1N2981B

Overview

The Microchip Technology 1N2981B is a hermetically sealed silicon Zener diode designed for high-power voltage regulation applications. It features a nominal Zener voltage of 17V with a tolerance of 5% and a maximum power dissipation rating of 10W. The device utilizes a DO-4 (DO-203AA) glass axial leaded package, ensuring robust performance in demanding environments. Key electrical characteristics include a maximum dynamic impedance of 4Ω at the test current and a unidirectional configuration. The component is constructed with a single diode element and connects via a cathode terminal, suitable for through-hole mounting in industrial and military-grade circuits requiring stable reference voltages under high thermal stress.

Feature Summary

• Hermetically sealed glass construction for environmental protection
• High power handling capability up to 10W
• Stable 17V Zener voltage with 5% tolerance
• Low dynamic impedance for precise regulation

Applications

• High-power voltage reference circuits
• Overvoltage protection in industrial systems
• Military and aerospace electronic assemblies
• Precision power supply regulation

Procurement Notes

Verify compliance with specific environmental standards such as MIL-STD-883 if required for your application, as this part may be RoHS non-compliant due to its hermetic seal and lead content. Confirm the exact suffix designation matches your bill of materials, as packaging variations exist. Ensure sourcing channels provide traceability documentation for critical infrastructure projects. Check for obsolescence notices from Microchip before finalizing design-in decisions.

Selection Notes

Select the 1N2981B when a 10W power rating is necessary for voltage clamping or regulation tasks where standard small-signal diodes would fail thermally. Its DO-4 package offers superior heat dissipation compared to smaller axial packages. Consider the 17V nominal value against your circuit's operating range to ensure adequate headroom. The hermetic seal makes it preferable over plastic-packaged equivalents in harsh environments involving moisture or chemical exposure.

Part Context

This component belongs to the 1N298x series of high-power Zener diodes manufactured by Microchip Technology. These devices are legacy parts often specified in older military and industrial schematics. They serve as direct replacements for similar JEDEC-style numbered Zener diodes from other manufacturers. The series is characterized by its rugged glass encapsulation and ability to sustain significant continuous power dissipation without degradation.

Replacement Considerations

Equivalent parts include the 1N2981A (with tighter tolerance) or generic 1N2981 variants from other qualified vendors. Verify pinout compatibility and thermal resistance values when substituting. Ensure the replacement maintains the same hermetic sealing requirements if used in radiation or vacuum environments.