onsemi 2N5401_D28Z

Overview

2N5401_D28Z from Fairchild Semiconductor is a PNP epitaxial silicon small-signal transistor rated for -150 V V_CEO, -600 mA I_C, and 625 mW P_C, optimized for high-voltage amplification and switching in discrete analog circuits such as active filters, voltage regulators, and relay drivers.

For engineers reviewing the 2N5401_D28Z datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CEO = -150 V, h_FE = 30–240 at I_C = -1 to -50 mA, f_T = 100–400 MHz, V_CE(sat) ≤ -0.5 V at I_C = -50 mA, and TO-92 package compatibility with legacy through-hole designs.

Technical Context

The 2N5401_D28Z operates as a general-purpose PNP bipolar junction transistor with fixed emitter-base and collector-base breakdown limits (-5 V and -160 V respectively), enabling stable operation in linear amplification and saturated switching modes up to 150°C junction temperature. Its low noise figure (8 dB at 10 Hz–15.7 kHz) and controlled Cob (6 pF at V_CB = -10 V) support audio-frequency and medium-speed digital interface applications.

DC current gain varies predictably across collector current: h_FE ≥ 30 at I_C = -1 mA, ≥ 60 at I_C = -10 mA, and ≥ 50 at I_C = -50 mA, all measured at V_CE = -5 V - confirming consistent gain behavior across its intended bias range without thermal runaway under standard test conditions.

Key Specifications

Pinout & Package

2N5401_D28Z is housed in a standard TO-92 plastic package with 3 leads, compatible with manual soldering and wave soldering processes. Lead identification follows the "Emitter-Base-Collector" sequence when viewing the flat side of the package with leads pointing downward.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP small-signal transistor applications.

Compared with MPSA92 and BC557B, the 2N5401_D28Z uniquely balances -150 V blocking, 625 mW dissipation, and broad h_FE range - making it optimal for mid-voltage industrial controls and legacy audio designs where both voltage headroom and gain predictability matter.

Availability

2N5401_D28Z is available at Aetrix Electronics and suitable for industrial control systems, legacy audio equipment repair, and discrete power supply design requiring stable component supply and long-term obsolescence mitigation.

Supply support for 2N5401_D28Z includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Fairchild Semiconductor was a U.S.-based semiconductor manufacturer specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The 2N5401_D28Z belongs to Fairchild's legacy general-purpose transistor family designed for reliability-critical analog and switching applications in industrial, automotive, and consumer electronics.

FAQ

What is the maximum collector-emitter voltage rating for the 2N5401_D28Z?

The 2N5401_D28Z has a guaranteed minimum collector-emitter breakdown voltage (BV_CEO) of -150 V at I_C = -1 mA and I_B = 0. This rating is validated per Fairchild's Rev. B datasheet and applies under continuous DC conditions at T_A = 25°C. Derating is required above 25°C ambient per the specified thermal resistance curve.

Does the 2N5401_D28Z have a documented noise figure specification?

Yes, the 2N5401_D28Z has a published noise figure of 8 dB, measured at I_C = -250 µA, V_CE = -5 V, R_S = 1 kΩ, and frequency range 10 Hz to 15.7 kHz. This value appears in the "Electrical Characteristics" table of the official Fairchild datasheet and reflects its suitability for low-noise analog signal amplification.

What is the pin configuration of the 2N5401_D28Z in its TO-92 package?

The 2N5401_D28Z uses the standard TO-92 package with Emitter-Base-Collector (E-B-C) pinout: Lead 1 = Emitter, Lead 2 = Base, Lead 3 = Collector when viewed from the flat side with leads pointing downward. This matches the "suffix -C" notation in Fairchild documentation indicating counter-collector orientation.

Can the 2N5401_D28Z be used in switching applications?

Yes, the 2N5401_D28Z is qualified for switching use with V_CE(sat) ≤ -0.5 V at I_C = -50 mA and I_B = -5 mA, and f_T up to 400 MHz. Its fast turn-on/turn-off characteristics and low saturation voltage make it appropriate for medium-speed (<1 MHz) discrete switching in power supplies, relay drivers, and logic level shifters.

Is the 2N5401_D28Z RoHS compliant?

The 2N5401_D28Z was originally manufactured prior to mandatory RoHS implementation and is not certified RoHS compliant per EU Directive 2011/65/EU. Aetrix Electronics provides full material declaration documentation upon request and can advise on compliant alternatives such as the ON Semiconductor NSS12201LT1G if regulatory compliance is required.