1N4918A

Overview

The Microchip Technology 1N4918A is a temperature-compensated Zener reference diode designed for precision voltage regulation applications. It features a nominal Zener voltage of 19.2 V with a tight tolerance of ±5%. The device supports a maximum DC power dissipation of 500 mW at +50°C, with a derating factor of 4 mW/°C above this threshold. It utilizes a DO-35 axial through-hole package and exhibits a maximum Zener impedance (Zzt) of 600 Ohms. The component operates within an extended temperature range from -55°C to +100°C, ensuring stability in demanding environments.

Feature Summary

• Temperature compensated design ensures stable voltage reference performance across varying thermal conditions.
• Low noise characteristics provide clean regulation suitable for sensitive analog circuits.
• Metallurgically bonded construction with double plug assembly enhances mechanical reliability and longevity.

Applications

• Precision voltage reference sources in measurement instrumentation
• Temperature compensated regulator circuits requiring stable bias voltages
• Low noise power supply filtering and stabilization

Procurement Notes

Verify the specific suffix and packaging configuration against the official datasheet before ordering. Confirm that the required operating temperature range aligns with the specified -55°C to +100°C limit. Ensure the circuit design accounts for the 500 mW power dissipation rating and appropriate derating factors. Cross-reference the manufacturer part number to avoid confusion with similar general-purpose Zener diodes lacking temperature compensation.

Selection Notes

Select the 1N4918A when a stable 19.2 V reference is required with minimal drift over temperature changes. Consider its low noise profile for applications where signal integrity is critical. Evaluate the DO-35 package constraints for PCB layout and mounting requirements. Compare the 600 Ohm impedance against load variations to ensure adequate regulation performance under expected current loads.

Part Context

This component belongs to the 1N4916 through 1N4932A series of temperature-compensated Zener reference diodes manufactured by Microchip Technology. These devices are engineered to provide superior voltage stability compared to standard Zener diodes, particularly in the lower voltage ranges where temperature coefficients can be significant. The series is widely used in industrial and commercial electronics requiring reliable reference voltages.

Replacement Considerations

Consult official substitution guides for equivalent temperature-compensated Zener diodes with matching 19.2 V nominal voltage and ±5% tolerance. Verify that any alternative part maintains comparable low-noise specifications and metallurgical bonding quality. Ensure the replacement fits the DO-35 package and meets the same power dissipation and temperature ratings.

FAQ

What is the primary advantage of the 1N4918A over standard Zener diodes?

The 1N4918A is temperature compensated, providing significantly better voltage stability across varying temperatures compared to standard Zener diodes.

How does the power dissipation change with temperature?

The device supports 500 mW at +50°C, with power derating applied at a rate of 4 mW per degree Celsius above +50°C.