1N5518B

Overview

The Microchip Technology 1N5518B is a low voltage avalanche Zener diode rated at 0.5 W, housed in an axial-lead glass DO-35 (DO-204AH) package. It provides a nominal Zener voltage of 3.3 V with a tight tolerance of ±5%. The device operates within a junction temperature range of -65°C to +175°C and features a maximum reverse leakage current of 5 µA at 3 V. Electrical characteristics include a test current of 20 mA, a maximum dynamic impedance of 26 Ohms, and a forward voltage of 1.1 V at 200 mA.

Feature Summary

• Provides stable voltage regulation across a broad operating current and temperature range.
• Features hermetically sealed glass construction for environmental protection.
• Offers minimal capacitance suitable for high-frequency applications.
• Inherently radiation hard without requiring special processing.

Applications

• Voltage regulation circuits
• Reference voltage sources
• Overvoltage protection

Procurement Notes

Verify the specific suffix requirements against your design specifications. Confirm whether the standard bond or metallurgical bond option is required for your application. Ensure that the chosen packaging format aligns with your assembly process capabilities. Check for RoHS compliance status if mandated by your project standards. Validate all electrical parameters against the official datasheet before finalizing procurement.

Selection Notes

Select this component when a precise 3.3 V reference is needed with strict tolerance limits. Consider the DO-35 package dimensions for board layout constraints. Evaluate the thermal resistance values for heat dissipation planning. Compare the noise density specifications against circuit sensitivity requirements. Assess the operating temperature range against environmental conditions.

Part Context

This part belongs to the 1N5518 through 1N5546 series of low voltage avalanche Zener diodes. The series covers a voltage selection from 3.3 to 33 volts. Variants are available with different voltage tolerances ranging from ±1% to ±20%. Military qualifications such as JAN, JANTX, and JANTXV are also offered for specialized applications.

Replacement Considerations

Direct replacements must match the 3.3 V nominal voltage, ±5% tolerance, and 0.5 W power rating. Verify compatibility with the DO-35 axial lead package. Ensure equivalent thermal and electrical performance characteristics are maintained.

FAQ

What does the 'B' suffix indicate for this part number?

The 'B' suffix indicates a Zener voltage tolerance of plus/minus 5 percent.

Is this component qualified for military standards?

Yes, variants of this series are qualified per MIL-PRF-19500/437 for JAN, JANTX, and JANTXV levels.

How is polarity identified on the package?

Polarity is indicated by a band on the diode body; the banded end represents the cathode.