1N2818BU3

Overview

The Microchip Technology 1N2818BU3 is a high-power 50W Zener diode belonging to the JEDEC registered 1N2804B through 1N2846B series. It provides voltage regulation with a nominal Zener voltage of 20V and a tolerance of ±5%. The device features internal solder bond construction and is hermetically sealed in an industry-standard TO-204AD (TO-3) package. It supports operation up to 50W with adequate heat sinking, offering low thermal resistance for efficient power dissipation.

Feature Summary

• Hermetically sealed welded construction with internal solder bond design
• Standard polarity configuration with anode connected to the case
• Capable of operating at maximum rated power dissipation of 50 watts
• Qualified per MIL-PRF-19500/114 for JAN, JANTX, and JANTXV reliability levels

Applications

• Voltage regulation over broad ranges of operating current and temperature
• High-power protection circuits requiring robust thermal performance
• Radiation-hardened applications due to inherent radiation hardness properties

Procurement Notes

Verify that the specific ordering suffix matches the required military qualification level (JAN, JANTX, or JANTXV) as availability varies by part number. Confirm the polarity requirement, noting that standard units have the anode to the case while reverse polarity options exist with different suffixes. Ensure proper mounting hardware and heat sinking are selected to support the 50W power dissipation rating within the specified junction temperature range.

Selection Notes

Select this component when a high-power 50W Zener diode with precise voltage regulation is required. The 20V nominal voltage with 5% tolerance suits applications needing stable reference voltages under varying loads. Consider the TO-204AD package for through-hole mounting and high thermal capacity. Evaluate the need for military-grade reliability qualifications if operating in harsh environments.

Part Context

This component is part of the broader 1N2804B–1N2846B and 1N4557B–1N4564B family of 50W Zener diodes manufactured by Microsemi, now part of Microchip Technology. The series covers a wide voltage range from 3.9V to 200V, providing versatile options for high-power regulation needs across various industrial and aerospace sectors.

Replacement Considerations

Direct substitutes include other members of the 1N28xxB series with matching voltage ratings. Verify compatibility regarding package dimensions, thermal resistance, and military qualification levels when replacing.