Cstray is typically 3-5pF. So C1 = C2 = 2 × (20 - 4) = 32pF, use standard 33pF or 22pF. Actual value may need fine-tuning based on PCB layout and stray capacitance. Use C0G/NP0 ceramic capacitors for best temperature stability. Verify actual frequency with frequency counter and adjust capacitors if needed.
Start with 22pF capacitors and verify frequency. Adjust if measured frequency is off.
Can I use this crystal for UART communication?
Yes, HC-49S-8MHz-20pF with ±30ppm tolerance is suitable for UART communication. At 8MHz, ±30ppm equals ±240Hz frequency variation. For standard UART baud rates, this provides adequate accuracy. For 115200 baud, the error from crystal tolerance is well within acceptable limits (<2%). However, for maximum baud rate accuracy or multi-device communication, consider ±20ppm or ±10ppm tolerance versions. Also ensure your PCB layout follows best practices for reliable oscillation. Test communication across temperature range if operating in varying environments.
±30ppm is sufficient for most UART applications. Choose tighter tolerance for maximum accuracy.
What is the maximum drive level for this crystal?
The HC-49S-8MHz-20pF has a maximum drive level of 100μW. Exceeding this can cause: (1) Frequency shift due to thermal effects; (2) Accelerated aging; (3) Potential crystal damage in extreme cases. Typical microcontroller oscillator circuits drive crystals at 10-50μW, well within safe limits. To check drive level: measure crystal current with current probe, calculate power = I² × ESR. If drive level is too high, increase load capacitors or add series resistor. If too low (difficult start-up), decrease load capacitors. XGHC crystals are designed for reliable operation at standard MCU drive levels.
Standard MCU circuits typically provide safe drive levels. Contact FAE if you suspect drive level issues.
Can this crystal operate at industrial temperature range?
The standard HC-49S-8MHz-20pF is rated for 0°C to +70°C commercial temperature range. For industrial applications (-40°C to +85°C), XGHC offers industrial grade versions with extended temperature range and tighter temperature stability. The industrial version maintains reliable oscillation across the full industrial temperature range with slightly different specifications. For automotive applications (-40°C to +125°C), AEC-Q200 qualified versions are available. Specify temperature range when ordering to ensure correct part number.
Choose industrial grade for -40°C to +85°C operation. Contact FAE for industrial temperature options.
How do I verify the crystal is oscillating correctly?
To verify crystal oscillation: (1) Check MCU clock output pin with oscilloscope - should see clean 8MHz square wave; (2) Measure frequency with frequency counter - should be within tolerance (8MHz ±30ppm = 7.99976 to 8.00024 MHz); (3) Check MCU is executing code - blinking LED or UART output; (4) Verify oscillation amplitude - typically 0.5-1V peak-to-peak at crystal pins; (5) Check for stable waveform - no jitter or noise. If no oscillation: check load capacitors, verify PCB layout, check for solder shorts, ensure adequate drive level. XGHC crystals are 100% tested before shipment.
Use oscilloscope and frequency counter to verify oscillation. Contact FAE for troubleshooting assistance.