1N4993

Single Zener Diodes Overview

The Microchip Technology 1N4993 is a military-qualified, voidless hermetically sealed glass Zener diode rated at 5 Watts. It features an axial lead 'E' package with copper leads and tin/lead finish. The nominal Zener voltage is 300 V at a test current of 4 mA. Key electrical parameters include a maximum reverse leakage current of 2 µA at 28 V, a maximum Zener impedance of 950 Ohms at the test current, and a maximum temperature coefficient of 0.120 %/°C. The device supports a continuous operating junction temperature range from -65°C to +175°C.

Single Zener Diodes Feature Summary

• Military qualified to MIL-PRF-19500/356 for high-reliability applications
• Voidless hermetically sealed glass construction with internal metallurgical bonds
• Inherently radiation hard as described in Microsemi MicroNote 050
• Nonsensitive to electrostatic discharge per MIL-STD-750 Method 1020

Single Zener Diodes Applications

• High-reliability aerospace systems where failure cannot be tolerated
• Military electronic circuits requiring robust voltage regulation
• Radiation-hardened power supply designs

Single Zener Diodes Procurement Notes

Verify that the specific order matches the standard 1N4993 designation without additional suffixes (such as C or D) if standard 5% tolerance is required. Confirm the package type corresponds to the axial lead configuration rather than surface mount variants. Ensure compliance with the specified military qualification standards is documented for the intended application environment.

Single Zener Diodes Selection Notes

Select this component when a 300 V regulation point is needed within a 5 Watt power dissipation envelope. Consider the high dynamic impedance of 950 Ohms; it may not suit low-noise precision references. Verify thermal management capabilities for operation up to 175°C junction temperature. Compare against lower voltage alternatives in the 1N4954 series if system requirements differ.

Single Zener Diodes Part Context

This part belongs to the 1N4954 through 1N4996 series of 5 Watt Zener Voltage Regulators manufactured by Microsemi (now Microchip Technology). These components are designed for demanding environments and utilize a specific voidless-glass construction method. The series covers a broad voltage range from 3.3 V to 390 V, with the 1N4993 representing the higher voltage end of the spectrum.

Single Zener Diodes Replacement Considerations

Direct replacements must match the 300 V nominal voltage, 5 W power rating, and axial lead package. Equivalent parts should also meet MIL-PRF-19500/356 qualifications if military reliability is required. Surface mount equivalents exist in the US suffix series but require different footprint considerations.