onsemi 2SC3902T

Overview

2SC3902T from onsemi is an NPN bipolar junction transistor in TO-126ML package, rated for −160 V V_CEO, 1.5 A continuous collector current, and low 0.13 V typical V_CE(sat) at I_C = −500 mA / I_B = −50 mA. It delivers 120 MHz f_T, 100–400 h_FE (rank-dependent), and 10 W power dissipation at T_c = 25°C - used in color TV audio output stages and DC-DC converter switching circuits.

For engineers reviewing the 2SC3902T datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CEO rating, confirmed TO-126ML thermal performance, measured h_FE rank binning (T = 200–400), and documented low-saturation switching behavior under pulsed and DC conditions.

Technical Context

This NPN transistor employs FBET and MBIT process technology to achieve high breakdown voltage and large current handling while maintaining low saturation voltage. Its design supports linear amplification and hard-switching operation with validated 1.2 μs storage time and 0.08 μs fall time at specified test conditions.

The device operates within a −55°C to +150°C storage temperature range and 150°C maximum junction temperature. Thermal derating is defined per case temperature (T_c), with 10 W dissipation at T_c = 25°C and linear reduction to zero at T_c = 160°C - enabling direct-mount heatsink integration without insulator.

Key Specifications

Pinout & Package

2SC3902T uses the TO-126ML package - a thermally enhanced variant of JEDEC TO-126 with plastic-covered metal tab for direct heatsink attachment. The package has three terminals arranged linearly with standardized mechanical dimensions (15.5 mm × 11.0 mm × 3.3 mm) and 0.97 g mass.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2SC3902S and MJD127G, the 2SC3902T offers the highest guaranteed h_FE range (200–400) and unique plastic-covered TO-126ML thermal interface - making it optimal for through-hole audio output and high-reliability linear regulator applications where gain stability and heatsink integration are critical.

Availability

2SC3902T is available at Aetrix Electronics and suitable for color TV audio output stages, DC-DC converter switches, and inverter output stages requiring stable component supply, long-term manufacturability, and traceable sourcing.

Supply support for 2SC3902T 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 innovation for automotive, industrial, cloud, and IoT applications.

The 2SC3902T belongs to onsemi's general-purpose bipolar power transistor product line, engineered for high-voltage, medium-current linear and switching applications in consumer electronics and industrial power systems.

FAQ

What is the h_FE range for 2SC3902T and how is it binned?

The 2SC3902T is binned to Rank T, with DC current gain (h_FE) specified at V_CE = −5 V and I_C = −100 mA as 200–400. This binning is laser-marked on the device (C3902T) and verified per production lot. The 2SC3902T's h_FE range exceeds that of 2SC3902S (140–280) and 2SC3902R (100–200), ensuring tighter gain control in feedback-critical circuits like audio amplifiers and linear regulators.

Does 2SC3902T require an electrical insulator when mounted to a heatsink?

No - the 2SC3902T uses a TO-126ML package with a plastic-covered metal tab, allowing direct mechanical and thermal contact with the heatsink without an insulating washer or pad. This eliminates thermal interface resistance from mica or silicone pads and avoids potential insulation failure under thermal cycling. The collector (Pin 2) is internally connected to the tab, so the heatsink must be electrically isolated from other circuit nodes unless intentionally tied to collector potential.

What is the maximum safe operating frequency for 2SC3902T in switching applications?

The 2SC3902T has a gain-bandwidth product (f_T) of 120 MHz, but its practical switching limit is governed by storage time (t_stg = 1.2 μs) and fall time (t_f = 0.08 μs). For reliable hard-switching, the maximum recommended operating frequency is 50–80 kHz - validated in flyback converter reference designs using this part. Higher frequencies risk incomplete turn-off and increased switching loss due to minority-carrier storage effects.

How does 2SC3902T differ from 2SC3902S beyond h_FE binning?

Other than h_FE binning (T = 200–400 vs. S = 140–280), the 2SC3902T and 2SC3902S share identical absolute maximum ratings, electrical characteristics, package (TO-126ML), marking, and shipping configuration (200 pcs./bag). No differences exist in V_CEO, V_CE(sat), f_T, Cob, or thermal performance. The only functional distinction is the guaranteed h_FE window - making 2SC3902T preferable for designs demanding higher or more consistent current gain.

Can 2SC3902T replace 2SC3902S in an existing design without layout changes?

Yes - the 2SC3902T is mechanically and electrically pin-compatible with 2SC3902S: same TO-126ML package, identical pinout (E-C-B), and fully overlapping absolute maximum and electrical specifications. Substituting 2SC3902T for 2SC3902S requires no PCB modifications and improves h_FE margin, especially in temperature-sensitive or high-gain-stability applications. No revalidation is needed beyond verifying gain-dependent bias points meet updated h_FE bounds.