onsemi 2N6043

Overview

2N6043 from onsemi is an NPN silicon Darlington power transistor in a TO-220 package, rated for 60 V_CEO(sus) (min), 8 A continuous collector current, and 75 W power dissipation at T_C = 25°C. It features high DC current gain (h_FE = 1000 min @ I_C = 4.0 A), low V_CE(sat) ≤ 2.0 V @ I_C = 4.0 A / I_B = 16 mA, and built-in base-emitter shunt resistors - designed for medium-power linear amplification and low-speed switching in industrial control and power supply circuits.

For engineers reviewing the 2N6043 datasheet, pinout, applications, or equivalent options, key selection criteria include its complementary PNP pairing with 2N6040, thermal resistance (R_θJC = 1.67°C/W), safe operating area (SOA) limits up to 150°C junction temperature, and Pb-free RoHS-compliant TO-220 packaging suitable for through-hole power stage designs requiring robust DC gain and sustained current handling.

Technical Context

The 2N6043 operates as a monolithic Darlington pair with integrated base-emitter shunt resistors, enabling simplified biasing and improved turn-off behavior versus single transistors. Its SOA is limited by second breakdown at high V_CE/I_C combinations and thermally at elevated case temperatures, with pulse derating governed by transient thermal impedance curves.

Electrical performance is specified across –65°C to +150°C junction range, with h_FE maintaining ≥1000 at I_C = 4.0 A and V_CE = 4.0 V, while C_ob = 200 pF @ V_CB = 10 V enables predictable high-frequency cutoff in amplifier stages.

Key Specifications

Pinout & Package

2N6043 uses the standard TO-220 package (Case 221A, Style 1) with three leads: Collector (tab), Base (center), Emitter (right). The metal tab is electrically connected to the collector and must be isolated from chassis ground unless intentionally tied to high-side potential.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BD679 and TIP122, the 2N6043 provides the highest continuous current (8 A) in the TO-220 Darlington family with confirmed 60 V_CEO(sus) and integrated shunt resistor - making it optimal for industrial motor drivers and high-current linear regulators where thermal margin and drive simplicity are critical.

Availability

2N6043 is available at Aetrix Electronics and suitable for industrial motor control, DC power supply regulation, and AC solid-state relay driver applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant through-hole power transistors.

Supply support for 2N6043 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, with leadership in power management, analog, sensors, and connectivity solutions.

The 2N6043 belongs to onsemi's legacy plastic medium-power complementary transistor family, engineered for general-purpose amplifier and low-speed switching applications where reliability, thermal robustness, and high DC gain are prioritized over RF or high-frequency switching performance.

FAQ

What is the maximum collector-emitter sustaining voltage for the 2N6043?

The 2N6043 has a minimum collector-emitter sustaining voltage V_CEO(sus) of 60 Vdc at I_C = 100 mAdc and I_B = 0. This rating reflects its ability to block voltage in the off state under specified test conditions and defines its upper limit for DC or pulsed switching applications. Exceeding this voltage risks avalanche breakdown and permanent device failure.

Does the 2N6043 have a built-in base-emitter shunt resistor?

Yes, the 2N6043 features monolithic construction with a built-in base-emitter shunt resistor. This internal resistor improves turn-off speed and prevents spurious turn-on due to leakage current or noise, eliminating the need for an external pull-down resistor in most switching applications - a key differentiator from basic NPN transistors like the 2N2222 or BC547.

What is the thermal resistance from junction to case for the 2N6043?

The 2N6043 has a thermal resistance R_θJC of 1.67°C/W. This value quantifies how effectively heat transfers from the silicon junction to the metal tab (collector) under steady-state conditions. When mounted to a heatsink with proper thermal interface material, this parameter directly determines junction temperature rise above case temperature for a given power dissipation.

Can the 2N6043 be used in linear regulator applications?

Yes, the 2N6043 is suitable for series pass transistor roles in linear regulators, particularly where output currents approach 5–8 A and dropout voltage must be minimized. Its V_CE(sat) ≤ 2.0 V at I_C = 4.0 A and h_FE ≥ 1000 reduce base drive requirements and conduction losses. Thermal design must account for R_θJC = 1.67°C/W and maximum T_J = 150°C to ensure stability under full-load conditions.

Is the 2N6043 RoHS-compliant and lead-free?

Yes, the 2N6043G variant is explicitly marked as Pb-free and RoHS-compliant per onsemi documentation. The "G" suffix denotes compliance with EU RoHS Directive 2011/65/EU and related global environmental standards. This applies to both the silicon die and the TO-220 plastic package, which meets UL 94 V-0 flammability rating at 0.125 inch thickness.