onsemi BC372

Overview

BC372 from ON Semiconductor is an NPN silicon high-voltage Darlington transistor in TO-92 package, rated for V_CEO = 100 V, I_C = 1.0 A, and P_D = 625 mW at T_A = 25°C. It delivers h_FE ≥ 8.0 (min) at I_C = 250 mA, V_CE = 5 V, with V_CE(sat) ≤ 1.1 V and f_T ≥ 100 MHz - used in relay drivers, power supply control, and industrial switching circuits.

For engineers reviewing the BC372 datasheet, pinout, applications, or equivalent options, key selection criteria include its 100 V V_CEO, Darlington gain structure, TO-92 thermal resistance (R_JA = 200 °C/W), low saturation voltage, and compatibility with legacy through-hole power interface designs.

Technical Context

The BC372 implements a monolithic NPN Darlington pair to achieve high current gain (h_FE up to 160) while maintaining high breakdown voltage. Its internal structure enables single-stage amplification of weak base drive signals into robust collector current output without external gain staging.

It operates across −55°C to +150°C junction temperature range, supports DC and pulsed switching up to 100 MHz bandwidth, and exhibits low leakage (I_CBO ≤ 100 nA at V_CB = 80 V), making it suitable for stable high-voltage linear and switching applications where thermal margin and voltage headroom are critical.

Key Specifications

Pinout & Package

BC372 is housed in TO-92 (Case 29-11, Style 1), a through-hole plastic package with 3 leads and standardized mechanical dimensions per ANSI Y14.5M. The package provides adequate thermal performance for low-to-medium power linear/switching use with PCB copper pour assistance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage Darlington transistor applications.

Compared with BC373 and MJD127, the BC372 uniquely balances 100 V rating, TO-92 mountability, and Darlington gain in a cost-sensitive through-hole solution - ideal for space-constrained industrial controls where voltage margin and legacy compatibility are primary constraints.

Availability

BC372 is available at Aetrix Electronics and suitable for industrial relay drivers, linear power supply pass elements, and DC motor control circuits requiring stable component supply and long-term obsolescence management.

Supply support for BC372 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 (now onsemi) is a global semiconductor supplier focused on energy-efficient electronics, with core expertise in power management, analog, sensing, and connectivity solutions.

The BC372 belongs to the BC37x family of general-purpose high-voltage Darlington transistors designed for industrial control, power conversion, and electromechanical interface applications requiring rugged, through-hole switching capability.

FAQ

What is the maximum collector-emitter voltage rating for BC372?

The BC372 has a guaranteed minimum V_CEO rating of 100 V under test conditions (I_C = 100 µA). This allows safe operation in 48 V and 72 V DC systems with adequate transient margin. Exceeding this voltage risks avalanche breakdown and permanent device damage. Always observe derating curves in the BC372 datasheet for elevated temperature operation.

Is BC372 a single transistor or a Darlington pair?

The BC372 is a monolithic NPN Darlington transistor - it integrates two cascaded NPN transistors on one die to deliver high DC current gain (h_FE ≥ 8.0 at I_C = 250 mA). This eliminates the need for external gain staging and simplifies base drive circuitry compared to standard bipolar transistors.

What is the pin configuration of BC372 in TO-92 package?

When viewed with flat side facing outward and leads pointing down, BC372 pinout is: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector. This matches JEDEC TO-92 standard orientation and is confirmed in the official BC372/D datasheet Figure "Marking Diagram" and "Package Dimensions" section.

Does BC372 have a Pb-free version?

Yes - the BC372G is the officially designated Pb-free variant of BC372, manufactured with lead-free terminations and compliant with RoHS Directive 2011/65/EU. It shares identical electrical specifications and TO-92 packaging, and is marked with "BC372G" on the package body.

What is the typical DC current gain (hFE) of BC372 at 250 mA collector current?

The BC372 specifies h_FE minimum of 8.0 and maximum of 160 at I_C = 250 mA, V_CE = 5.0 V, and T_A = 25°C. Typical h_FE falls between 40–100 in production units under these conditions, as shown in Figure 1 of the BC372/D datasheet.