1N4494

Single Zener Diodes Overview

The Microchip Technology 1N4494 is a military-qualified Zener voltage regulator diode designed for high-reliability applications. It features a hermetically sealed voidless glass package with internal metallurgical bonds. The device provides a nominal Zener voltage of 160 V with a standard tolerance of ±5%. It operates within a junction temperature range of -65°C to +175°C and dissipates up to 1.5 W at a lead temperature of +112°C. Key electrical parameters include a test current (IZT) of 1.6 mA, a maximum dynamic impedance (ZZT) of 1000 Ohms, and a maximum reverse leakage current of 25 µA.

Single Zener Diodes Feature Summary

• Hermetically sealed voidless glass construction with internal metallurgical bonding for robustness.
• Qualified per MIL-PRF-19500/406 standards for high-reliability environments.
• Inherently radiation hard as described in Microsemi MicroNote 050.
• Non-sensitive to electrostatic discharge (ESD) per MIL-STD-750 method 1020.

Single Zener Diodes Applications

• Voltage regulation over broad operating current and temperature ranges.
• High-reliability aerospace and defense circuits where failure is not tolerated.
• Radiation-hardened electronic systems.

Single Zener Diodes Procurement Notes

Verify the specific reliability level required, such as JAN, JANTX, JANTXV, or JANS, as these designations affect qualification standards. Confirm RoHS compliance status if applicable, noting that compliant versions are available only on commercial grades. Ensure the ordering suffix matches the desired tolerance and packaging configuration before finalizing procurement.

Single Zener Diodes Selection Notes

Select this component when a 160 V Zener voltage is required in a 1.5 W power rating package. Consider the DO-41 axial-lead form factor for through-hole mounting or the D-5A MELF variant for surface mount needs. Evaluate the thermal resistance and derating curves to ensure adequate heat dissipation within the specified -65°C to +175°C operating range.

Single Zener Diodes Part Context

The 1N4494 belongs to the 1N4460–1N4496 series of industry-recognized Zener voltage regulators. This series offers selections from 3.3 to 200 volts with standard 5% tolerance, alongside tighter 1% and 2% options. The devices utilize a voidless glass package with tungsten slugs and triple-layer passivation for enhanced durability and performance in demanding conditions.

Single Zener Diodes Replacement Considerations

Direct substitutes within the same series include other 1N44xx part numbers with similar voltage ratings. For equivalent specifications, verify compatibility with MIL-PRF-19500/406 qualified parts from Microchip or authorized manufacturers offering identical hermetic sealing and metallurgical bond constructions.

Single Zener Diodes FAQ

What is the maximum continuous Zener current for the 1N4494?

The maximum continuous regulator current (IZM) for the 1N4494 is 8.9 mA.

Is the 1N4494 sensitive to electrostatic discharge?

No, the device is non-sensitive to ESD per MIL-STD-750 method 1020.