onsemi BC850BMTF

Overview

BC850BMTF from Fairchild Semiconductor is an NPN epitaxial silicon transistor in SOT-23 package, rated for 30 V V_CEO, 100 mA I_C, and 310 mW P_C, with h_FE = 200–450 (Class B), 1.2 dB noise figure at 1 kHz, and 300 MHz f_T. It serves as a low-noise amplifier or general-purpose switch in signal conditioning stages of portable audio and sensor interface circuits.

For engineers reviewing the BC850BMTF datasheet, pinout, applications, or equivalent options, key selection criteria include its Class B h_FE range, low V_CE(sat) (250 mV @ 100 mA/5 mA), SOT-23 footprint compatibility, and verified noise performance in sub-1 mA bias conditions.

Technical Context

The BC850BMTF operates as a discrete NPN bipolar junction transistor optimized for linear amplification and switching in low-power analog and digital signal paths. Its design emphasizes low noise (1.2 dB NF @ 1 kHz, 200 µA I_C) and stable DC current gain across its specified h_FE bin (200–450), with guaranteed V_BE(on) ≤ 720 mV at I_C = 10 mA.

It shares the BC846–BC850 family's absolute maximum ratings-including 30 V V_CEO, 30 V V_CBO, and 150 °C T_J-and uses the same SOT-23 package with standardized 1-Base / 2-Emitter / 3-Collector pinout. Its Cob = 3.5–6 pF and f_T = 300 MHz support RF-coupled preamplifier use up to ~100 MHz.

Key Specifications

Pinout & Package

SOT-23 plastic surface-mount package with gull-wing leads, 1.3 mm × 2.9 mm footprint, 1.1 mm height, and JEDEC MO-178 compliant dimensions. Thermal resistance R_θJA ≈ 320 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC849BMTF and MMBT3904LT1G, BC850BMTF delivers the lowest verified 1 kHz noise figure (1.2 dB) within its h_FE bin, making it the preferred choice for battery-powered audio and precision analog front-ends where SNR at sub-1 mA bias is critical.

Availability

BC850BMTF is available at Aetrix Electronics and suitable for portable audio preamps, industrial sensor interfaces, and LED driver switches requiring stable component supply, consistent h_FE binning, and low-noise performance in SOT-23 form factor.

Supply support for BC850BMTF 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 BC846–BC850 series was designed for cost-sensitive, high-volume consumer and industrial applications requiring reliable low-noise NPN transistors in ultra-small SOT-23 packages.

FAQ

What is the h_FE range for BC850BMTF?

The BC850BMTF is binned to Class B, with a guaranteed DC current gain (h_FE) range of 200 to 450 when measured at V_CE = 5 V and I_C = 2 mA. This binning ensures predictable bias point stability across production lots, reducing the need for gain-trimming resistors in amplifier designs using BC850BMTF.

Does BC850BMTF support low-noise audio applications?

Yes, BC850BMTF is specified with a noise figure of 1.2 dB at 1 kHz, 200 µA I_C, and R_G = 2 kΩ, making it suitable for electret microphone preamplifiers and other low-level analog signal conditioning tasks. Its low-noise performance is validated per the BC846–BC850 family datasheet Rev. B1, confirming BC850BMTF's suitability for audio front-ends where SNR is critical.

What is the maximum collector-emitter voltage rating for BC850BMTF?

The BC850BMTF has a maximum collector-emitter voltage (V_CEO) rating of 30 V, as defined in the absolute maximum ratings table of the official datasheet. This rating applies under DC conditions at T_A = 25°C and must be derated linearly above 25°C ambient temperature per the device's thermal characteristics.

Is BC850BMTF pin-compatible with other transistors in the BC846–BC850 family?

Yes, BC850BMTF uses the standard SOT-23 package with identical 1-Base / 2-Emitter / 3-Collector pinout shared across all BC846–BC850 variants, including BC847BMTF and BC849BMTF. This allows direct substitution within the same family when voltage, current, and noise requirements align, though h_FE bin and noise specs differ between part numbers.

What is the typical V_CE(sat) for BC850BMTF under switching conditions?

The BC850BMTF exhibits a typical collector-emitter saturation voltage (V_CE(sat)) of 250 mV when operated at I_C = 100 mA and I_B = 5 mA, as specified in the electrical characteristics table. This low saturation voltage minimizes power loss and improves efficiency in high-duty-cycle switching applications such as LED drivers and logic-level translation circuits using BC850BMTF.