onsemi PN3642_D26Z

Overview

PN3642_D26Z from Fairchild Semiconductor is an NPN general-purpose bipolar junction transistor (BJT) designed for amplification and switching in low-to-medium power circuits, with V_CEO = 45 V, I_C = 500 mA continuous, h_FE = 40–120 at I_C = 150 mA, and TO-92 package. It serves in audio preamplifiers, relay drivers, and signal conditioning stages where moderate gain and fast turn-on are required.

For engineers reviewing the PN3642_D26Z datasheet, pinout, applications, or equivalent options, key selection criteria include its 45 V V_CEO, 500 mA I_C rating, 0.22 V V_CE(sat) at I_C/I_B = 150 mA/15 mA, 8.0 pF C_ob, and suitability for linear amplification up to 100 MHz.

Technical Context

This NPN BJT operates with a maximum junction temperature of 150°C and thermal resistance R_θJA = 200°C/W, enabling use in ambient temperatures up to 65°C under derated power conditions. Its DC current gain h_FE varies from 40 (min) at I_C = 150 mA to 15 (min) at I_C = 500 mA, reflecting typical gain compression at higher currents.

The device exhibits small-signal current gain h_fe = 1.5 at f = 100 MHz, V_CE = 5.0 V, and I_C = 50 mA, and delivers 10 dB amplifier power gain (G_pe) at 30 MHz with 60% collector efficiency under matched RF conditions - confirming utility beyond DC switching into RF amplification roles.

Key Specifications

Pinout & Package

PN3642_D26Z is housed in a standard through-hole TO-92 package (3-lead, epoxy molded), with lead spacing matching JEDEC TO-92 outline. The package provides adequate thermal performance for low-duty-cycle or thermally managed PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBT3904LT1G and BC547B, PN3642_D26Z uniquely balances 500 mA I_C, 45 V V_CEO, and TO-92 through-hole compatibility - making it optimal for legacy industrial controls and medium-power linear circuits where SMT conversion is not feasible.

Availability

PN3642_D26Z is available at Aetrix Electronics and suitable for audio preamplifiers, relay drivers, and RF oscillator circuits requiring stable component supply and long-term obsolescence management.

Supply support for PN3642_D26Z 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.

PN3642_D26Z belongs to Fairchild's legacy general-purpose BJT product line, engineered for cost-sensitive, reliability-critical linear and switching applications in industrial, consumer, and communications equipment.

FAQ

What is the maximum continuous collector current rating for PN3642_D26Z?

PN3642_D26Z has a maximum continuous collector current (I_C) rating of 500 mA at T_A = 25°C. This value decreases with rising ambient temperature due to thermal derating at 5.0 mW/°C above 25°C, and operation must remain within the 625 mW total power dissipation limit. PN3642_D26Z is rated for sustained 500 mA loads only when adequately heatsinked or operated in controlled thermal environments.

Does PN3642_D26Z support RF amplification applications?

Yes, PN3642_D26Z supports RF amplification up to 100 MHz, evidenced by its h_fe = 1.5 at f = 100 MHz and verified 10 dB amplifier power gain (G_pe) at 30 MHz. PN3642_D26Z achieves 60% collector efficiency under matched RF conditions, confirming suitability for VHF oscillator and low-power RF amplifier stages when properly biased and impedance-matched.

What is the pin configuration of PN3642_D26Z in the TO-92 package?

PN3642_D26Z uses the standard TO-92 pinout: Pin 1 is Emitter, Pin 2 is Base, and Pin 3 is Collector - with leads arranged left-to-right when viewing the flat side of the package with leads pointing downward. PN3642_D26Z maintains full mechanical and electrical compatibility with JEDEC TO-92 footprint dimensions, including 1.27 mm lead spacing and 3.60 mm body width.

Is PN3642_D26Z suitable for switching 12 V relay coils?

Yes, PN3642_D26Z is well-suited for switching 12 V relay coils drawing up to 500 mA. With V_CE(sat) = 0.22 V at I_C/I_B = 150 mA/15 mA, PN3642_D26Z limits power loss to under 33 mW in saturation, eliminating need for heatsinking in typical industrial relay driver designs operating at ambient temperatures ≤65°C.

What is the operating junction temperature range for PN3642_D26Z?

PN3642_D26Z has a specified operating and storage junction temperature range of –55°C to +150°C, with absolute maximum ratings based on a 150°C junction limit. Thermal resistance R_θJA = 200°C/W means that at 25°C ambient and 625 mW dissipation, junction temperature reaches exactly 150°C - so real-world use requires derating or thermal management to stay within safe limits. PN3642_D26Z must be operated below this threshold to ensure long-term reliability.