Overview
The CAPAR 18.4320MHz HC-49/U quartz crystal resonator is a precision timing component designed for UART, microprocessor, and clock oscillator applications in industrial and commercial equipment. The 18.4320MHz frequency is commonly used in serial communication and timing circuits where stable, predictable oscillation is critical. This through-hole leaded crystal is packaged in the proven HC-49/U form factor, a industry-standard enclosure that remains the preferred choice for retrofit, repair, and new-build projects requiring proven reliability.
Key Features
- Frequency: 18.4320MHz — standard UART clock frequency
- Package: HC-49/U — robust, sealed through-hole package
- Low equivalent series resistance (ESR) — stable oscillation with minimal energy loss
- Wide frequency stability range — suitable for embedded systems and legacy equipment
- RoHS-compliant construction typical for modern manufacturing
Technical Specifications
The HC-49/U format is a time-tested enclosure designed for insertion into crystal socket holders or PCB footprints. Key electrical and physical characteristics include:
- Typical frequency tolerance: ±30–50ppm depending on load and temperature
- Operating mode: Fundamental
- Equivalent series resistance (ESR): Typically 40–60 Ohms
- Operating temperature range: −20°C to +70°C (standard industrial grade)
- Physical dimensions: Approximately 11.1mm L × 4.8mm W × 4.3mm H
- Mounting type: Through-hole leaded
Typical Applications
- UART and serial communication: 18.432MHz is a de facto standard for RS-232 and RS-485 baud-rate generation, supporting common rates (9600, 19200, 38400, 57600, 115200 baud).
- Microcontroller clock: Provides stable timing for 8051, PIC, AVR, and ARM-based embedded systems.
- Industrial equipment repair: Drop-in replacement for legacy oscillators in process control, data acquisition, and instrumentation.
- Test and measurement: Precision timing for signal generators, frequency counters, and diagnostic equipment.
- Telecommunications: Backup or redundant clock source in legacy switching and modem equipment.
Compatibility & Replacements
Compatible With
- Through-hole crystal socket holders (standard HC-49/U footprint)
- PCB designs expecting 18.432MHz timing input
- Microcontroller and UART clock generator circuits
- Legacy industrial and telecommunications equipment
- Standard frequency-setting circuits requiring fundamental-mode crystals
Replaces / Drop-In Replacement For
- Standard HC-49/U crystals at 18.4320MHz from any reputable manufacturer
- Legacy oscillator modules requiring 18.432MHz source
- Verify exact footprint and load capacitance specifications with your design documentation before substitution
Works With
- UART/USART serial communication protocols (RS-232, RS-485, TTL)
- Microcontroller oscillator circuits (8051, PIC, AVR, ARM, STM32)
- Fundamental oscillator mode circuits
- Industrial timing and clock distribution systems
