onsemi BC184L_D27Z

Overview

BC184L_D27Z from Fairchild Semiconductor is a silicon NPN small-signal transistor in TO-92 package, rated for 30 V V_CEO, 500 mA I_C, and 350 mW P_C at T_a = 25°C, with h_FE ≥ 130 at V_CE = 5 V and I_C = 100 mA - used in low-power amplification and switching circuits in consumer audio preamps and signal conditioning stages.

For engineers reviewing the BC184L_D27Z datasheet, pinout, applications, or equivalent options, key selection considerations include its 150 MHz f_T, 5 pF C_OB, 4 dB noise figure at 1 kHz, V_BE(sat) = 1.2 V at I_C = 100 mA/I_B = 5 mA, and TO-92 mechanical compatibility with legacy through-hole designs.

Technical Context

The BC184L_D27Z operates as a general-purpose NPN bipolar junction transistor optimized for linear amplification and low-speed switching. Its h_FE spans 100–900 depending on bias (10 µA to 100 mA), and it delivers 4 dB noise figure at 200 mA collector current with 2 kΩ source resistance - confirming suitability for low-noise analog front-ends.

Thermal design is constrained by a 150°C maximum junction temperature and 350 mW power dissipation at ambient 25°C, with derating required above 25°C per the specified thermal resistance curve. The device exhibits V_CE(sat) = 0.25 V at I_C = 100 mA/I_B = 5 mA, enabling efficient saturation in driver-stage applications.

Key Specifications

Pinout & Package

BC184L_D27Z is housed in a standard TO-92 plastic package with 3 leads, lead spacing 1.27 mm, body height ≤ 3.86 mm, and overall length 4.58 mm. Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base - verified per Fairchild Rev. A1 mechanical drawing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN small-signal transistor applications.

Compared with BC184L_D27Z, BC547B offers higher breakdown voltage and bandwidth at modest noise trade-off, while 2N3904 provides greater RF capability but reduced drive strength - selection depends on whether voltage margin, current delivery, or frequency response dominates the design requirement.

Availability

BC184L_D27Z is available at Aetrix Electronics and suitable for audio pre-amplifier stages, low-power relay drivers, signal level shifting, and discrete oscillator cores requiring stable component supply across industrial, consumer, and prototyping environments.

Supply support for BC184L_D27Z 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 manufacturer specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The BC184L_D27Z belongs to Fairchild's legacy silicon NPN small-signal transistor family, designed for cost-sensitive, high-reliability linear and switching applications in consumer electronics and industrial controls.

FAQ

What is the maximum collector current rating for BC184L_D27Z?

The BC184L_D27Z has a maximum DC collector current rating of 500 mA, as specified in the Absolute Maximum Ratings table under I_C. This rating applies at T_C = 25°C with appropriate PCB copper area for heat dissipation. Derating is required above ambient 25°C per the thermal resistance curve in the datasheet, and pulsed operation must be evaluated separately with duty cycle and peak current constraints.

Does BC184L_D27Z have a documented noise figure specification?

Yes, BC184L_D27Z specifies a noise figure of 4 dB at V_CE = 5 V, I_C = 200 mA, R_G = 2 kΩ, and f = 1 kHz. This value is measured under standardized conditions and confirms its suitability for low-noise analog amplification tasks such as microphone preamplifiers, where preserving signal integrity at low input levels is critical.

What is the pin configuration of BC184L_D27Z in TO-92 package?

The BC184L_D27Z uses the standard TO-92 pinout: Pin 1 is Emitter, Pin 2 is Collector, and Pin 3 is Base - confirmed in the "Package Dimensions" section of the Fairchild datasheet Rev. A1. This orientation is viewed with the flat side facing the user and leads pointing downward; correct identification is essential to avoid reverse-bias damage during circuit assembly.

Can BC184L_D27Z be used in switching applications?

Yes, BC184L_D27Z is suitable for low-speed switching applications, with V_CE(sat) = 0.25 V at I_C = 100 mA and I_B = 5 mA, and a maximum I_C of 500 mA. It supports reliable saturation in relay drivers and LED switches, though its f_T of 150 MHz limits use to frequencies below ~10 MHz for clean edge transitions without excessive storage time.

What is the junction temperature limit for BC184L_D27Z?

The BC184L_D27Z has a maximum junction temperature (T_J) of 150°C, as defined in the Absolute Maximum Ratings table. Operation beyond this limit risks permanent degradation of the silicon die. Thermal design must account for ambient temperature, PCB copper area, and power dissipation - with P_C = 350 mW at T_a = 25°C and linear derating above that point.