1N4747UR-1

Overview

The 1N4747UR-1 is a high-reliability Zener diode manufactured by Microchip Technology. It features a nominal Zener voltage of 20V with a tight tolerance of 2%. The device is rated for 1W power dissipation and utilizes a hermetically sealed glass MELF (DO-213AB) package. Designed for robust performance, it supports a maximum operating temperature of 175°C and exhibits a maximum dynamic impedance of 22 Ω.

Feature Summary

• Hermetically sealed glass construction ensures environmental protection and long-term stability in harsh conditions.
• High-reliability design suitable for aerospace, defense, and critical industrial applications requiring strict quality standards.
• Internal metallurgical bonding between the die and metal slugs provides superior mechanical strength and thermal conductivity.

Applications

• Voltage regulation in military-grade electronic systems
• Overvoltage protection circuits in aerospace avionics
• Precision reference voltage sources in high-temperature industrial sensors

Procurement Notes

Verify the specific suffix UR-1 to confirm the inclusion of MIL-PRF-19500 screening and hermetic sealing. Standard commercial versions may lack these high-reliability attributes. Confirm RoHS status as non-compliant due to lead-based terminations. Ensure procurement channels are authorized to guarantee authenticity and traceability for qualified components.

Selection Notes

Select this component when a 20V regulation point is required with high precision and extreme temperature resilience. The DO-213AB package offers a surface-mount footprint equivalent to through-hole variants while providing enhanced durability. Consider the 2% tolerance for applications demanding tighter voltage control than standard 5% devices.

Part Context

This part belongs to the 1N47xx series of Zener diodes, specifically the high-reliability UR-1 variant. Unlike standard commercial equivalents, the UR-1 designation indicates adherence to rigorous military specifications, including burn-in testing and defect prevention protocols. It serves as a surface-mount alternative to traditional axial-leaded regulators without compromising reliability.

Replacement Considerations

Direct substitutes include other 1N4747 variants with matching 20V/1W ratings, such as 1N4747A or 1N4747AG, provided hermetic sealing is not mandatory. For surface-mount replacements, verify that the alternative package matches DO-213AB dimensions and maintains comparable thermal and electrical characteristics.