onsemi BC849CMTF

Overview

BC849CMTF 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 = 420–800 (Class C), low noise (1.4 dB NF at 30–15 kHz), and f_T = 300 MHz - used in audio preamplifier stages and signal switching in portable instrumentation.

For engineers reviewing the BC849CMTF datasheet, pinout, applications, or equivalent options, key selection criteria include verified h_FE classification, low-noise performance at microamp bias, SOT-23 thermal derating behavior, and compatibility with automated pick-and-place in high-density PCB assembly.

Technical Context

This device operates as a general-purpose NPN bipolar junction transistor optimized for linear amplification and fast switching in low-power analog and digital circuits. Its epitaxial base structure enables stable h_FE across temperature and consistent V_BE(on) (580–720 mV) at I_C = 2–10 mA.

The BC849CMTF belongs to the BC846–BC850 family with fixed pinout (1=Base, 2=Emitter, 3=Collector) and shares absolute maximum ratings with BC848/BC849 variants, but distinguishes itself via Class C h_FE binning and lower noise figure versus BC846/BC847.

Key Specifications

Pinout & Package

SOT-23 plastic surface-mount package with gull-wing leads, 1.3 mm height, 2.9 mm × 1.3 mm footprint, and JEDEC MO-178 compliant dimensions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC849BMTF and MMBT3904LT1G, the BC849CMTF delivers superior gain consistency and lower noise in microamp-biased linear stages, making it preferred for precision analog signal conditioning where h_FE spread and SNR directly impact system accuracy.

Availability

BC849CMTF is available at Aetrix Electronics and suitable for audio preamplifiers, RF intermediate frequency amplifiers, low-power signal switching, and current mirror reference circuits requiring stable component supply and traceable SOT-23 sourcing.

Supply support for BC849CMTF 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 BC849CMTF belongs to Fairchild's BC846–BC850 family of general-purpose NPN transistors designed for high-volume, cost-sensitive applications in consumer electronics, industrial controls, and portable instrumentation where reliability, consistency, and manufacturability are critical.

FAQ

What is the guaranteed h_FE range for BC849CMTF?

The BC849CMTF is binned to Class C, guaranteeing a DC current gain (h_FE) of 420 to 800 when measured at V_CE = 5 V and I_C = 2 mA. This tight h_FE range ensures predictable gain in production amplifier circuits and reduces calibration overhead in analog signal chains using the BC849CMTF.

Does BC849CMTF support low-noise audio applications?

Yes, the BC849CMTF has a specified noise figure of 1.4 dB at V_CE = 5 V, I_C = 200 μA, and f = 30–15 kHz, making it suitable for low-level audio preamplification. Its low-noise performance is confirmed in the original Fairchild BC846–BC850 datasheet Rev. B1 and directly applies to the BC849CMTF variant.

What is the maximum power dissipation for BC849CMTF at 70°C ambient?

At T_A = 70°C, the BC849CMTF's maximum power dissipation is derated to approximately 217 mW, calculated using its 310 mW rating at 25°C and thermal resistance θ_JA ≈ 400°C/W. This derating must be applied in thermally constrained PCB layouts to avoid exceeding the 150°C junction limit.

Is BC849CMTF pin-compatible with other transistors in the BC846–BC850 series?

Yes, all BC846–BC850 variants including BC849CMTF use identical SOT-23 pinout: Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector. This uniformity allows direct substitution within the family for gain or noise optimization without layout changes - provided voltage and current ratings remain within spec for the BC849CMTF.

What does the "TF" suffix indicate in BC849CMTF?

The "TF" suffix in BC849CMTF denotes tape-and-reel packaging - specifically, 3000 units per reel in embossed carrier tape conforming to EIA-481 standards. This format enables automated surface-mount assembly and is standard across Fairchild's SOT-23 transistor offerings including the BC849CMTF.