onsemi 2N5087BU

Overview

2N5087BU from ON Semiconductor is a PNP general-purpose amplifier transistor optimized for low-level, high-gain, low-noise analog signal amplification at collector currents up to 50 mA. It delivers DC current gain (h_FE) of 250 at I_C = −1.0 mA, V_CE = −5.0 V; features V_CEO = −50 V, f_T = 40 MHz, and noise figure as low as 2.0 dB at I_C = −20 µA with R_S = 10 kΩ - enabling precision audio preamplifier and sensor interface stages.

For engineers reviewing the 2N5087BU datasheet, pinout, applications, or equivalent options, key selection criteria include its PNP polarity, TO-92 package mechanical compatibility, −50 V breakdown rating, low-noise performance below 3 dB across 10 Hz–15.7 kHz, and verified h_FE range of 250–800 under standard bias conditions.

Technical Context

This device operates in common-emitter configuration with guaranteed h_FE ≥ 250 at I_C = −1.0 mA and V_CE = −5.0 V, and supports linear amplification up to 40 MHz bandwidth. Its V_BE(on) = −0.85 V at I_C = −1.0 mA confirms predictable turn-on behavior for bias network design.

Thermal resistance R_θJA = 200 °C/W (TO-92) enables stable operation up to +150 °C junction temperature, while C_cb = 4.0 pF at V_CB = −5.0 V ensures minimal Miller capacitance in high-frequency gain stages.

Key Specifications

Pinout & Package

2N5087BU is housed in a through-hole TO-92 package with standardized lead assignment: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector. The package meets JEDEC TO-92 outline dimensions (14.47 mm × 4.58 mm × 3.86 mm max) and supports manual soldering and wave soldering per IPC-J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2N5086BU and MMBT5087, the 2N5087BU offers the highest guaranteed h_FE in the family and superior thermal dissipation in TO-92, making it optimal for gain-critical, thermally demanding analog stages where manual assembly or legacy through-hole compatibility is required.

Availability

2N5087BU is available at Aetrix Electronics and suitable for audio preamplifiers, sensor signal conditioners, and discrete voltage regulators requiring stable component supply, long-term obsolescence management, and full traceability from Fairchild/ON Semiconductor's qualified manufacturing line.

Supply support for 2N5087BU 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 (formerly Fairchild Semiconductor) is a global leader in intelligent power and sensing solutions, serving automotive, industrial, cloud computing, and consumer markets with energy-efficient semiconductor technologies.

The 2N5087BU belongs to Fairchild's legacy "FACT Quiet Series™" discrete transistor family, engineered specifically for low-noise, high-linearity analog amplification in cost-sensitive, high-reliability applications.

FAQ

What is the maximum collector current rating for the 2N5087BU?

The 2N5087BU has a continuous collector current rating of −100 mA. This value represents the absolute maximum DC current the device can sustain without exceeding its thermal or electrical limits. Operation near this limit requires careful attention to ambient temperature, PCB copper area, and derating curves - particularly since R_θJA = 200 °C/W implies a 20 °C rise per 100 mW dissipated. For reliable long-term use in amplification roles, design targets typically stay below −50 mA.

Does the 2N5087BU have a specified noise figure across multiple frequencies?

Yes, the 2N5087BU specifies noise figure (NF) at three operating points: 2.0 dB at I_C = −20 µA with R_S = 10 kΩ (10 Hz–15.7 kHz), 3.0 dB at I_C = −100 µA with R_S = 3 kΩ (1 kHz), and 2.0 dB again under identical low-current conditions. These values are measured per standard methods and confirm the 2N5087BU's suitability for ultra-low-noise front-end designs where input-referred noise must remain below 5 nV/√Hz.

Is the 2N5087BU pin-compatible with other TO-92 PNP transistors like the 2N3906?

No, the 2N5087BU is not pin-compatible with the 2N3906. While both use TO-92 packages, the 2N5087BU follows the Fairchild-standard pinout (Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector), whereas the 2N3906 uses the JEDEC-standard arrangement (Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base). Swapping them without board revision will result in circuit failure. Always verify pinout diagrams in the respective datasheets before substitution.

What is the typical V_CE(sat) for the 2N5087BU and how does it affect switching performance?

The 2N5087BU exhibits V_CE(sat) = −0.3 V at I_C = −10 mA and I_B = −1.0 mA. This low saturation voltage minimizes conduction loss in linear regulator pass elements and improves efficiency in low-duty-cycle PNP switch applications. However, because the device is optimized for amplification-not switching-the storage time and fall time are not characterized; for fast digital switching, dedicated switching transistors like the NSS12201LT1G are recommended instead of the 2N5087BU.

Can the 2N5087BU be used in surface-mount designs?

The 2N5087BU itself is only offered in the through-hole TO-92 package. For surface-mount implementation, the functionally identical MMBT5087 - which shares all electrical specifications including h_FE, V_CEO, NF, and f_T - is available in SOT-23. While the 2N5087BU cannot be directly mounted on SMT pads, its TO-92 footprint is widely supported in mixed-technology boards, and adapters exist for prototyping SMT-compatible layouts using the through-hole part.