onsemi BC547

Overview

BC547CTFR from ON Semiconductor is an NPN epitaxial silicon transistor in TO-92 package, rated for V_CEO = 45 V, I_C = 100 mA, and P_C = 500 mW, with h_FE = 420–800 (Class C), used in general-purpose switching and low-noise amplification circuits including audio preamps and sensor signal conditioning.

For engineers reviewing the BC547CTFR datasheet, pinout, applications, or equivalent options, this part serves as a cost-effective, through-hole discrete solution where moderate voltage handling, DC gain stability, and thermal reliability up to 150°C junction temperature are required in industrial control and consumer electronics designs.

Technical Context

The BC547CTFR operates as a standard bipolar junction transistor with fixed emitter-base and collector-base junctions, supporting linear amplification and saturated switching modes. Its h_FE classification (C-grade) ensures minimum DC current gain of 420 at I_C = 2 mA and V_CE = 5 V, while f_T = 300 MHz enables RF-capable small-signal operation up to VHF band.

Designed for DC-coupled and AC-coupled configurations, it features V_BE(on) = 580–700 mV and V_CE(sat) = 90–250 mV at I_C = 10 mA / I_B = 0.5 mA, enabling predictable biasing in emitter-follower and common-emitter topologies without external compensation.

Key Specifications

Pinout & Package

BC547CTFR uses the industry-standard TO-92 3-lead plastic package with straight leads (JEDEC TO-92 compliant), optimized for manual soldering and wave soldering in through-hole PCB assembly. Dimensions conform to Figure 7 and Figure 8 in the original Fairchild datasheet Rev. 1.1.1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC547BTA and 2N3904, BC547CTFR delivers higher guaranteed h_FE, tighter noise performance, and tape-and-reel packaging for automated manufacturing - making it optimal for new designs requiring consistent gain, low-noise analog stages, and SMT line integration.

Availability

BC547CTFR is available at Aetrix Electronics and suitable for audio pre-amplifiers, sensor signal conditioning, LED drivers, and relay interface circuits requiring stable component supply across production volumes and long-term industrial deployments.

Supply support for BC547CTFR 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 is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete solutions for automotive, industrial, and consumer markets.

The BC547CTFR belongs to ON Semiconductor's legacy general-purpose transistor product line, originally developed by Fairchild Semiconductor to deliver reliable, low-cost NPN switching and amplification in through-hole and automated assembly environments.

FAQ

What is the pin configuration of BC547CTFR?

The BC547CTFR uses the standard TO-92 pinout: Pin 1 is Collector, Pin 2 is Base, and Pin 3 is Emitter when viewing the flat side of the package with leads pointing downward and left-to-right orientation. This configuration is confirmed in the Fairchild BC546–BC550 datasheet Rev. 1.1.1, Figure 7 and Figure 8, and remains unchanged under ON Semiconductor's product continuity program.

Is BC547CTFR RoHS compliant?

Yes, BC547CTFR is RoHS compliant and lead-free per ON Semiconductor's product compliance documentation. The device meets EU Directive 2011/65/EU and subsequent amendments, with homogeneous material analysis confirming Pb content below 0.1 wt% and full compliance with all restricted substances listed in the directive.

What is the maximum operating temperature for BC547CTFR?

The BC547CTFR has a maximum junction temperature (T_J) of 150°C and a storage temperature range of –65°C to +150°C. Derating is required above 25°C ambient: power dissipation must be reduced linearly to zero at 150°C case temperature, per the absolute maximum ratings table in the official datasheet.

Can BC547CTFR replace BC547B in existing designs?

BC547CTFR can replace BC547B in most cases, but designers must verify h_FE requirements: BC547B has h_FE = 200–450, while BC547CTFR (Class C) guarantees 420–800. If the circuit relies on lower gain for stability or bias margin, revalidation of DC operating points is recommended before substitution.

Does BC547CTFR have a documented complementary PNP transistor?

Yes, BC547CTFR is explicitly documented as complementary to BC557 and BC558 PNP transistors in the Fairchild BC546–BC550 datasheet Rev. 1.1.1. These pairs share matched V_CEO, I_C, and thermal characteristics, enabling balanced push-pull output stages and differential amplifier designs without gain mismatch.