onsemi PN4250_D27Z

Overview

PN4250_D27Z from Fairchild Semiconductor is a PNP general-purpose bipolar junction transistor (BJT) designed for amplification and switching in low-to-medium power circuits, with V_CEO = 40 V, I_C = 500 mA continuous, h_FE = 250–700 at I_C = 100 µA, and TO-92 package. It serves in signal conditioning, discrete logic interfacing, and load switching up to 300 mA collector current.

For engineers reviewing the PN4250_D27Z datasheet, pinout, applications, or equivalent options, key selection considerations include its PNP polarity, DC current gain range, saturation voltage under defined drive conditions, thermal resistance (R_θJA = 200 °C/W), and TO-92 mechanical compatibility with legacy through-hole layouts.

Technical Context

The PN4250_D27Z operates as a silicon PNP BJT fabricated on Fairchild's Process 68, optimized for general-purpose linear amplification and saturated switching. Its electrical behavior is defined by base-emitter forward biasing, collector-emitter reverse-blocking capability up to 40 V, and predictable h_FE variation across I_C = 100 µA–10 mA.

It exhibits low noise figure (2.0 dB at 1 kHz, 250 µA), small-signal parameters including C_ob = 6.0 pF and h_ie = 6.0–20 kΩ, and specified cutoff currents (I_CBO ≤ 10 nA, I_EBO ≤ 20 nA), confirming suitability for stable biasing in analog front-ends and discrete gain stages.

Key Specifications

Pinout & Package

PN4250_D27Z is supplied in the standard TO-92 plastic package (3-lead, straight lead form, no lead clip), with pin 1 = Emitter, pin 2 = Base, pin 3 = Collector - confirmed per Fairchild's TO-92 Tape and Reel Data (Rev. B1, March 2001), Figure 2.0 "Style E", EOL code D27Z.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose amplifier and switching applications.

Compared with MPSA92 and BC557, PN4250_D27Z offers balanced 40 V/500 mA capability with verified 250–700 h_FE and 2.0 dB noise performance-making it optimal for medium-current, low-noise, general-purpose PNP roles where both gain and power handling matter.

Availability

PN4250_D27Z is available at Aetrix Electronics and suitable for relay driver circuits, LED current sinks, discrete logic level shifters, and low-noise audio preamplifiers requiring stable component supply and long-term obsolescence management.

Supply support for PN4250_D27Z 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 company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The PN4250_D27Z belongs to Fairchild's legacy general-purpose bipolar transistor product line, engineered for cost-effective, reliable amplification and switching in consumer, industrial, and automotive-adjacent electronics.

FAQ

What is the pin configuration of PN4250_D27Z?

PN4250_D27Z uses the standard TO-92 package with pin 1 = Emitter, pin 2 = Base, pin 3 = Collector - confirmed in Fairchild's TO-92 Tape and Reel Data (Rev. B1) for EOL code D27Z, Style "E". This configuration is consistent across all D27Z-packaged units of PN4250_D27Z and must be observed for correct PCB layout and functional operation.

Does PN4250_D27Z support switching applications up to 300 mA?

Yes, PN4250_D27Z is explicitly rated for collector currents up to 300 mA in switching applications, as stated in its original product description. Its absolute maximum I_C is 500 mA continuous, and V_CE(sat) ≤ 0.25 V at I_C = 10 mA ensures low-loss operation - making PN4250_D27Z suitable for driving relays, solenoids, and LED arrays within this current range.

What is the typical noise figure of PN4250_D27Z and under what conditions is it measured?

The PN4250_D27Z has a noise figure of 2.0 dB, measured at V_CE = 5.0 V, I_C = 250 µA, R_S = 1.0 kΩ, f = 1.0 kHz, and BW = 150 Hz. This value is documented in the "SMALL SIGNAL CHARACTERISTICS" section of the official datasheet and confirms PN4250_D27Z's suitability for low-noise analog amplification tasks.

Is PN4250_D27Z RoHS compliant?

PN4250_D27Z was manufactured prior to full RoHS enforcement and predates Fairchild's formal RoHS transition. The original datasheet and packaging documentation do not declare RoHS compliance. For new designs requiring RoHS adherence, consult Aetrix Electronics for qualified drop-in alternatives or verify compliance status via ON Semiconductor's legacy part cross-reference tools.

What thermal derating applies to PN4250_D27Z above 25°C ambient?

PN4250_D27Z has a total device dissipation (P_D) of 625 mW at T_A = 25°C, with a derating factor of 5.0 mW/°C above that temperature. This means usable power dissipation decreases linearly - e.g., to 500 mW at 50°C ambient - and must be applied alongside R_θJA = 200 °C/W to ensure junction temperature remains below 150°C in real-world layouts.