1N4491

Single Zener Diodes Overview

The Microchip Technology 1N4491 is a military-qualified, voidless hermetically sealed glass Zener diode rated at 1.5 watts steady-state power dissipation. It features a nominal Zener voltage of 120 V with a standard tolerance of ±5%. The device operates within a junction and storage temperature range of -65°C to +175°C. Electrical characteristics include a maximum dynamic impedance of 400 Ohms at the test current of 2.0 mA, a maximum reverse leakage current of 0.25 µA at 100 V, and a maximum continuous regulator current of 12 mA.

Single Zener Diodes Feature Summary

• Hermetically sealed construction using void-less hard glass with tungsten slugs for robust reliability.
• Qualified per MIL-PRF-19500/406 for high-reliability applications where failure is not tolerated.
• 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

• High-reliability voltage regulation circuits
• Military and aerospace electronic systems
• Radiation-hardened circuit protection

Single Zener Diodes Procurement Notes

Verify the specific qualification level required for your application, such as JAN, JANTX, JANTXV, or JANS, as these designations indicate different reliability standards under MIL-PRF-19500/406. Confirm whether RoHS compliance is necessary, noting that compliant versions are available only on commercial grade parts. Ensure the ordering suffix matches the desired tolerance and packaging configuration before finalizing procurement.

Single Zener Diodes Selection Notes

Select the 1N4491 when a stable 120 V reference is needed in harsh environments requiring hermetic sealing. The component supports flexible axial-lead mounting terminals suitable for through-hole integration. Consider tighter tolerance options if the standard 5% variation is insufficient for the specific circuit requirements.

Single Zener Diodes Part Context

This component belongs to the 1N4460–1N4496 series of industry-recognized Zener voltage regulators. The series provides extensive selections from 3.3 to 200 volts, utilizing triple-layer passivation and internal metallurgical bonds to ensure durability. It is designed to replace older discrete solutions with a single, robust package capable of handling significant thermal stress.

Single Zener Diodes Replacement Considerations

Direct replacements must match the 120 V Zener voltage, 1.5 W power rating, and DO-41 axial lead package. Verify that any substitute component meets the same MIL-PRF-19500/406 qualification levels if military-grade reliability is mandated by the system design.

Single Zener Diodes FAQ

What is the maximum operating temperature for the 1N4491?

The junction and storage temperature range for the 1N4491 extends up to +175°C.

Is the 1N4491 sensitive to electrostatic discharge?

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