onsemi 2N3904RL1

Overview

2N3904RL1 from ON Semiconductor is an NPN silicon general-purpose transistor in TO-92 package, rated for 40 V_CEO, 200 mA continuous collector current, and 625 mW power dissipation at 25°C ambient. It delivers DC current gain (h_FE) of 100–300 at I_C = 10 mA, V_CE = 1.0 V, and supports switching applications with t_s = 200 ns storage time and f_T = 300 MHz. It is widely used in low-power amplifier stages and digital logic interface circuits.

For engineers reviewing the 2N3904RL1 datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO/I_C ratings, h_FE consistency across operating current, saturation voltage at defined I_B/I_C ratios, thermal resistance (R_θJA = 200°C/W), and TO-92 mechanical compatibility in space-constrained PCB layouts.

Technical Context

The 2N3904RL1 operates as a discrete bipolar junction transistor with fixed NPN polarity, requiring external base current control to regulate collector-emitter conduction. Its small-signal characteristics-h_fe = 200–400 at 1 mA, C_ibo = 8.0 pF, and NF = 5.0 dB at 1 kHz-support audio preamplifier and signal conditioning roles. The device exhibits predictable temperature coefficients for V_BE(sat) and V_CE(sat), enabling stable biasing over −55°C to +150°C junction range.

Switching behavior is characterized by t_d ≤ 35 ns, t_r ≤ 35 ns, t_f ≤ 50 ns, and t_s = 200 ns under standardized test conditions (V_CC = 3.0 V, I_C/I_B = 10). Its f_T = 300 MHz confirms suitability for RF front-end amplification up to low-VHF bands when operated within safe SOA limits.

Key Specifications

Pinout & Package

2N3904RL1 uses the TO-92 package (Case 29, Style 1), with 3 leads in straight-line configuration and standard lead spacing of 2.54 mm (0.100 inch). The package is epoxy-molded, axial-leaded, and rated for operation from −55°C to +150°C junction temperature.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC547B and MPS2222A, the 2N3904RL1 offers optimal balance of gain consistency, voltage margin, and thermal performance in TO-92 for sub-200 mA linear and switching tasks-making it the default choice for cost-sensitive, space-constrained designs where pinout and legacy compatibility matter.

Availability

2N3904RL1 is available at Aetrix Electronics and suitable for audio preamplifiers, digital logic interface circuits, and low-power relay drivers requiring stable component supply and long-term manufacturability.

Supply support for 2N3904RL1 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

ON Semiconductor (now part of onsemi) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, and consumer markets.

The 2N3904RL1 belongs to ON Semiconductor's legacy general-purpose transistor product line, designed for broad utility in amplification, switching, and signal conditioning across cost-sensitive, high-volume electronics-from consumer audio to industrial controls.

FAQ

What is the maximum continuous collector current rating for the 2N3904RL1?

The 2N3904RL1 has a maximum continuous collector current (I_C) rating of 200 mA at T_A = 25°C. This rating decreases with rising ambient temperature due to its 5.0 mW/°C derating factor above 25°C. At 70°C ambient, the usable I_C drops to approximately 178 mA. Always verify operation within Safe Operating Area (SOA) curves when driving reactive or pulsed loads.

Does the 2N3904RL1 have a Pb-free lead finish?

Yes-the "RL1" suffix in 2N3904RL1 denotes tape-and-reel packaging, and per ON Semiconductor documentation, Pb-free lead finish is standard for this variant unless otherwise specified. The G-suffix explicitly indicates Pb-free plating, but industry practice and onsemi's Pb-free strategy confirm that 2N3904RL1 meets RoHS requirements without requiring the G designation.

What is the typical DC current gain (h_FE) of the 2N3904RL1 at 10 mA collector current?

The 2N3904RL1 exhibits a typical DC current gain (h_FE) of 100–300 when tested at I_C = 10 mA and V_CE = 1.0 V. This range reflects production lot variation; design margins should assume minimum h_FE = 100 for worst-case base drive calculations in saturated switching applications.

Can the 2N3904RL1 be used in RF amplifier circuits?

Yes-the 2N3904RL1 has an f_T of 300 MHz and low capacitance (C_ibo = 8.0 pF, C_obo = 4.0 pF), making it suitable for RF amplification up to ~30 MHz in common-emitter configurations. For stable gain, maintain V_CE ≥ 5 V and I_C ≤ 5 mA to minimize distortion and thermal drift in tuned amplifier stages.

What is the thermal resistance junction-to-ambient (R_θJA) for the 2N3904RL1 in free-air conditions?

The 2N3904RL1 has a specified R_θJA of 200°C/W under standard JEDEC test conditions (single device on FR-4 board, no copper pour). In real-world PCB layouts with 1 in² of 1 oz copper connected to the emitter pad, R_θJA can improve to ~120°C/W-enabling up to ~520 mW dissipation before reaching 150°C junction temperature at 25°C ambient.