onsemi 2N3903_D27Z

Overview

2N3903_D27Z from Fairchild Semiconductor is an NPN general-purpose bipolar junction transistor (BJT) designed for low-to-medium current amplification and switching applications up to 100 mA collector current. It features a V_CEO of 40 V, V_CBO of 60 V, and h_FE ranging from 20 to 150 depending on operating conditions, housed in a TO-92 plastic package with emitter-first tape-and-reel orientation (EOL code D27Z).

For engineers reviewing the 2N3903_D27Z datasheet, pinout, applications, or equivalent options, key selection considerations include its DC current gain profile across 0.1–100 mA, saturation voltage at defined drive levels, thermal resistance (R_θJA = 200 °C/W), noise figure (6.0 dB at 100 µA), and TO-92 mechanical compatibility for through-hole prototyping and production.

Technical Context

The 2N3903_D27Z operates as a silicon NPN BJT with a maximum junction temperature of +150 °C and storage range from –55 °C to +150 °C. Its small-signal h_fe reaches 200 at 1.0 mA and 10 V _VCE, while pulsed h_FE peaks near 500 at 10 mA and 25 °C. The device exhibits Cob = 4.0 pF and Cib = 8.0 pF at specified bias conditions, supporting audio-frequency and low-speed digital switching.

Switching performance is characterized by td = 35 ns, tr = 35 ns, ts = 175 ns, and tf = 50 ns under V_CC = 3.0 V, I_C = 10 mA, and I_B = 1.0 mA test conditions. Its V_BE(sat) ranges from 0.65 V to 0.95 V and V_CE(sat) from 0.2 V to 0.3 V across 10–50 mA loads, enabling predictable turn-on behavior in saturated switch designs.

Key Specifications

Pinout & Package

2N3903_D27Z is supplied in a standard TO-92 plastic package (JEDEC TO-92 variant), with leads arranged in straight configuration and emitter-first orientation per EOL code D27Z tape-and-reel specification. The package has a height of 0.928 ± 0.025 inches and uses axial lead form with flat side facing down during taping.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2N3904 and BC547B, the 2N3903_D27Z offers balanced gain, proven thermal stability, and strict adherence to the E-B-C pinout-making it the preferred choice for maintaining existing board designs, educational kits, and cost-driven consumer electronics where 40 V V_CEO and 625 mW dissipation meet system requirements.

Availability

2N3903_D27Z is available at Aetrix Electronics and suitable for audio preamplifiers, microcontroller interface drivers, discrete logic inverters, and current mirror references requiring stable component supply and long-term manufacturability.

Supply support for 2N3903_D27Z 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 BJT portfolio remains widely deployed in industrial and educational applications.

The 2N3903_D27Z belongs to Fairchild's classic 2N390x NPN transistor family, engineered for general-purpose amplification and switching in cost-sensitive, reliability-critical designs where TO-92 packaging and predictable h_FE behavior are essential.

FAQ

What is the pin configuration of the 2N3903_D27Z?

The 2N3903_D27Z uses the standard TO-92 package with Emitter-Base-Collector (E-B-C) pinout when viewed with the flat side facing outward and leads pointing downward. Pin 1 is Emitter, Pin 2 is Base, and Pin 3 is Collector-consistent with JEDEC TO-92 and confirmed by Fairchild's D27Z tape-and-reel specification showing emitter-first orientation.

Does the 2N3903_D27Z support switching applications up to 100 mA?

Yes, the 2N3903_D27Z is rated for continuous collector current up to 200 mA and specified for switching applications up to 100 mA. Its V_CE(sat) remains ≤0.3 V at I_C = 50 mA / I_B = 5 mA, and switching times (td = 35 ns, ts = 175 ns) are validated under those conditions-making it suitable for relay drivers, LED arrays, and low-frequency PWM control in the 2N3903_D27Z's operational envelope.

How does the noise performance of the 2N3903_D27Z compare to other general-purpose BJTs?

The 2N3903_D27Z has a measured noise figure of 6.0 dB at V_CE = 5.0 V, I_C = 100 µA, R_S = 1.0 kΩ, and 10 Hz–15.7 kHz bandwidth-comparable to the 2N3904 but lower than older devices like the 2N2222A (typically 10 dB). This makes the 2N3903_D27Z a viable option for low-noise preamplifier stages where cost and availability outweigh ultra-low-noise requirements.

Can the 2N3903_D27Z be used in place of the 2N3904 in existing designs?

The 2N3903_D27Z shares the same TO-92 package, pinout, and absolute maximum ratings as the 2N3904, but its h_FE minimum is lower (30 vs 100 at I_C = 10 mA). It can replace the 2N3904 in saturated switching applications with sufficient base drive, but may require gain verification in linear amplifier stages-always validate bias point and AC response when substituting 2N3903_D27Z for 2N3904.

What thermal derating applies to the 2N3903_D27Z at elevated ambient temperatures?

The 2N3903_D27Z has a thermal derating factor of 5.0 mW/°C above 25 °C ambient, based on its 625 mW maximum power dissipation at T_A = 25 °C and R_θJA = 200 °C/W. At 75 °C ambient, its usable power drops to 375 mW; full derating must be applied in enclosed or high-temperature environments to maintain junction temperature ≤150 °C in the 2N3903_D27Z.