2N4427

Overview

The Central Semiconductor 2N4427 is a silicon NPN RF transistor designed for high-frequency amplifier applications. It features an epitaxial planar construction housed in a hermetically sealed TO-39 metal case. The device supports a maximum collector-base voltage of 40 V and a continuous collector current of 400 mA. Key electrical characteristics include a transition frequency (fT) of 500 MHz, a DC current gain (hFE) ranging from 10 to 200 at 100 mA, and a power dissipation capacity of 1.0 W at ambient temperature. The component operates within a junction temperature range of -65°C to +200°C.

Feature Summary

• Hermetically sealed TO-39 metal package ensures reliability in demanding environments
• Epitaxial planar silicon NPN construction optimized for RF performance
• High transition frequency capability suitable for microwave amplifier stages

Applications

• High frequency amplifier circuits
• Microwave signal processing
• RF oscillator designs

Procurement Notes

This component has been officially discontinued by the manufacturer and is currently classified as End of Life. Availability is restricted strictly to existing stock inventory; no further production orders can be accepted. Buyers must verify immediate stock availability through authorized representatives or distributors before committing to purchases. Replacement sourcing should be initiated promptly due to limited supply constraints.

Selection Notes

Engineers selecting this component must account for its discontinuation status when designing new systems. While the TO-39 package offers robust thermal and environmental sealing, alternative surface-mount or modern lead-free options may be required for long-term manufacturing sustainability. Verify that the specific lot meets all original electrical parameters, particularly hFE and fT, as these are critical for RF circuit stability.

Part Context

The 2N4427 belongs to the family of silicon NPN RF transistors manufactured using epitaxial planar processes. It is specifically engineered for high-frequency operation where low noise and high gain are required. The hermetic metal packaging distinguishes it from standard plastic-packaged equivalents, making it suitable for aerospace, military, or industrial applications requiring extended temperature resilience and moisture resistance.

Replacement Considerations

No direct replacement part numbers are provided by the manufacturer for the 2N4427. Designers must evaluate alternative RF transistors with similar TO-39 packaging, voltage ratings, and transition frequencies. Consultation with engineering support is recommended to identify compatible substitutes that meet the original circuit's impedance and gain requirements.