onsemi BC546TAR

Overview

BC546TAR from ON Semiconductor is an NPN epitaxial silicon transistor designed for general-purpose switching and amplification in low-power analog and digital circuits. It features V_CEO = 65 V, I_C = 100 mA, P_C = 500 mW, h_FE range of 110–800 (depending on grade), and TO-92 package - commonly used in signal conditioning stages of consumer audio, power supply feedback loops, and discrete logic interface circuits.

For engineers reviewing the BC546TAR datasheet, pinout, applications, or equivalent options, key selection criteria include its 65 V collector-emitter breakdown voltage, low saturation voltage (V_CE(sat) ≤ 250 mV at I_C = 10 mA), DC current gain classification (Grade A/B/C), noise performance (2.0–10.0 dB NF), and TO-92 mechanical compatibility with legacy through-hole PCB layouts.

Technical Context

The BC546TAR operates as a standard bipolar junction transistor with fixed three-terminal topology (C-B-E), optimized for linear amplification and saturated switching. Its epitaxial base construction enables stable h_FE across temperature and supports reliable operation up to T_J = 150°C.

It exhibits f_T = 300 MHz at V_CE = 5 V and I_C = 10 mA, Cob = 3.5–6.0 pF, and V_BE(on) = 580–700 mV - confirming suitability for medium-frequency small-signal amplification and fast-switching applications below 10 MHz.

Key Specifications

Pinout & Package

BC546TAR is housed in a JEDEC-standard TO-92 plastic package with straight leads (bulk/ammo/tape-and-reel variants). The package provides mechanical robustness, low thermal resistance (R_θJA ≈ 200°C/W), and compatibility with wave soldering and manual prototyping.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC546TAR, BC547BTA trades 20 V breakdown margin for broader distribution and lower unit cost in low-voltage designs, while PN2222A offers higher current capacity at the expense of pin-compatible replacement and increased saturation loss.

Availability

BC546TAR is available at Aetrix Electronics and suitable for audio preamplification, power supply feedback control, and discrete logic interface applications requiring stable component supply, long-term obsolescence management, and full traceability from ON Semiconductor's authorized channel.

Supply support for BC546TAR 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 energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BC546TAR belongs to ON Semiconductor's legacy general-purpose transistor product line - originally developed by Fairchild - intended for cost-sensitive, high-volume applications demanding reliability, consistency, and broad design reuse across decades of electronics hardware.

FAQ

What is the absolute maximum collector-emitter voltage rating for BC546TAR?

The absolute maximum V_CEO for BC546TAR is 65 V at T_A = 25°C. This rating defines the upper limit before avalanche breakdown occurs. Operation above this voltage risks permanent damage. Derating is required above 25°C ambient per the datasheet's thermal curves. BC546TAR must not be used in circuits where transient spikes exceed 65 V without clamping protection.

Does BC546TAR have a specified noise figure, and under what conditions is it measured?

Yes, BC546TAR has a noise figure of 2.0–10.0 dB, measured at V_CE = 5 V, I_C = 200 μA, f = 1 kHz, and R_G = 2 kΩ. This specification applies to the BC546/BC547/BC548 variants. The value varies with grade and operating point; lower values occur in higher-h_FE grades and optimized bias conditions. BC546TAR's noise performance makes it suitable for low-level analog signal amplification.

What is the pin configuration of BC546TAR when viewed from the flat side with leads pointing downward?

When viewing BC546TAR from the flat side with leads pointing downward, the pin order from left to right is: 1 – Collector, 2 – Base, 3 – Emitter. This TO-92 pinout is standardized across all BC546-series variants and matches JEDEC TO-92 specifications. Incorrect orientation during PCB layout or assembly will result in circuit malfunction or device damage.

How does the h_FE classification (A/B/C) affect BC546TAR's performance in switching applications?

The h_FE grade (A: 110–220, B: 200–450, C: 420–800) directly determines required base drive current to achieve saturation. For example, at I_C = 10 mA, Grade C needs ~25 μA base current, while Grade A may require >90 μA. Using mismatched grades without adjusting base resistors can cause incomplete turn-on or excessive power dissipation. BC546TAR's grading enables predictable design across production lots.

Is BC546TAR RoHS compliant and halogen-free?

Yes, BC546TAR is RoHS compliant and halogen-free per ON Semiconductor's product change notices and material declarations. It meets EU Directive 2011/65/EU and IEC 61249-2-21:2013 standards. Full compliance documentation, including substance declarations and test reports, is available via ON Semiconductor's Quality & Environmental portal using the BC546TAR part number.