onsemi BDW24TU

Overview

BDW24TU from Fairchild Semiconductor is a PNP epitaxial silicon Darlington transistor in TO-220 package, rated for -45 V V_CEO, -6 A I_C, 50 W P_C at T_C=25°C, with h_FE ≥1000 at I_C = -1 A, used in high-current switching and audio output stages.

For engineers reviewing the BDW24TU datasheet, pinout, applications, or equivalent options, key selection criteria include collector-emitter sustaining voltage, DC current gain at high current, saturation voltage under specified base drive, safe operating area boundaries, and thermal derating behavior in power amplifier and hammer driver designs.

Technical Context

The BDW24TU is a monolithic PNP Darlington pair with integrated emitter-base shunt resistor (not explicitly stated but implied by typical Darlington architecture and complementary pairing with BDW23 series), optimized for linear and switching operation in medium-power applications. It features low V_CE(sat) (-2 V at I_C = -2 A, I_B = -8 mA) and high h_FE to reduce base drive requirements.

Its absolute maximum ratings are defined at T_C = 25°C with strict thermal limits: T_J ≤ 150°C and P_C derates linearly above 25°C case temperature. The device is electrically characterized using pulsed test conditions (PW = 300 µs, duty cycle = 1.5%) for transient parameters like V_CEO(sus) and h_FE.

Key Specifications

Pinout & Package

BDW24TU is housed in a standard TO-220 package with vertical mounting orientation, metal tab connected to collector, and three leads: Base (lead 1), Collector (lead 2), Emitter (lead 3). The package provides mechanical robustness and direct heatsink interface via the collector-connected tab.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP Darlington transistor applications.

Compared with MJD2955G and BDW24C, the BDW24TU offers optimal balance of through-hole compatibility, proven thermal performance in TO-220 heatsinks, and sufficient -45 V rating for 24–48 V industrial control rails-making it preferred for cost-sensitive, serviceable, and thermally constrained designs.

Availability

BDW24TU is available at Aetrix Electronics and suitable for audio power amplifiers, electromechanical hammer drivers, and DC motor speed control systems requiring stable component supply and long-term industrial availability.

Supply support for BDW24TU 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The BDW24TU belongs to Fairchild's legacy power bipolar transistor family designed specifically for medium-power linear and switching applications including audio output stages and industrial actuator drivers.

FAQ

What is the maximum continuous collector current rating for BDW24TU?

The BDW24TU has a maximum continuous collector current (I_C) rating of -6 A at T_C = 25°C. This rating assumes adequate heatsinking; actual usable current decreases with rising case temperature per the 0.4 W/°C derating curve shown in the datasheet. Operation beyond this limit risks thermal runaway or permanent damage. Always verify thermal design margins using the BDW24TU's published power derating graph and SOA curves.

Is BDW24TU pin-compatible with BDW24A, BDW24B, or BDW24C?

Yes, BDW24TU shares identical TO-220 package dimensions, pinout (Base–Collector–Emitter), and mechanical mounting with BDW24A/B/C. All variants differ only in V_CEO/V_CBO ratings (-45 V to -100 V); electrical characteristics such as h_FE, V_CE(sat), and P_C remain consistent across the family. BDW24TU may be substituted for BDW24A in circuits where -45 V rating suffices, but not vice versa without voltage margin verification.

Does BDW24TU include an integrated protection diode?

Yes, BDW24TU incorporates an internal forward-biased diode with V_F = -1.8 V at I_F = -2 A, confirmed in the Electrical Characteristics table. This diode is connected between emitter and base terminals and functions as a clamp during reverse-bias transients, improving reliability in inductive load switching. It does not replace external flyback diodes in high-energy solenoid applications but reduces base-emitter stress.

What is the typical DC current gain (h_FE) of BDW24TU at full load?

The BDW24TU exhibits h_FE ≥1000 at V_CE = -3 V and I_C = -1 A, dropping to ≥100 at I_C = -6 A. This wide gain range reflects Darlington behavior: high gain at light loads ensures low base drive, while reduced gain at full load improves stability and thermal predictability. Designers should use the minimum h_FE value (100) for worst-case base resistor sizing in saturated-switch applications.

Can BDW24TU be used in complementary symmetry amplifier designs?

Yes, BDW24TU is explicitly designed as the PNP complement to the NPN BDW23 series (BDW23, BDW23A, etc.), sharing matched thermal and electrical characteristics. Its symmetric V_CEO, I_C, and h_FE profiles enable balanced push-pull operation in Class AB audio amplifiers. Bias networks must account for the PNP polarity-emitter connects to positive rail, collector to load-ensuring correct quiescent current setting and crossover distortion minimization.