onsemi BD244A

Overview

BD244A from ON Semiconductor is a PNP epitaxial silicon power transistor in TO-220 package, rated for −60 V V_CEO, −6 A continuous collector current, 65 W power dissipation at T_C = 25°C, with DC current gain (h_FE) ≥30 at I_C = −0.3 A and V_CE = −4 V. It serves as a medium-power linear amplifier or switching device in DC motor drives and power supply output stages.

For engineers reviewing the BD244A datasheet, pinout, applications, or equivalent options, key selection criteria include its −60 V V_CEO rating, TO-220 thermal performance, complementary pairing with BD243A, and verified safe operating area up to 10 ms pulse width under specified bias conditions.

Technical Context

The BD244A operates as a PNP bipolar junction transistor with fixed emitter-base and collector-base junction structures optimized for linear and switching operation in medium-power circuits. Its design supports stable DC biasing with h_FE ≥30 at low current and ≥15 at I_C = −3 A, and features V_CE(sat) ≤ −1.5 V at I_C = −6 A / I_B = −1 A.

Thermal management is enabled by its TO-220 package with case-to-ambient thermal resistance dependent on heatsink mounting; maximum junction temperature is 150°C, and storage range spans −65°C to +150°C. The device is not rated for life support or implantable medical use per ON Semiconductor's policy.

Key Specifications

Pinout & Package

BD244A uses the standard TO-220 package with three leads: lead 1 (Base), lead 2 (Collector), lead 3 (Emitter), mounted on a metal tab thermally connected to the collector.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD244 and BD244C, the BD244A offers optimal balance of through-hole manufacturability, 65 W thermal capacity, and −60 V rating for 24–36 V industrial power stages-making it preferred where board-level serviceability and heatsink flexibility outweigh SMT density or ultra-high-voltage margin needs.

Availability

BD244A is available at Aetrix Electronics and suitable for DC motor control, linear power supply regulation, audio amplifier output stages, and industrial relay driver applications requiring stable component supply and long-term industrial lifecycle support.

Supply support for BD244A 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

ON Semiconductor is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete devices for automotive, industrial, and cloud power applications.

The BD244A belongs to ON Semiconductor's legacy Fairchild discrete transistor portfolio, engineered for medium-power linear and switching applications where reliability, thermal robustness, and complementary NPN/PNP pairing are essential.

FAQ

What is the maximum collector-emitter voltage rating for BD244A?

The BD244A has a maximum collector-emitter voltage (V_CEO) rating of −60 V at T_C = 25°C. This rating applies under open-base conditions and defines the upper limit for safe DC or pulsed operation without avalanche breakdown. Exceeding this voltage-even briefly-may cause irreversible damage. Derating is required above 25°C case temperature per the published power derating curve in the BD244A datasheet.

Is BD244A pin-compatible with BD244, BD244B, and BD244C?

Yes, BD244A shares identical TO-220 package dimensions, pinout (Base–Collector–Emitter), and mechanical mounting with BD244, BD244B, and BD244C. All variants use lead 1 for Base, lead 2 for Collector, and lead 3 for Emitter. However, their absolute maximum ratings differ: BD244A is rated for −60 V V_CEO, whereas BD244 is −45 V, BD244B is −80 V, and BD244C is −100 V-so electrical substitution requires verification against circuit voltage stress.

What is the typical DC current gain (h_FE) of BD244A at different operating points?

The BD244A exhibits h_FE ≥30 (minimum) at V_CE = −4 V and I_C = −0.3 A, and h_FE ≥15 (minimum) at V_CE = −4 V and I_C = −3 A. These values are guaranteed across temperature and process variation. Typical h_FE may reach 75–100 at low current, but design must rely on minimums. The BD244A datasheet provides h_FE vs. I_C curves confirming gain roll-off above 1 A, critical for base drive sizing in switching applications.

Can BD244A be used in parallel configurations for higher current handling?

BD244A is not recommended for direct paralleling without individual emitter resistors or active current balancing due to h_FE and V_BE parameter spread across units. Even with matched devices, thermal coupling differences can cause current hogging. If higher current is needed, consider a single higher-rated device like BD244C or evaluate MOSFET alternatives with inherent current-sharing characteristics. Always validate thermal distribution with infrared imaging in prototype builds.

Does BD244A require a heatsink in standard operation?

Yes, BD244A requires a heatsink for any sustained operation above ~1.5 A collector current or when dissipating more than ~5 W continuously. Its 65 W P_C rating assumes T_C = 25°C-achievable only with substantial heatsinking and forced airflow. Without a heatsink, power dissipation is limited to <1 W at room ambient. Thermal calculations must include junction-to-case (R_θJC) and case-to-ambient (R_θCA) resistances, both documented in the BD244A datasheet.