onsemi BC337G

Overview

BC337G from onsemi is an NPN general-purpose bipolar junction transistor (BJT) in TO-92 package, rated for 45 V V_CEO, 800 mA I_C, and 625 mW P_D, commonly used as a low-voltage switch or small-signal amplifier in power management and interface circuits.

For engineers reviewing the BC337G datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain (h_FE = 100–630 at I_C = 10 mA), saturation voltage (V_CE(sat) ≤ 0.5 V @ I_C/I_B = 100 mA/5 mA), thermal resistance (R_θJA = 200 °C/W), and TO-92 mechanical compatibility.

Technical Context

The BC337G operates as a silicon-based NPN BJT with epitaxial planar construction, optimized for linear amplification and saturated switching in DC-coupled and pulse applications. Its base-emitter junction is rated for ±5 V reverse bias, and collector-base breakdown voltage is specified at 50 V (V_CB0).

It supports continuous collector current up to 800 mA with guaranteed h_FE range across three gain groups (G: 100–250, H: 160–400, K: 250–630), and exhibits typical transition frequency f_T of 100 MHz at I_C = 10 mA, V_CE = 5 V.

Key Specifications

Pinout & Package

BC337G is housed in a standard TO-92 plastic package with 3-pin vertical lead configuration and JEDEC registered outline. Pin identification follows EIAJ SC-43 standard: emitter (E), base (B), collector (C) from left to right when viewing the flat side with leads downward.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC337-40 and BC547C, the BC337G offers balanced performance: higher current capability than BC547C and broader h_FE tolerance than BC337-40, making it optimal for cost-sensitive industrial control and consumer interface designs requiring 100–500 mA operation.

Availability

BC337G is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller interface stages, relay drivers, and linear regulator pass elements requiring stable component supply and long-term industrial availability.

Supply support for BC337G 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

onsemi is a global semiconductor supplier delivering energy-efficient power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The BC337G belongs to onsemi's General Purpose Transistor product line, designed for reliable, cost-effective switching and amplification in high-volume consumer, industrial, and computing systems.

FAQ

What is the maximum collector-emitter voltage rating for BC337G?

The BC337G has a maximum collector-emitter voltage (V_CEO) rating of 45 V. This value is measured under open-base conditions and defines the upper limit of voltage the transistor can block between collector and emitter without breakdown. Exceeding this rating risks permanent device failure. The BC337G datasheet confirms this specification at T_A = 25 °C with derating applied above that temperature.

Does BC337G have a built-in base-emitter resistor?

No, the BC337G does not include an integrated base-emitter resistor. It is a bare NPN transistor requiring external base biasing components. Unlike digital transistors (e.g., MMBT3904L), the BC337G relies on discrete resistors for current limiting and turn-off assurance. This gives designers full control over base drive characteristics but mandates careful calculation of R_B to ensure saturation across temperature and process variation.

What is the thermal resistance (R_θJA) of BC337G in TO-92 package?

The BC337G has a junction-to-ambient thermal resistance (R_θJA) of 200 °C/W when mounted on a standard FR-4 PCB with minimal copper area. This value assumes natural convection cooling and defines how much the junction temperature rises above ambient per watt of dissipated power. For reliable operation at full 625 mW rating, ambient temperature must remain below 25 °C; otherwise, derating is required per the datasheet curve.

How does BC337G differ from BC337-25?

The BC337G and BC337-25 share identical electrical specifications and TO-92 packaging, but differ in h_FE bin designation: BC337G corresponds to the "G" gain group (h_FE = 100–250), while BC337-25 specifies minimum h_FE = 250. The "G" suffix indicates compliance with onsemi's standardized gain sorting, whereas "-25" reflects an older part-numbering convention. Both are functionally interchangeable where gain tolerance permits.

Can BC337G be used in audio amplifier stages?

Yes, the BC337G can be used in low-power audio amplifier stages such as preamplifiers or driver stages, thanks to its 100 MHz f_T and linear h_FE behavior. However, its noise figure and distortion characteristics are not optimized for high-fidelity applications. For best results, operate within its specified I_C range (1–100 mA) and avoid clipping by limiting V_CE swing to ≤15 V. The BC337G datasheet includes small-signal AC parameters supporting audio-band design validation.