onsemi 2SA1020

Overview

2SA1020 from onsemi is a PNP bipolar junction transistor in TO-92 package, rated for 50 V V_CEO, 2.0 A continuous collector current, and 1.5 W power dissipation at T_C = 25°C. It delivers h_FE ≥ 70 at I_C = 500 mA and supports high-current switching in DC-DC converters and relay drivers.

For engineers reviewing the 2SA1020 datasheet, pinout, applications, or equivalent options, key selection criteria include V_CE(sat) ≤ 0.5 V at I_C/I_B = 10, f_T = 100 MHz, thermal resistance R_JC = 83.3°C/W, and Pb-free TO-92 compliance per ordering code 2SA1020RLRAG.

Technical Context

This PNP transistor operates with negative voltage/current polarities per standard BJT convention. Its safe operating area (SOA) is defined by thermal limit, wire bond limit, and second breakdown-validated up to −2.0 A and −2.0 V at T_J = 25°C.

DC current gain h_FE varies from 40 to 240 across I_C = 500 mA–1.5 A, while V_BE(sat) ≤ 1.2 V ensures reliable base drive under high-current saturation. The device is characterized at T_C = 25°C and derates linearly above that temperature.

Key Specifications

Pinout & Package

2SA1020 is housed in a TO-92 (Case 29-10, Style 14) plastic package with standardized lead orientation and Pb-free finish per ordering code 2SA1020RLRAG.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2SA1020, 2SA1774 offers higher minimum h_FE for reduced base drive overhead, while MJD2955T4G trades TO-92 compactness for tenfold current capacity and industrial-grade thermal performance-neither is pin-compatible, and both require layout revision.

Availability

2SA1020 is available at Aetrix Electronics and suitable for power supply switching, relay driving, motor interface, and linear regulator applications requiring stable component supply and long-term obsolescence management.

Supply support for 2SA1020 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 2SA1020 belongs to onsemi's general-purpose bipolar transistor product line, designed for cost-sensitive, high-reliability discrete switching and amplification in industrial, automotive, and consumer power systems.

FAQ

What is the maximum collector-emitter voltage rating for the 2SA1020?

The 2SA1020 has a maximum collector-emitter breakdown voltage V(BR)_CEO of 50 Vdc at I_C = 10 mA and I_B = 0. This rating defines the upper limit of reverse-biased voltage the transistor can withstand in common-emitter configuration without avalanche conduction. Exceeding this voltage risks permanent damage, and design margins should be applied per application stress conditions.

Is the 2SA1020 available in a Pb-free package?

Yes, the 2SA1020RLRAG variant is explicitly specified as Pb-free in the official onsemi datasheet. It uses the same TO-92 package as the standard 2SA1020 but complies with RoHS Directive 2011/65/EU. The "G" suffix in the part number confirms Pb-free construction, and the device carries appropriate marking per onsemi's Pb-Free Packaging Standard.

What is the typical DC current gain (hFE) of the 2SA1020 at 1.5 A collector current?

At I_C = 1.5 A and V_CE = 2.0 V, the 2SA1020 exhibits h_FE ranging from 40 to 240 per the datasheet's Electrical Characteristics table. The minimum guaranteed value is 40, making it suitable for applications where base drive current must be sized for worst-case gain. Typical curves show median h_FE ≈ 100–140 under these conditions.

Can the 2SA1020 be used in linear regulator applications?

Yes, the 2SA1020 is suitable as a pass transistor in low-to-medium current linear regulators. Its 1.5 W power dissipation at T_C = 25°C, R_JC = 83.3°C/W, and V_CE(sat) ≤ 0.5 V support stable operation at up to ~1.2 A output current with proper thermal design. The device's f_T = 100 MHz also aids loop stability in feedback-controlled topologies.

What is the thermal resistance from junction to ambient (RJA) for the 2SA1020 in TO-92 package?

The thermal resistance from junction to ambient (R_JA) for the 2SA1020 in standard TO-92 mounting is 125°C/W, as specified in the Thermal Characteristics table. This value assumes free-air convection on a non-PCB-mounted device. When soldered to PCB copper, actual R_JA improves significantly depending on pad size and thermal vias-designers should validate using measured or simulated thermal data for their specific layout.