onsemi 2N3704_D74Z

Overview

2N3704_D74Z 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 I_C = 50 mA, V_CE(sat) ≤ 1.0 V at I_C = 100 mA, and TO-92 package. It operates across –55 °C to +150 °C and supports applications such as signal buffering in audio preamps and digital logic-level switching.

For engineers reviewing the 2N3704_D74Z datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain range, saturation voltage under defined drive conditions, thermal resistance (R_θJA = 200 °C/W), maximum collector-emitter breakdown voltage, and TO-92 mechanical compatibility in space-constrained PCB layouts.

Technical Context

The 2N3704_D74Z is a discrete NPN bipolar junction transistor fabricated using Fairchild's Process 10. Its operation relies on forward-active mode biasing with base-emitter junction forward-biased and collector-base junction reverse-biased, enabling linear amplification or saturated switching based on external resistor network design.

It exhibits f_T = 100 MHz and C_ob = 12 pF at V_CB = 10 V, f = 1 MHz, supporting medium-frequency small-signal amplification up to ~10 MHz in optimized common-emitter configurations. Thermal derating begins above 25 °C at 5.0 mW/°C, with R_θJC = 83.3 °C/W confirming case-mounted heat path efficiency.

Key Specifications

Pinout & Package

2N3704_D74Z is housed in a TO-92 plastic package with standard lead configuration: leads aligned vertically when viewed with flat side facing outward and leads down. Package outline conforms to JEDEC TO-92 variant with 3.60 ± 0.20 mm body width and 14.47 ± 0.40 mm overall length.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2N3704_D74Z, the 2N2222A offers greater voltage and power margins for robustness in variable-supply systems, while the BC547B delivers higher gain consistency at lower currents-making each suitable where those specific trade-offs align with circuit requirements.

Availability

2N3704_D74Z is available at Aetrix Electronics and suitable for audio signal conditioning, microcontroller interface buffering, discrete oscillator circuits, and low-power switching applications requiring stable component supply and long-term manufacturability.

Supply support for 2N3704_D74Z 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 2N3704_D74Z belongs to Fairchild's legacy general-purpose NPN transistor family, engineered for cost-effective, reliable amplification and switching in consumer, industrial, and educational electronics.

FAQ

What is the maximum continuous collector current rating for the 2N3704_D74Z?

The 2N3704_D74Z 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. Operation beyond this limit risks thermal instability or permanent damage, especially without adequate PCB copper area for heat spreading.

Does the 2N3704_D74Z have a specified transition frequency (f_T)?

Yes, the 2N3704_D74Z has a specified transition frequency (f_T) of 100 MHz, measured at I_C = 50 mA and V_CE = 2.0 V. This parameter confirms its suitability for small-signal amplification up to approximately 10 MHz in practical common-emitter configurations with appropriate biasing and layout.

What is the pin configuration of the 2N3704_D74Z in its TO-92 package?

The 2N3704_D74Z uses the standard TO-92 pinout: Pin 1 is Emitter, Pin 2 is Collector, and Pin 3 is Base-when viewed with the flat side facing outward and leads pointing downward. This configuration is consistent across Fairchild's 2N3704 variants and matches industry-standard TO-92 orientation for manual assembly and schematic symbol alignment.

Is the 2N3704_D74Z suitable for switching inductive loads like relays?

Yes, the 2N3704_D74Z is suitable for switching inductive loads such as relays, provided a flyback diode is used across the coil. Its V_CEO = 30 V and V_CBO = 50 V provide margin against inductive kickback, and its I_C = 500 mA rating supports typical relay coils drawing <300 mA. Ensure base drive meets h_FE-based requirements for full saturation.

What is the thermal resistance from junction to ambient (R_θJA) for the 2N3704_D74Z?

The thermal resistance from junction to ambient (R_θJA) for the 2N3704_D74Z is 200 °C/W under standard test conditions (T_A = 25 °C, no heatsink, on FR-4 board with minimal copper). This value allows direct junction temperature estimation using T_J = T_A + (P_D × R_θJA), critical for reliability validation in sustained switching or linear operation.