2N5540

Overview

The Microchip Technology 2N5540 is a PNP bipolar junction transistor designed for general-purpose amplification and switching applications. It features a collector-emitter breakdown voltage of 160 V and a continuous collector current rating of 800 mA. The device operates within a junction temperature range of -65°C to +200°C, ensuring reliability in demanding environments. Packaged in the TO-92 (TO-226AA) through-hole format, it provides a DC current gain (hFE) ranging from 100 to 700 at specified test conditions. This component is suitable for use in audio circuits, signal processing, and low-power control systems where robust performance is required.

Feature Summary

• High junction temperature capability up to 200°C for extended thermal operation
• Wide DC current gain range supporting diverse amplification requirements
• Robust 160 V collector-emitter breakdown voltage for high-voltage switching
• Through-hole TO-92 package for standard PCB mounting

Applications

• General-purpose analog signal amplification
• Low-power switching circuits
• Audio pre-amplifier stages
• Temperature-compensated oscillator circuits

Procurement Notes

Verify the specific manufacturer lot code and date code upon receipt to ensure compliance with project timelines. Confirm that the received components match the exact 2N5540 specification sheet parameters, particularly hFE binning if critical. Inspect leads for straightness and solderability before assembly. Ensure storage conditions prevent moisture absorption, although this leaded package is less sensitive than surface-mount variants. Validate that the supplier provides traceable documentation for quality assurance purposes.

Selection Notes

Select the 2N5540 when a PNP transistor with moderate current handling and high voltage tolerance is needed in a through-hole configuration. Compare its 800 mA limit against load requirements to avoid saturation issues. Consider the TO-92 package size constraints relative to available board space. Evaluate the thermal resistance characteristics if operating near maximum power dissipation limits. Ensure the application does not require the higher current capabilities of larger packages like TO-220.

Part Context

The 2N5540 belongs to the legacy military-grade and commercial PNP transistor family produced by Microchip Technology. It serves as a direct replacement for older 2N5540 equivalents from other manufacturers, maintaining pinout compatibility. The device is part of Microchip's extensive discrete semiconductor portfolio, focusing on reliability for industrial and aerospace applications. Its long-term availability supports designs requiring stable supply chains for non-obsolescent components.

Replacement Considerations

Direct substitutes include the 2N5401 (NPN counterpart, different polarity), MPSA42, or BC560 series PNP transistors. Verify pinout alignment and electrical parameter overlaps, specifically Vceo and Ic ratings. Check if the alternative package matches the TO-92 form factor for mechanical fit. Ensure the replacement meets the same thermal and gain specifications for circuit functionality.