onsemi BD135TG

Overview

BD135TG from onsemi is a plastic medium-power silicon NPN transistor designed for audio amplifier and driver stages in complementary or quasi-complementary circuits, with V_CEO = 45 V, I_C = 1.5 A, P_D = 12.5 W at T_C = 25°C, h_FE ≥ 25 (at I_C = 0.005 A), and TO-225 package. It operates across –55°C to +150°C junction temperature range.

For engineers reviewing the BD135TG datasheet, pinout, applications, or equivalent options, key selection criteria include its 45 V V_CEO, 1.5 A continuous collector current, 12.5 W case-rated power dissipation, DC current gain profile across bias conditions, and TO-225 mechanical compatibility in linear audio output stages.

Technical Context

This device functions as a medium-power linear switching and amplification element in Class AB audio output stages, where its complementary pairing with BD136G enables push-pull operation. Its thermal resistance R_JC = 10°C/W supports heatsink-mounted operation, and V_CE(sat) ≤ 0.5 V at I_C = 0.5 A / I_B = 0.05 A ensures low conduction loss in saturated switching.

The BD135TG exhibits h_FE = 25–250 depending on collector current (25 at I_C = 5 mA; up to 250 at I_C = 150 mA), and maintains V_BE(on) ≤ 1.0 V at I_C = 0.5 A - enabling predictable base drive requirements in discrete amplifier designs.

Key Specifications

Pinout & Package

BD135TG is housed in a TO-225 package (Case 77-09, Style 1) with three leads and an electrically connected backside tab serving as collector terminal. The package is Pb-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BD135G and MJE13003, BD135TG offers identical electrical performance to BD135G in rail packaging optimized for production throughput, while differing fundamentally from MJE13003 in gain profile, saturation behavior, and intended application domain - making BD135TG the sole appropriate choice for complementary audio output stages.

Availability

BD135TG is available at Aetrix Electronics and suitable for audio power amplifiers, DC motor drivers, linear voltage regulators, and discrete signal amplifiers requiring stable component supply and TO-225 mechanical compatibility.

Supply support for BD135TG 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 (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BD135TG belongs to onsemi's legacy medium-power bipolar transistor family, engineered specifically for cost-sensitive, thermally robust linear amplification and driver applications in audio and industrial control systems.

FAQ

What is the maximum collector-emitter voltage rating for BD135TG?

The BD135TG has a maximum collector-emitter sustaining voltage (V_CEO) of 45 V under specified test conditions (I_C = 0.03 A, I_B = 0). This rating defines the absolute upper limit for voltage applied between collector and emitter with the base open, and must be respected to prevent avalanche breakdown. Exceeding this value risks permanent device failure, especially under transient conditions or elevated temperatures.

Is BD135TG pin-compatible with BD135G?

Yes, BD135TG is fully pin-compatible with BD135G - both use identical TO-225 (Case 77-09, Style 1) packaging with emitter on pin 1, collector on pins 2 and 4 (including tab), and base on pin 3. The only distinction is packaging format: BD135TG ships in 50-unit rails for automated insertion, while BD135G ships in 500-unit boxes. Electrical and thermal specifications are identical.

What is the typical DC current gain (h_FE) of BD135TG at different operating points?

The BD135TG exhibits h_FE = 25 (minimum) at I_C = 5 mA and V_CE = 2 V, rising to 40–250 across I_C = 150–500 mA under same V_CE. This wide gain spread means circuit designs must accommodate variation - e.g., emitter degeneration resistors or feedback networks - rather than relying on fixed h_FE for bias stability. The BD135TG datasheet confirms these values under pulse-test conditions (≤300 µs, ≤2% duty cycle).

Can BD135TG be used in surface-mount assemblies?

No, BD135TG is a through-hole device in TO-225 package and is not designed for surface-mount reflow. Its leads are intended for axial or radial insertion into plated-through holes, and the metal tab requires mechanical mounting to a heatsink. Attempting SMT reflow will damage the internal die bond wires and compromise thermal integrity. For SMT alternatives, consider DPAK or D2PAK NPN transistors with comparable ratings.

Does BD135TG require a heatsink in normal operation?

Yes - BD135TG must be mounted to an external heatsink when dissipating more than ~1.25 W continuously, as its R_JA = 100°C/W limits ambient-only operation. At full 12.5 W case-rated dissipation, even a modest 10°C/W heatsink is required to hold junction temperature below 150°C. The metal tab (pins 2/4) is electrically and thermally connected to the collector, enabling direct thermal coupling to the heatsink with proper insulation if needed.