onsemi 2N5089BU

Overview

2N5089BU from ON Semiconductor is a low-noise, high-gain NPN bipolar junction transistor designed for general-purpose amplifier applications at collector currents from 1 µA to 50 mA. It features V_CEO = 25 V, V_CBO = 30 V, h_FE = 400–1200 (at I_C = 10 mA), f_T = 50 MHz, and NF = 2.0 dB (at I_C = 100 µA), commonly used in audio preamplifier stages and sensor signal conditioning circuits.

For engineers reviewing the 2N5089BU datasheet, pinout, applications, or equivalent options, key selection considerations include its low-noise performance at microamp bias, TO-92 package thermal resistance (R_θJA = 200 °C/W), DC current gain stability across temperature, and suitability for low-power analog front-ends requiring <100 mW dissipation.

Technical Context

The 2N5089BU operates as a single NPN BJT with fixed-emitter configuration and no integrated biasing or protection circuitry. Its small-signal h_fe reaches 450–1800 at 1 mA and 1 kHz, while pulsed h_FE maintains ≥400 up to 10 mA. The device exhibits C_cb = 4.0 pF and C_eb = 10 pF at specified reverse-bias conditions, supporting stable mid-band amplification without parasitic resonance.

Thermal design relies on its TO-92 package's R_θJA = 200 °C/W (free-air) and maximum T_J = +150 °C, enabling operation from –55 °C to +125 °C ambient when derated per PD = 625 mW at 25 °C. Noise performance is optimized for source impedances between 1 kΩ and 10 kΩ, with NF ≤ 2.0 dB confirmed at 100 µA and 10 Hz–15.7 kHz bandwidth.

Key Specifications

Pinout & Package

2N5089BU is housed in a standard TO-92 plastic package with 3 leads, rated for through-hole mounting and manual soldering. Lead finish is matte tin, compliant with RoHS and JEDEC J-STD-020 moisture sensitivity level (MSL) 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2N5089BU, 2N5088BU offers higher voltage ratings but sacrifices low-noise performance, while MMBT5089 matches electrical behavior in a smaller footprint but cannot sustain equivalent thermal loads-making 2N5089BU optimal for through-hole, low-noise, medium-power analog gain stages.

Availability

2N5089BU is available at Aetrix Electronics and suitable for audio preamplifier stages, temperature sensor interfaces, and industrial current sense amplifiers requiring stable component supply, long-term obsolescence planning, and full traceability.

Supply support for 2N5089BU 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 (Semiconductor Components Industries, LLC) is a global supplier of energy-efficient semiconductor components, specializing in power management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The 2N5089BU belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line, originally developed by Fairchild Semiconductor to deliver high-gain, low-noise amplification for cost-sensitive analog signal chains in consumer and industrial equipment.

FAQ

What is the maximum collector-emitter voltage rating for the 2N5089BU?

The 2N5089BU has a maximum collector-emitter voltage (V_CEO) rating of 25 V at T_A = 25 °C. This value is absolute-exceeding it risks avalanche breakdown and permanent device failure. Derating is not specified beyond the standard –55 °C to +150 °C junction temperature range, so design margins should maintain V_CE ≤ 20 V in production circuits using 2N5089BU.

Does the 2N5089BU have a documented noise figure specification?

Yes, the 2N5089BU has a verified noise figure (NF) of 2.0 dB at I_C = 100 µA, V_CE = 5.0 V, R_S = 10 kΩ, and f = 10 Hz to 15.7 kHz bandwidth. This value is measured and published in the official ON Semiconductor datasheet for 2N5089BU and is repeatable across production lots when test conditions are strictly followed.

What package type is used for the 2N5089BU?

The 2N5089BU uses the TO-92 through-hole plastic package with lead spacing of 0.1 inch (2.54 mm) and standard EIAJ outline. It is not offered in SMT variants-the surface-mount equivalent is the MMBT5089 in SOT-23, which shares electrical characteristics but differs in thermal performance and mounting method.

Can the 2N5089BU replace the 2N5088BU in an existing design?

The 2N5089BU can replace the 2N5088BU only if the circuit operates within its lower V_CEO (25 V vs. 30 V) and V_CBO (30 V vs. 35 V) limits. Gain and noise performance improve (h_FE up to 1200, NF = 2.0 dB), but voltage headroom decreases-verify all DC bias points and transient spikes stay below 25 V before substituting 2N5089BU for 2N5088BU.

Is the 2N5089BU suitable for high-frequency amplifier designs above 10 MHz?

The 2N5089BU supports small-signal amplification up to approximately 20 MHz with usable gain, based on its f_T = 50 MHz and measured h_fe = 450 at 10 MHz. However, layout parasitics, bias stability, and C_cb/C_eb become dominant above 10 MHz; for >30 MHz applications, dedicated RF transistors such as the MMBT918 or BFR92A are recommended instead of 2N5089BU.