XO-25MHz-3.3V

This 25MHz oscillator is designed for 10/100Mbps Ethernet (Fast Ethernet). Gigabit Ethernet (1000Mbps) typically requires a 125MHz clock for the PHY. However, some Gigabit PHYs use 25MHz reference clock with internal PLL to generate 125MHz. Check your specific Ethernet PHY datasheet to confirm the required clock frequency. For standard 10/100Mbps Ethernet, this 25MHz oscillator is perfect. If you need 125MHz for Gigabit Ethernet, consider the XO-125MHz-3.3V. The stability and output specifications are suitable for both Fast and Gigabit Ethernet when the correct frequency is used.

Verify your Ethernet PHY clock requirements. Contact us for Ethernet oscillator recommendations.

The tristate (OE - Output Enable) pin allows you to enable or disable the oscillator output. When OE is high (or floating with internal pull-up), the output is active. When OE is low, the output goes to high-impedance state (tristate). This is useful for: 1) Power management - disable clock when not needed to save power. 2) Clock switching - select between multiple clock sources. 3) Testing - isolate the oscillator during board testing. 4) Hot-swapping - safely remove or insert clock without disturbing the system. Connect OE to your system control signal or leave floating for always-on operation. Check the datasheet for specific OE polarity and voltage levels.

Use tristate for power management or clock switching. Contact us for application guidance.

Proper power supply decoupling is essential for oscillator performance. Recommended decoupling: 1) 100nF ceramic capacitor (X7R or X5R) placed as close as possible to the VDD pin. 2) 1uF to 10uF bulk capacitor for low-frequency filtering. 3) Use short, wide traces between capacitor and oscillator. 4) Place ground vias near the capacitor ground. 5) Keep power traces away from high-speed signals. Poor decoupling can cause: Output jitter, frequency instability, increased phase noise, and startup problems. For best performance, follow the manufacturer's layout recommendations. The 100nF capacitor is the most critical for high-frequency noise filtering.

Use 100nF + 10uF decoupling capacitors close to VDD pin. Contact us for layout recommendations.

The CMOS output can typically drive 10 to 15 standard CMOS loads (depending on load capacitance). For multiple loads: 1) Calculate total load capacitance (sum of all load capacitances plus trace capacitance). 2) Keep total load under 15pF for best performance. 3) Use clock buffer if driving many loads or long traces. 4) Keep trace lengths short and matched if driving multiple devices. 5) Consider using termination resistors for long traces. If the load is too heavy, you may see: Slow rise/fall times, reduced amplitude, increased jitter, and waveform distortion. For driving multiple loads, a clock buffer or multiple oscillators may be better.

Calculate total load capacitance. Use clock buffer for heavy loads. Contact us for fan-out recommendations.

CMOS (Complementary Metal-Oxide-Semiconductor) and TTL (Transistor-Transistor Logic) have different output characteristics: CMOS - Rail-to-rail output swing (0V to VDD), high noise margin, low power consumption, modern standard. TTL - Output swing typically 0.4V to 2.4V (for 5V), lower noise margin, higher power consumption, legacy standard. This oscillator uses CMOS output which is compatible with most modern digital logic. CMOS provides better noise immunity and lower power. For interfacing with legacy TTL circuits, level shifting may be required. Most modern MCUs and FPGAs use CMOS logic levels and are directly compatible.

CMOS is compatible with modern digital systems. Contact us for TTL output options if needed.