onsemi BD240A

Overview

BD240A from ON Semiconductor is a PNP epitaxial silicon power transistor in TO-220 package, rated for -60 V V_CEO, -70 V V_CER, -2 A DC collector current, 30 W power dissipation at T_C = 25°C, and 150°C maximum junction temperature. It serves as a medium-power linear amplifier or switching device in complementary pairs with BD239A.

For engineers reviewing the BD240A datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO/V_CER rating alignment, h_FE consistency at I_C = -1 A, V_CE(sat) under -1 A/-0.2 A drive, thermal derating behavior, and TO-220 mechanical compatibility in high-current bias circuits.

Technical Context

The BD240A operates as a discrete PNP bipolar junction transistor with fixed gain structure optimized for medium-power linear and switching applications. Its V_CEO(sus) = -60 V and V_CER = -70 V define safe operating voltage limits under open-base and reverse-biased base conditions respectively.

DC current gain h_FE is specified at 15 (min) when V_CE = -4 V and I_C = -1 A, and 40 (min) at I_C = -0.2 A - indicating gain compression at higher currents. V_CE(sat) ≤ -0.7 V at I_C = -1 A and I_B = -0.2 A confirms low-saturation capability for switching use.

Key Specifications

Pinout & Package

BD240A uses the standard TO-220 package with 3 leads: Pin 1 = Base, Pin 2 = Collector (tab), Pin 3 = Emitter. The metal tab is electrically connected to the collector and must be isolated from chassis unless circuit topology permits direct connection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD243G and BD241C, BD240A offers proven TO-220 through-hole reliability and precise -60 V voltage rating for cost-sensitive 24–48 V industrial controls, while avoiding SMT rework or over-spec'd voltage headroom.

Availability

BD240A is available at Aetrix Electronics and suitable for audio power amplifiers, linear voltage regulators, DC motor drivers, and relay interface circuits requiring stable component supply and long-lifecycle support.

Supply support for BD240A 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 logic solutions for automotive, industrial, cloud, and consumer markets.

The BD240A belongs to ON Semiconductor's legacy power bipolar transistor product line, designed for medium-power linear amplification and robust switching in industrial control, power supplies, and audio systems.

FAQ

What is the maximum collector-emitter voltage rating for BD240A?

The BD240A has a maximum collector-emitter voltage rating of -60 V (V_CEO) with base open, and -70 V (V_CER) with base-emitter shorted. These values define absolute limits for safe DC and pulsed operation; exceeding either risks permanent breakdown. Designers must ensure worst-case circuit transients remain within V_CER to avoid failure during inductive switching.

Does BD240A have a complementary NPN transistor?

Yes, BD240A is explicitly designed as the PNP complement to BD239A (NPN). Both share identical TO-220 packaging, pinout (1-Base, 2-Collector, 3-Emitter), and matched voltage/current ratings - enabling balanced push-pull amplifier stages, differential pairs, and H-bridge driver topologies without gain or thermal mismatch concerns.

What is the DC current gain (h_FE) of BD240A at full load?

The BD240A specifies a minimum DC current gain (h_FE) of 15 when V_CE = -4 V and I_C = -1 A. This value reflects gain under typical switching conditions and determines required base drive current - for example, -1 A collector current demands at least -67 mA base current to guarantee saturation. At lighter loads (I_C = -0.2 A), h_FE rises to ≥40.

Can BD240A be used in surface-mount designs?

No, BD240A is exclusively offered in the through-hole TO-220 package and lacks a surface-mount variant. For SMT implementation, consider alternatives like MJD243G (TO-263) or NSS20501CF8T1G (SOT-89), but note these differ in pinout, thermal performance, and gain characteristics. BD240A requires drilled PCB mounting and mechanical heatsinking.

What is the thermal resistance junction-to-case for BD240A?

The BD240A datasheet does not specify R_θJC directly, but its 30 W power dissipation rating at T_C = 25°C implies an effective R_θJC ≈ 0.83°C/W (calculated as (150°C − 25°C)/30 W). Actual thermal performance depends on heatsink interface quality, mounting pressure, and thermal compound; designers should validate junction temperature using thermocouple measurement or IR imaging under real operating conditions.