onsemi BD239C

Overview

BD239C from onsemi is a PNP epitaxial silicon power transistor in TO-220-3LD package, rated for 100 V V_CEO(SUS), 2 A DC collector current, and 30 W collector dissipation at T_C = 25 °C; used in medium-power linear regulators and switching circuits such as DC motor drivers and relay drivers.

For engineers reviewing the BD239C datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO(SUS) = 100 V, h_FE ≥ 40 at I_C = 0.2 A, V_CE(sat) ≤ 0.7 V at I_C = 1 A/I_B = 0.2 A, thermal performance in TO-220, and complementary pairing with BD240C.

Technical Context

The BD239C operates as a medium-power PNP bipolar junction transistor optimized for linear amplification and hard-switching duty. Its sustaining voltage rating (V_CEO(SUS) = 100 V) and pulse-rated I_CP = 4 A support robust operation under transient overloads in industrial control circuits.

Designed with epitaxial base construction, it delivers h_FE = 40–100 (min–max range per test condition), V_BE(on) ≤ 1.3 V at I_C = 1 A, and low saturation voltage-enabling efficient current sourcing in emitter-follower and high-side switch configurations.

Key Specifications

Pinout & Package

BD239C is housed in a TO-220-3LD (Case 340AT) package with integral metal tab for heatsinking. The plastic body provides electrical isolation between collector and mounting surface when insulated hardware is used.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BD239C, MJD239G trades TO-220 mechanical robustness and thermal capacity for SMT compatibility, while BD239 reduces voltage safety margin without functional or pinout change-making BD239C the optimal choice for 48 V industrial switching where 100 V blocking and 30 W dissipation are required.

Availability

BD239C is available at Aetrix Electronics and suitable for DC motor control, linear voltage regulation, and relay driver applications requiring stable component supply, long-lifecycle support, and traceable sourcing from onsemi's discontinued-but-supported product line.

Supply support for BD239C 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 supplier focused on energy-efficient electronics for automotive, industrial, cloud, and IoT applications.

The BD239C belongs to onsemi's legacy discrete power transistor family, engineered for medium-power linear and switching functions in industrial control, power supplies, and electromechanical interface circuits.

FAQ

What is the maximum continuous collector current rating for BD239C?

The BD239C has a maximum continuous collector current (I_C) rating of 2 A at T_C = 25 °C. This value decreases with rising case temperature-derating is required above 25 °C per the datasheet's thermal resistance curve. For reliable operation at ambient temperatures above 50 °C, a heatsink must be used to maintain T_C ≤ 25 °C or apply appropriate linear derating. The BD239C also supports 4 A pulsed current under strict duty cycle and pulse width limits.

Is BD239C pin-compatible with BD239 or BD239B?

Yes, BD239C shares identical TO-220-3LD pinout (Base–Collector–Emitter) and mechanical footprint with BD239 and BD239B. However, BD239C offers higher V_CEO(SUS) = 100 V versus 80 V for BD239 and 90 V for BD239B. Electrical differences affect voltage-margin-critical designs, but PCB layout and mounting remain unchanged across this series.

Does BD239C require a heatsink in typical 1 A switching applications?

Yes, BD239C typically requires a heatsink in 1 A switching applications. At I_C = 1 A and V_CE(sat) ≈ 0.7 V, conduction loss is ~0.7 W-but switching losses and ambient temperature elevate junction temperature. With R_θJC = 1.7 °C/W and R_θCA > 40 °C/W for bare device, even modest power dissipation exceeds safe T_J = 150 °C without thermal management. A small clip-on heatsink reduces R_θCA to ~20 °C/W, enabling reliable 1 A operation.

What is the minimum h_FE guaranteed for BD239C at 1 A collector current?

The BD239C guarantees h_FE ≥ 15 at I_C = 1 A, V_CE = 4 V, and T_C = 25 °C. This lower gain at high current reflects device physics and must be accounted for in base drive design-e.g., a 1 A load requires ≥67 mA base current to ensure saturation. Designers should verify actual h_FE across temperature and aging in final application, as typical values may reach 60–80 under same conditions.

Can BD239C be used as a direct replacement for BD240C in a circuit?

No, BD239C cannot replace BD240C directly because they are complementary types: BD239C is PNP and BD240C is NPN. Swapping them would invert logic polarity and reverse current flow direction. They are intended for paired use-for example, BD239C as high-side switch and BD240C as low-side switch in H-bridge or push-pull stages. Substitution requires full circuit reanalysis and likely layout changes.