Diodes Incorporated BCX56TA

Overview

BCX56TA from Diodes Incorporated is an NPN medium-power transistor in SOT89 package, rated for 80V V_CEO, 1A continuous collector current, and <500mV V_CE(sat) at 0.5A. It features epitaxial planar die construction, 150MHz f_T, and is used in AF output stages and medium-power switching circuits.

For engineers reviewing the BCX56TA datasheet, BCX56TA pinout, BCX56TA application, or BCX56TA equivalent, key selection criteria include V_CEO rating, thermal resistance (R_θJC = 39°C/W), h_FE range (100–250 at I_C = 150mA), and SOT89 thermal pad mounting requirements.

Technical Context

This NPN bipolar junction transistor operates in linear amplification and saturated switching modes, with guaranteed h_FE ≥100 at I_C = 150mA and V_CE = 2V. Its 100V V_CBO and 80V V_CEO support robust voltage margin in 24–48V industrial control rails.

Thermal design relies on the exposed collector pad: R_θJL = 13°C/W to solder point and R_θJC = 39°C/W to case enable effective heat transfer to PCB copper. ESD ratings meet JEDEC HBM Class 3A (4000V) and CDM (1000V).

Key Specifications

Pinout & Package

Package: SOT89 - Surface-mount plastic package with exposed collector pad for thermal management; 3-pin configuration; 0.055g mass; UL 94V-0 molding compound.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD127G and ZTX653, BCX56TA uniquely balances SOT89 compactness, 80V ruggedness, and 150MHz bandwidth-making it optimal for space-constrained 48V industrial drivers and audio outputs where thermal performance and voltage headroom are critical.

Availability

BCX56TA is available at Aetrix Electronics and suitable for audio amplifier output stages, industrial relay drivers, DC-DC converter switches, and automotive interior lighting control requiring stable component supply and long-term manufacturability.

Supply support for BCX56TA 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection solutions.

BCX56TA belongs to Diodes' BCX54/55/56 NPN/PNP medium-power transistor family, designed specifically for robust, thermally efficient switching and amplification in industrial, automotive, and consumer power electronics.

FAQ

What is the maximum safe operating temperature for BCX56TA?

The BCX56TA has an operating junction temperature range of –55°C to +150°C. Its thermal resistance R_θJC is 39°C/W, so with a 25°C ambient and 1W dissipation, junction temperature reaches ~164°C-exceeding limit. Derating per Figure 2 shows max power drops to ~0.7W at 100°C ambient. Always use thermal pad and copper area per datasheet layout.

Is BCX56TA pin-compatible with BCX54TA or BCX55TA?

Yes-BCX54TA, BCX55TA, and BCX56TA share identical SOT89 package, pinout (E-B-C), and mechanical dimensions. They differ only in voltage ratings: BCX54TA (45V), BCX55TA (60V), BCX56TA (80V). Substitution is electrically safe if voltage margin requirements are met.

Does BCX56TA require a heatsink in typical applications?

No external heatsink is needed if mounted per recommended SOT89 pad layout (15mm × 15mm 1oz copper), where R_θJA = 125°C/W allows ~0.7W dissipation at 25°C ambient. For >0.5W continuous operation or elevated ambient temperatures, increasing copper area or using thermal vias is advised instead of discrete heatsinks.

Can BCX56TA be used in linear regulator pass transistor applications?

Yes-it supports linear operation with h_FE ≥100 up to I_C = 150mA and maintains stable V_BE(on) ≤1.0V. However, its 0.55W nominal power rating (Note 5) limits pass transistor use to low-dropout, low-current (<300mA) regulators unless enhanced thermal design is implemented.