1N2818BU3/TR

Overview

The Microchip Technology 1N2818BU3/TR is a high-power 50 W Zener diode from the JEDEC registered 1N2804B through 1N2846B series. It provides voltage regulation with a nominal Zener voltage of 19 V at a test current of 660 mA. The device features a maximum dynamic impedance of 2.2 Ohms and operates within a junction temperature range of -65°C to +175°C. Packaged in a hermetically sealed TO-204AD (TO-3) case, it supports an average rated power dissipation of 50 W at a case temperature of 75°C or higher.

Feature Summary

• Hermetically sealed welded construction for reliable operation in harsh environments.
• Internal solder bond design ensures robust mechanical integrity under thermal stress.
• Standard polarity configuration connects the anode directly to the metal case.

Applications

• Voltage regulation across broad operating currents and temperatures
• High-power protection circuits requiring radiation hardness
• Military and aerospace systems utilizing MIL-PRF-19500/114 qualified components

Procurement Notes

Verify that the specific ordering suffix matches the required tolerance and polarity specifications. Confirm RoHS compliance status if environmental regulations apply, as commercial versions may differ from military qualifications. Ensure mounting hardware accommodates the TO-204AD package dimensions and thermal requirements for proper heat sinking.

Selection Notes

Select this component when a 19 V reference with high power handling capability is required. Consider the thermal resistance of 2.0°C/W and the need for adequate heat sinking to maintain junction temperatures within limits. Verify that the 10% voltage tolerance meets the circuit precision requirements compared to tighter tolerance options available in the family.

Part Context

This part belongs to the 1N2804B–1N2846B series of 50 Watt Zener diodes manufactured by Microchip Technology. The series offers a wide range of nominal voltages from 3.9 V to 200 V. These devices are designed for applications demanding high reliability and are often selected for their inherent radiation hardness and rugged TO-204AD packaging.

Replacement Considerations

Check for equivalent parts within the 1N28xxB series offering the same 19 V nominal voltage. Verify that any substitute maintains the TO-204AD package style and hermetic sealing characteristics. Ensure the replacement device meets the same MIL-PRF-19500/114 qualification levels if used in military or aerospace contexts.

FAQ

What is the standard polarity configuration for the 1N2818BU3/TR?

The standard polarity for this device is anode-to-case, meaning the anode terminal is internally connected to the metal case.

Is the 1N2818BU3/TR radiation hard?

Yes, these Zener diodes are inherently radiation hard as described in Microsemi MicroNote 050.