onsemi 2N4401_S00Z

Overview

2N4401_S00Z from ON Semiconductor is a TO-92 packaged NPN bipolar junction transistor designed for medium-power amplification and switching applications with continuous collector current up to 600 mA, V_CEO = 40 V, and DC current gain (h_FE) ranging from 40 to 300 at I_C = 1.0–150 mA. It operates across –55 °C to +150 °C and is commonly used in discrete logic-level switching, relay drivers, and low-frequency amplifier stages.

For engineers reviewing the 2N4401_S00Z datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-92 mechanical form factor, saturation voltage performance at 150 mA/15 mA drive, thermal resistance (R_θJA = 200 °C/W), and suitability for non-critical industrial signal conditioning and load control circuits.

Technical Context

The 2N4401_S00Z functions as a general-purpose silicon NPN BJT with fixed emitter-base and collector-base junction structures optimized for linear amplification and saturated switching. Its h_FE exhibits strong current dependency-ranging from 40 at 1 mA to 100 at 150 mA-and supports reliable turn-on/turn-off timing (t_d = 15 ns, t_s = 225 ns) under V_CC = 30 V conditions.

Thermal design relies on its 625 mW total power dissipation at 25 °C, derating linearly at 5.0 mW/°C above ambient. The device's f_T of 250 MHz at I_C = 20 mA confirms usable RF capability up to low-VHF, while C_cb = 6.5 pF and C_eb = 30 pF define its small-signal capacitance profile at specified bias points.

Key Specifications

Pinout & Package

2N4401_S00Z uses the industry-standard TO-92 package (JEDEC TO-92 compliant, straight lead configuration). Pin identification follows the EBC (Emitter–Base–Collector) sequence when viewing the flat side with leads downward and left-to-right orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN switching and amplification applications.

Compared with PN2222A and BC547B, the 2N4401_S00Z delivers balanced performance: sufficient current headroom for industrial switching, predictable gain across 1–150 mA, and TO-92 compatibility without over-spec'ing cost or thermal margin.

Availability

2N4401_S00Z is available at Aetrix Electronics and suitable for relay driver circuits, DC motor control stages, audio pre-amplifier designs, and LED current regulation requiring stable component supply and long-term obsolescence management.

Supply support for 2N4401_S00Z 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 discrete devices for automotive, industrial, and consumer applications.

The 2N4401_S00Z belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line, engineered for cost-sensitive, high-reliability discrete switching and amplification in non-automotive industrial systems.

FAQ

What is the maximum continuous collector current rating for the 2N4401_S00Z?

The 2N4401_S00Z has a maximum continuous collector current (I_C) rating of 600 mA at T_A = 25 °C. This rating assumes proper PCB thermal management; derating is required above 25 °C at 5.0 mW/°C. Operation beyond this limit risks thermal runaway or permanent junction damage, especially under sustained DC or high-duty-cycle PWM loads.

Does the 2N4401_S00Z have a documented pinout configuration, and what is it?

Yes, the 2N4401_S00Z uses the standard TO-92 package with EBC (Emitter–Base–Collector) pinout when viewed from the flat side with leads pointing downward and arranged left-to-right. This matches JEDEC TO-92 mechanical specifications and is electrically identical to the 2N2222A and PN2222 pin assignments, enabling direct board-level substitution in most through-hole layouts.

What is the typical DC current gain (h_FE) of the 2N4401_S00Z at 150 mA collector current?

The 2N4401_S00Z exhibits a typical DC current gain (h_FE) of 100 at I_C = 150 mA, V_CE = 1.0 V, and T_A = 25 °C. The datasheet specifies a minimum of 40 and maximum of 300 in this condition, reflecting process variation. Designers should use 100 as the nominal value for base resistor calculations but verify worst-case drive margin using the 40 minimum.

Can the 2N4401_S00Z be used in audio amplifier applications, and what supports that use?

Yes, the 2N4401_S00Z is suitable for low-noise audio pre-amplifier stages due to its f_T of 250 MHz, h_fe of 40–500 at 1.0 mA, and low output admittance (h_oe = 1.0–30 μmhos). Its small-signal parameters and stable gain across 20 Hz–20 kHz-verified in Figure 12–14 of the official datasheet-support clean voltage amplification without oscillation or distortion in common-emitter configurations.

What is the thermal resistance (R_θJA) of the 2N4401_S00Z, and how does it affect PCB layout?

The 2N4401_S00Z has a junction-to-ambient thermal resistance (R_θJA) of 200 °C/W on a standard FR-4 PCB (76 mm × 114 mm, 1.57 mm thick, minimum land pattern). This means a 625 mW dissipation raises junction temperature by 125 °C above ambient. To maintain T_J ≤ 150 °C, keep ambient below 25 °C or increase copper area-especially on the collector pad-to reduce effective R_θJA.