onsemi 2SC3786

Overview

2SC3786 from SANYO is an NPN epitaxial planar silicon transistor designed for inductive load switching in motor drivers, relay drivers, and printer hammer drivers. It features a 60±10 V on-chip Zener diode between collector and base, 3 A DC collector current rating, 1.2 W (Tc=25°C) power dissipation, and high DC current gain (h_FE = 1000–4000 at I_C = 1.5 A, V_CE = 5 V).

For engineers reviewing the 2SC3786 datasheet, pinout, applications, or equivalent options, key selection considerations include its wide SOA (25 mJ single-pulse), 6 A peak collector current capability, collector-base Zener clamping, and TO-126LP package thermal performance under pulsed inductive loads.

Technical Context

The 2SC3786 operates as a medium-power NPN switching transistor with integrated 60±10 V collector-to-base Zener protection, enabling safe commutation of L loads without external snubbers. Its SOA is characterized up to 25 mJ (1 ms pulse, no heatsink), and it supports DC operation up to 1.2 W at T_c = 25°C.

Electrical behavior is defined by V_CEO = 50 V, V_CBO = 50 V, V_EBO = 6 V, and saturation voltages of V_CE(sat) = 1.5 V (I_C/I_B = 250) and V_BE(sat) = 2.4 V (I_C = 3 A). Switching times are t_on = 2.0 µs, t_stg = 3.5 µs, t_off = 0.7 µs under specified test conditions.

Key Specifications

Pinout & Package

Package: TO-126LP - 3-lead plastic power package with exposed collector tab for thermal mounting; footprint compatible with standard TO-126 heatsinks.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2SC3786, the 2SC4110 offers higher voltage margin but demands external protection circuitry, while the BU406 provides greater ruggedness at high voltage but sacrifices switching speed and board space efficiency-making 2SC3786 optimal for compact, fast-switching 24–48 V DC inductive driver designs.

Availability

2SC3786 is available at Aetrix Electronics and suitable for printer hammer drivers, relay interface modules, and solenoid actuator control systems requiring stable component supply and long-term industrial availability.

Supply support for 2SC3786 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

SANYO Electric Co., Ltd. was a Japanese semiconductor manufacturer specializing in power discrete devices, analog ICs, and optoelectronics before its acquisition by Panasonic in 2011.

The 2SC3786 belongs to SANYO's ENN2299A series of high-gain, Zener-clamped NPN transistors engineered specifically for reliable inductive load switching in office automation and industrial control equipment.

FAQ

What is the maximum continuous collector current rating for the 2SC3786?

The 2SC3786 has a maximum continuous collector current (I_C) rating of 3 A at T_c = 25°C. This rating assumes proper heatsinking; derating is required above 25°C case temperature per the PC–Ta curve in the datasheet. At ambient temperatures above 70°C, the device must be operated below 1 A to remain within safe thermal limits. The 2SC3786 also supports 6 A peak collector current for short pulses (≤1 ms), validated under SOA testing.

Does the 2SC3786 include built-in protection against inductive kickback?

Yes, the 2SC3786 integrates a 60 ± 10 V Zener diode between collector and base. This on-chip clamping structure safely dissipates flyback energy during turn-off of inductive loads such as relays and solenoids, eliminating the need for external clamp diodes in most standard driver configurations. The Zener is rated for repetitive operation under specified pulse conditions and contributes directly to the device's 25 mJ single-pulse SOA rating.

What package type does the 2SC3786 use, and how is thermal management handled?

The 2SC3786 uses the TO-126LP package-a 3-lead plastic power package with an exposed collector tab that serves as both electrical connection and thermal interface. The collector (Pin 2) is internally bonded to this metal tab, enabling direct mounting to a heatsink. Thermal resistance from junction-to-case (R_θJC) is optimized for this construction, allowing 1.2 W dissipation at T_c = 25°C. For sustained operation above 1 A, mechanical attachment to an aluminum heatsink is recommended.

Can the 2SC3786 be used in PWM motor control applications?

Yes, the 2SC3786 is suitable for PWM-based DC motor control at frequencies up to ~100 kHz, supported by its 180 MHz transition frequency (f_T) and fast switching times (t_on = 2.0 µs, t_off = 0.7 µs). Its low V_CE(sat) (≤1.5 V at I_C = 3 A) minimizes conduction losses, while the integrated Zener protects against back-EMF during PWM turn-off. For reliable operation, ensure base drive meets I_B ≥ I_C/250 and maintain adequate heatsinking during extended duty cycles.

What are the absolute maximum ratings for base-emitter voltage and collector-base voltage in the 2SC3786?

Per the official SANYO datasheet, the 2SC3786 has an absolute maximum V_EBO (emitter-base voltage) of 6 V and a V_CBO (collector-base voltage) of 50 V. These ratings define the maximum reverse-biased voltages allowable across those junctions without risk of avalanche breakdown. Notably, the on-chip Zener diode operates between collector and base at 60 ± 10 V-but this is a controlled forward-conduction feature, not a breakdown rating; exceeding 50 V across C–B in non-Zener bias conditions violates absolute maximum limits and may cause permanent damage to the 2SC3786.