onsemi 2N4403NLBU

Overview

2N4403NLBU from Fairchild Semiconductor is a PNP general-purpose bipolar junction transistor used as an amplifier and switch in low-to-medium power linear and switching circuits, with V_CEO = 40 V, I_C = 600 mA, h_FE = 30–300 (at I_C = 0.1–500 mA), f_T = 200 MHz, and TO-92 package. It operates across –55°C to +150°C and supports applications such as signal inversion, relay driving, and discrete logic interfacing.

For engineers reviewing the 2N4403NLBU datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP polarity, guaranteed V_CEO/V_CBO = 40 V rating, confirmed 600 mA continuous collector current capability, thermal resistance R_θJA = 200°C/W on standard FR-4, and documented switching times (t_d = 15 ns, t_r = 20 ns, t_s = 225 ns, t_f = 30 ns) under defined test conditions.

Technical Context

The 2N4403NLBU implements a silicon planar epitaxial PNP BJT structure optimized for general-purpose amplification and saturated switching. Its DC current gain (h_FE) varies from 30 at I_C = 500 mA to 300 at I_C = 1.0 mA, and its small-signal parameters include h_ie = 1.5–15 kΩ and h_fe = 60–500 at 1 kHz, supporting stable biasing in common-emitter configurations.

Switching performance is characterized under pulsed conditions (pulse width ≤ 300 µs, duty cycle ≤ 2.0%) with V_CC = 30 V, I_C = 150 mA, and I_B1 = I_B2 = 15 mA. The device exhibits C_cb = 8.5 pF and C_eb = 30 pF at specified reverse-bias voltages, enabling predictable high-frequency response up to its 200 MHz f_T.

Key Specifications

Pinout & Package

2N4403NLBU is housed in a through-hole TO-92 package with standardized lead orientation: flat side facing viewer, leads downward, left-to-right pin order is Collector (C), Base (B), Emitter (E).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose amplifier applications.

Compared with MPSA92 and BC557, the 2N4403NLBU uniquely balances 40 V breakdown, 600 mA current handling, and 200 MHz f_T, making it optimal for medium-power switching where both voltage margin and current drive are simultaneously required.

Availability

2N4403NLBU is available at Aetrix Electronics and suitable for relay driver circuits, discrete logic inverters, LED current sinks, and linear regulator pass elements requiring stable component supply and long-term industrial availability.

Supply support for 2N4403NLBU 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016; its legacy products remain widely deployed in industrial and automotive systems.

The 2N4403NLBU belongs to Fairchild's general-purpose bipolar transistor family, designed specifically for cost-sensitive, medium-speed switching and linear amplification in non-critical industrial control, consumer electronics, and power supply auxiliary circuits.

FAQ

What is the maximum continuous collector current rating for the 2N4403NLBU?

The 2N4403NLBU has a maximum continuous collector current (I_C) rating of 600 mA at T_A = 25°C. This value decreases with rising ambient temperature per its thermal derating curve (5.0 mW/°C above 25°C). Operation above this limit risks thermal runaway or permanent degradation. Always verify actual I_C in circuit context using worst-case V_CE and duty cycle.

Is the 2N4403NLBU pin-compatible with the MMBT4403 SOT-23 variant?

No, the 2N4403NLBU is not pin-compatible with the MMBT4403. The 2N4403NLBU uses a TO-92 package with C-B-E lead order (left-to-right, flat side facing), while the MMBT4403 uses SOT-23 with different pinout (typically E-B-C). PCB layout, footprint, and soldering process differ fundamentally; direct substitution requires mechanical and electrical redesign.

What is the typical storage time (t_s) of the 2N4403NLBU under standard switching conditions?

The 2N4403NLBU has a typical storage time (t_s) of 225 ns when tested at V_CC = 30 V, I_C = 150 mA, and I_B1 = I_B2 = 15 mA. This parameter reflects minority carrier removal delay during turn-off and directly impacts maximum usable switching frequency in saturated-mode applications like relay drivers or PWM dimming circuits.

Does the 2N4403NLBU meet RoHS compliance requirements?

Yes, the 2N4403NLBU is RoHS-compliant per the original Fairchild documentation (Rev. C datasheet) and conforms to EU Directive 2011/65/EU. It contains no lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), or polybrominated diphenyl ethers (PBDE) above threshold limits. Full compliance documentation is available upon request from Aetrix Electronics.

Can the 2N4403NLBU be used in linear amplifier configurations with stable DC bias?

Yes, the 2N4403NLBU supports stable DC-biased linear amplification. Its h_FE ranges from 30 to 300 across I_C = 0.1–500 mA, and small-signal parameters (h_ie = 1.5–15 kΩ, h_fe = 60–500 at 1 kHz) are characterized for common-emitter operation. Use emitter degeneration and temperature-compensated biasing to maintain Q-point stability over –55°C to +150°C.