1N4909

Overview

The Microchip Technology 1N4909 is a temperature-compensated Zener reference diode designed for precision voltage regulation applications. It features a nominal Zener voltage of 12.8 V with a tight tolerance of ±5%. The device operates in the DO-35 axial through-hole package and dissipates up to 500 mW of power. Key electrical characteristics include a maximum reverse leakage current of 15 µA at 8 V, a Zener impedance of 50 Ohms, and a low voltage temperature coefficient of 0.01 %/°C. It supports an extended operating temperature range from -65°C to +175°C.

Feature Summary

• Temperature compensation design ensures stable voltage output across wide thermal variations
• Low noise performance suitable for sensitive reference circuits
• High reliability construction with hermetic sealing options available

Applications

• Precision voltage reference sources
• Temperature compensated regulator circuits
• Low noise analog signal conditioning

Procurement Notes

Verify RoHS compliance status as standard versions may not meet current environmental directives. Confirm package type availability, noting that hermetically sealed variants exist under specific suffixes. Cross-reference datasheet specifications for exact test conditions regarding leakage current and impedance values before finalizing procurement.

Selection Notes

Select this component when high stability over temperature is required compared to standard Zener diodes. Ensure the circuit can handle the specified 500 mW power dissipation. Verify that the 12.8 V nominal voltage aligns with system requirements. Consider hermetic packages if operating in harsh environments requiring radiation or moisture resistance.

Part Context

This part belongs to the industry-standard 1N49xx series of temperature-compensated Zener diodes. It serves as a direct replacement for similar devices from other manufacturers like Microsemi or CDI Diode. The 12.8 V rating places it in a common mid-range category for precision references within the series.

Replacement Considerations

Equivalent parts include CDLL4909 (surface mount) and 1N4909A. Check manufacturer-specific datasheets for pinout compatibility and exact parameter tolerances before substitution.