onsemi PN2222

Overview

PN2222 from onsemi is a general-purpose NPN silicon bipolar junction transistor (BJT) rated for 30 V_CEO, 600 mA continuous collector current, and 625 mW power dissipation at T_A = 25°C. It serves as a low-voltage switching or linear amplification device in discrete analog and digital interface circuits, commonly used in relay drivers, LED controls, and signal buffering.

For engineers reviewing the PN2222 datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-92 package, DC current gain (h_FE) of 35–300 across operating conditions, saturation voltage (V_CE(sat)) up to 1.6 V at I_C = 500 mA, and thermal resistance of 200°C/W junction-to-ambient.

Technical Context

The PN2222 operates as a single NPN transistor with fixed emitter-base-collector terminal configuration and no integrated biasing or protection circuitry. Its small-signal characteristics include f_T = 250 MHz at I_C = 20 mA, C_obo ≤ 8.0 pF, and h_ie = 2.0–8.0 kΩ depending on bias point.

It supports linear amplification and saturated switching modes, with verified performance across –55°C to +150°C junction temperature range. Switching behavior is characterized by delay, rise, storage, and fall times - though detailed timing data applies only to the PN2222A variant per the source document.

Key Specifications

Pinout & Package

PN2222 is housed in a TO-92 plastic package (Case 29, Style 1), with leads formed for through-hole mounting and marked "PN222x" on the body. The package has standardized mechanical dimensions per ANSI Y14.5M, including lead pitch of 2.54 mm and maximum height of 5.20 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose transistor applications.

Compared with PN2222, the PN2222A offers higher voltage ratings and guaranteed gain, making it a drop-in upgrade for new designs; BC547B provides higher gain at lower currents but lacks the current handling and ruggedness needed for power switching roles.

Availability

PN2222 is available at Aetrix Electronics and suitable for relay drivers, LED controllers, audio preamplifiers, and logic-level translators requiring stable component supply and long-term obsolescence management.

Supply support for PN2222 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 specializing in energy-efficient power and sensing solutions for automotive, industrial, and cloud infrastructure markets.

PN2222 belongs to onsemi's legacy general-purpose transistor product line, designed for broad compatibility in cost-sensitive analog and discrete digital interface applications across consumer, industrial, and communications equipment.

FAQ

What is the maximum collector-emitter voltage rating for PN2222?

The PN2222 has a maximum collector-emitter voltage (V_CEO) rating of 30 Vdc under open-base conditions. This value is confirmed in the Absolute Maximum Ratings table and must not be exceeded to prevent avalanche breakdown. Derating is required at elevated temperatures, and actual design margin should account for transient spikes and layout parasitics.

Is PN2222 pin-compatible with PN2222A?

Yes, PN2222 is pin-compatible with PN2222A - both use identical TO-92 package (Case 29, Style 1) with emitter-base-collector pinout (1-2-3). No PCB layout changes are required when substituting PN2222A for PN2222, though the PN2222A offers higher voltage ratings and guaranteed minimum h_FE.

What is the typical DC current gain (h_FE) of PN2222 at 10 mA collector current?

At I_C = 10 mA and V_CE = 10 V, the PN2222 exhibits h_FE ranging from 75 to 300 per the Electrical Characteristics table. The minimum specified value is 75, and typical curves show median gain near 150–200 under these conditions, making it suitable for moderate-gain switching and amplification tasks.

Can PN2222 be used in switching applications above 100 kHz?

Yes, PN2222 supports switching up to approximately 100 kHz in practical implementations due to its f_T of 250 MHz and measured rise/fall times (though full timing specs apply only to PN2222A). For reliable operation above 50 kHz, ensure adequate base drive, minimize trace inductance, and verify thermal stability under repetitive switching duty cycles.

What is the thermal resistance junction-to-ambient (R_θJA) for PN2222 in TO-92 package?

The PN2222 has a specified R_θJA of 200°C/W in free-air conditions. This value assumes standard PCB mounting with minimal copper area; actual thermal performance improves with added copper pour or heatsinking. At 625 mW dissipation, this yields a 125°C junction rise above ambient - requiring derating or forced cooling above 25°C ambient.