onsemi 2N3704

Overview

2N3704 from Fairchild Semiconductor is an NPN epitaxial silicon transistor designed for general-purpose amplification and switching in low-to-medium power circuits, with V_CEO = 30 V, I_C = 500 mA continuous, h_FE = 100–300 at 50 mA, f_T = 100 MHz, and TO-92 package. It serves as a discrete gain stage or saturated switch in analog signal conditioning and digital logic interfacing.

For engineers reviewing the 2N3704 datasheet, pinout, applications, or equivalent options, key selection considerations include DC current gain linearity at 50 mA, saturation voltage under 100 mA/5 mA drive, thermal resistance (R_θJA = 200 °C/W), and compatibility with through-hole PCB layouts requiring lead-forming per TO-92 mechanical drawing.

Technical Context

The 2N3704 operates as a single NPN bipolar junction transistor optimized for linear amplification and hard-switching roles. Its h_FE range (100–300) supports stable biasing across production lots, while V_CE(sat) ≤ 1.0 V at I_C = 100 mA / I_B = 5 mA enables efficient on-state conduction in relay drivers and LED switches.

Thermal design relies on R_θJA = 200 °C/W and P_D = 625 mW at 25°C, derating 5.0 mW/°C above ambient. The device meets JEDEC TO-92 mechanical standards with emitter-collector-base pinout (1–2–3), and its f_T = 100 MHz supports audio-frequency amplification and low-speed digital edge shaping.

Key Specifications

Pinout & Package

2N3704 is housed in a standard JEDEC TO-92 plastic package with 3 leads, lead spacing 1.27 mm, body length 4.58 mm, and defined pinout: Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2N3704, the 2N2222A offers higher voltage headroom and power handling, while the BC547B trades current capability for tighter h_FE control-making each optimal for distinct trade-offs between robustness, efficiency, and signal fidelity.

Availability

2N3704 is available at Aetrix Electronics and suitable for audio signal conditioning, microcontroller peripheral interfacing, linear regulator feedback loops, and industrial sensor buffering requiring stable component supply and long-term obsolescence management.

Supply support for 2N3704 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 devices before its acquisition by ON Semiconductor in 2016.

The 2N3704 belongs to Fairchild's legacy general-purpose bipolar transistor family, engineered for cost-effective, reliable amplification and switching in consumer, industrial, and automotive-adjacent electronics.

FAQ

What is the maximum collector-emitter voltage rating for the 2N3704?

The 2N3704 has a maximum collector-emitter voltage (V_CEO) rating of 30 V at T_A = 25°C. This value is absolute-exceeding it risks irreversible junction breakdown. Derating is not specified beyond temperature effects, and operation above 30 V requires verification against transient conditions and safety margins per application.

Does the 2N3704 support switching applications, and what base drive is needed?

Yes, the 2N3704 is qualified for switching use with V_CE(sat) ≤ 1.0 V at I_C = 100 mA and I_B = 5 mA. For reliable saturation, apply ≥5 mA base current-achievable via a 1 kΩ resistor from a 5 V logic source. Avoid open-base conditions during switching transitions to prevent unintended conduction.

What is the thermal resistance and power dissipation limit of the 2N3704?

The 2N3704 has R_θJA = 200 °C/W and P_D = 625 mW at 25°C, derating linearly by 5.0 mW/°C above that ambient. At 50°C ambient, max dissipation drops to 500 mW. PCB copper area and airflow significantly affect real-world thermal performance-no external heatsink is required below 300 mW in still air.

How does the 2N3704 compare to the PN100 referenced in its datasheet?

The PN100 shares the same Process 10 fabrication as the 2N3704 and exhibits nearly identical electrical characteristics, including V_CEO, h_FE, and f_T. However, the PN100 is specified for higher-reliability industrial use with tighter parameter screening and extended temperature validation-making it a drop-in alternative where enhanced lot traceability or MIL-STD screening is mandated.

Is the 2N3704 RoHS-compliant and lead-free?

The original 2N3704 (Rev. B, July 2002) predates RoHS enforcement and uses leaded solder-compatible packaging. Current production equivalents from ON Semiconductor (which acquired Fairchild) may offer RoHS-compliant versions-verify compliance status using the specific date code and ordering part number, as legacy 2N3704 reels are not inherently RoHS-conforming.