090-44330-21

Overview

The Microsemi Corporation part number 090-44330-21 identifies the SA.33m Rubidium Clock module with Automatic Tuning (AT) disabled. This component is an atomic clock oscillator designed for high-stability frequency generation. It operates at a nominal frequency of 10 MHz and utilizes CMOS output logic levels. The module requires a supply voltage of 5V to function correctly. Physically, it is housed in a square package measuring 2.000 inches by 2.000 inches, which corresponds to 50.80mm by 50.80mm. This configuration ensures compatibility with standard mounting footprints while providing the necessary isolation for atomic resonance.

Feature Summary

• Integrates a rubidium atomic frequency standard for superior long-term stability and accuracy compared to conventional crystal oscillators.
• Features a CMOS output interface compatible with standard digital logic circuits without requiring additional level shifting.
• Includes an automatic tuning mechanism that is specifically disabled in this variant, allowing for manual or external control of the resonator frequency.

Applications

• Telecommunications base stations requiring precise timing synchronization.
• Navigation and GPS reference systems needing stable frequency sources.
• Test and measurement equipment demanding low phase noise and high frequency accuracy.
• Military and aerospace platforms where radiation hardness and reliability are critical.

Procurement Notes

Verify the specific suffix '21' against the manufacturer's current documentation to ensure the AT-disabled configuration is intended. Confirm that the 5V supply requirement aligns with your system power architecture. Check for any updated pinout revisions or mechanical drawing changes since the original datasheet publication. Ensure handling procedures account for the sensitivity of the internal rubidium cell to shock and vibration during installation.

Selection Notes

Choose this module when application requirements exceed the stability limits of TCXO or OCXO technologies. The disabled AT feature makes it suitable for systems where external frequency control loops are preferred over internal automatic adjustment. Consider the physical size constraints due to the 50.80mm x 50.80mm footprint. Evaluate thermal management needs as atomic clocks generate heat from the heater elements maintaining the rubidium vapor cell temperature.

Part Context

This component belongs to the SA.3xM series of rubidium atomic clocks manufactured by Microsemi Corporation. The series includes variants such as the SA.31m and SA.35m, which may differ in frequency, output type, or automatic tuning configurations. The SA.33m specifically denotes the 10 MHz CMOS output version. These modules represent a class of high-reliability timekeeping devices used in infrastructure where frequency drift must be minimized over extended periods.

Replacement Considerations

Direct replacements within the same family include the SA.31m and SA.35m, provided their specific electrical characteristics match the design requirements. Verify that substitute models have the same 5V supply voltage and CMOS output logic. Ensure that the replacement also has the automatic tuning feature disabled if that is a critical design constraint. Cross-reference mechanical dimensions to guarantee fit within the existing enclosure.