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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi 2SC3902S

Name: 2SC3902S
Brand: onsemi
SKU: 2SC3902S
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2SC3902S

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: 2SC3902S.pdf

Description:: TRANS NPN 160V 1.5A TO-126ML

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2SC3902S from onsemi is an NPN bipolar junction transistor (BJT) designed for high-voltage switching and power amplification in consumer electronics. It delivers 160 V V_CEO, 1.5 A continuous collector current, low 0.13 V typical V_CE(sat) at I_C = 500 mA, 120 MHz f_T, and operates up to 150 °C junction temperature - used in color TV audio output stages and DC-DC inverters.

For engineers reviewing the 2SC3902S datasheet, pinout, applications, or equivalent options, this page provides verified package mapping (TO-126ML), terminal roles, hFE ranking (S-grade: 140–280), thermal derating curves, and direct alternatives with documented electrical differences.

Technical Context

This NPN transistor employs FBET and MBIT process technology to achieve high breakdown voltage and low saturation voltage simultaneously. Its TO-126ML package integrates a plastic-covered heat sink, eliminating need for electrical insulation during mounting - enabling direct heatsink attachment without isolation washers.

The device is characterized across temperature (–25°C to +75°C) and bias conditions: h_FE is specified at both I_C = 10 mA (min 90) and I_C = 100 mA (min 100), while switching times (t_on = 0.04 μs, t_stg = 1.2 μs, t_f = 0.08 μs) support medium-frequency switching applications up to ~1 MHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	160 V - supports operation in 120–150 V DC bus applications without derating
I_C (continuous)	1.5 A - sufficient for audio output drivers and low-power SMPS primary-side switches
V_CE(sat) (typ)	0.13 V @ I_C = 500 mA, I_B = 50 mA - reduces conduction loss and self-heating in linear/switching modes
f_T	120 MHz - enables stable gain in RF driver or broadband amplifier stages up to ~20 MHz
h_FE (S grade)	140–280 @ V_CE = –5 V, I_C = –100 mA - ensures predictable current gain in feedback-controlled circuits
P_C @ T_c = 25°C	10 W - allows high-power dissipation when mounted on heatsink; derates to 1.5 W at T_a = 25°C free-air
C_ob	14 pF @ V_CB = –10 V - limits Miller capacitance impact in switching transitions

Pinout & Package

2SC3902S uses the TO-126ML package - a molded plastic variant of JEDEC TO-126 with integrated heat sink flange. The case is electrically connected to the collector (Pin 2), enabling direct thermal coupling to heatsinks without insulating hardware.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current exit path; referenced to ground or negative rail in common-emitter configurations
2	Collector	Main current input; tied to heatsink flange - must be isolated from chassis if circuit ground differs
3	Base	Control terminal; requires current-limited drive (I_B ≤ 50 mA) for safe saturation

Key Features

Feature	Design Value
High V_CEO rating	160 V enables use in CRT deflection yoke drivers and flyback converter switches without snubbers
Low V_CE(sat)	0.13 V typical minimizes power loss and thermal stress in Class AB audio output stages
Plastic-covered heat sink	Eliminates need for mica washers or silicone pads - simplifies mechanical assembly and improves thermal R_θJC
S-grade h_FE binning	140–280 range ensures consistent gain matching in push-pull pairs or differential amplifiers
FBET/MBIT process	Provides superior ruggedness against secondary breakdown and improved safe operating area (SOA)

Applications

Color TV Audio Output Stage	DC-DC Inverter Primary Switch
Use Scenario: Driving loudspeaker loads in analog CRT television audio amplifiers with ±24 V rails. IC Role / Device Role / Timing Role: NPN power switch in complementary Class AB output stage; handles peak currents up to 1.2 A. Use Value: Low V_CE(sat) reduces crossover distortion and thermal drift; TO-126ML flange mounts directly to chassis for passive cooling.	Use Scenario: Switching 120 V DC bus in offline half-bridge inverters for backlight CCFL drivers. IC Role / Device Role / Timing Role: High-voltage NPN switch controlling primary winding current; operated at 20–50 kHz. Use Value: 160 V V_CEO provides 20% margin over 120 V bus; fast switching (t_f = 0.08 μs) limits transition losses.
Linear Regulator Pass Element	Industrial Relay Driver
Use Scenario: Series pass transistor in adjustable 0–30 V, 1.2 A bench power supply. IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output via base bias; dissipates up to 8 W. Use Value: 10 W P_C at T_c = 25°C supports heatsink-mounted operation; SOA robustness prevents thermal runaway.	Use Scenario: Driving 24 V DC industrial relays with coil resistance ~200 Ω requiring 120 mA hold current. IC Role / Device Role / Timing Role: Saturated switch interfacing microcontroller GPIO to relay coil; driven with 12 mA base current. Use Value: h_FE ≥ 140 ensures full saturation at low drive; V_CE(sat) ≤ 0.45 V guarantees reliable relay pull-in under worst-case conditions.

Color TV Audio Output Stage

DC-DC Inverter Primary Switch

Use Scenario: Driving loudspeaker loads in analog CRT television audio amplifiers with ±24 V rails.

IC Role / Device Role / Timing Role: NPN power switch in complementary Class AB output stage; handles peak currents up to 1.2 A.

Use Value: Low V_CE(sat) reduces crossover distortion and thermal drift; TO-126ML flange mounts directly to chassis for passive cooling.

Use Scenario: Switching 120 V DC bus in offline half-bridge inverters for backlight CCFL drivers.

IC Role / Device Role / Timing Role: High-voltage NPN switch controlling primary winding current; operated at 20–50 kHz.

Use Value: 160 V V_CEO provides 20% margin over 120 V bus; fast switching (t_f = 0.08 μs) limits transition losses.

Linear Regulator Pass Element

Industrial Relay Driver

Use Scenario: Series pass transistor in adjustable 0–30 V, 1.2 A bench power supply.

IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output via base bias; dissipates up to 8 W.

Use Value: 10 W P_C at T_c = 25°C supports heatsink-mounted operation; SOA robustness prevents thermal runaway.

Use Scenario: Driving 24 V DC industrial relays with coil resistance ~200 Ω requiring 120 mA hold current.

IC Role / Device Role / Timing Role: Saturated switch interfacing microcontroller GPIO to relay coil; driven with 12 mA base current.

Use Value: h_FE ≥ 140 ensures full saturation at low drive; V_CE(sat) ≤ 0.45 V guarantees reliable relay pull-in under worst-case conditions.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD127G	Higher V_CEO (100 V), lower I_C (2 A), TO-252 package, no integrated heatsink	Requires external heatsink and insulator; better suited for PCB-mounted SMT designs	Select when surface-mount layout and tighter board space are priorities over mechanical mounting simplicity
2SC4110	Same TO-126ML package, higher f_T (200 MHz), lower V_CE(sat) (0.1 V typ), but lower V_CEO (120 V)	Not suitable for >120 V bus applications; preferred in high-speed switching where voltage margin is adequate	Choose when operating below 100 V and faster switching or lower conduction loss is critical

Compared with MJD127G and 2SC4110, the 2SC3902S uniquely balances 160 V capability, low saturation voltage, and integrated heatsink - making it optimal for through-hole, heatsink-coupled designs in legacy consumer power stages where reliability and thermal simplicity outweigh SMT density or ultra-high speed.

Availability

2SC3902S is available at Aetrix Electronics and suitable for color TV repair, industrial relay control, and analog power supply design requiring stable component supply, long-lifecycle availability, and legacy-compatible packaging.

Supply support for 2SC3902S 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 specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and consumer markets.

The 2SC3902S belongs to onsemi's legacy bipolar power transistor family engineered for high-reliability analog switching in cost-sensitive, thermally constrained applications - particularly CRT-based consumer electronics and industrial controls.

FAQ

What is the hFE rank designation for 2SC3902S?

The "S" suffix in 2SC3902S denotes the h_FE bin: 140–280 at V_CE = –5 V and I_C = –100 mA. This mid-range gain grade ensures predictable current amplification in feedback circuits without excessive variability. The 2SC3902S is distinct from the "T" grade (200–400) and "R" grade (100–200), and its h_FE is guaranteed per onsemi's No.2101-2/7 specification sheet.

Is 2SC3902S pin-compatible with 2SA1507S?

No - 2SC3902S (NPN) and 2SA1507S (PNP) share the same TO-126ML package and pinout (Emitter–Collector–Base), but they are complementary devices, not pin-compatible replacements. Their electrical polarities are inverted: 2SC3902S sinks current into the collector, while 2SA1507S sources it. Using them interchangeably without circuit redesign will cause functional failure.

Can 2SC3902S be used without a heatsink?

Yes, but only at reduced power: 2SC3902S is rated for 1.5 W in free-air (T_a = 25°C). For continuous operation above ~300 mW, a heatsink is required. The TO-126ML flange is collector-connected, so any heatsink must be electrically isolated unless the collector node is at system ground potential - unlike standard TO-126, no separate insulator is needed due to the molded plastic heat sink layer.

What is the maximum pulsed collector current for 2SC3902S?

The 2SC3902S supports I_CP = 2.5 A for short-duration pulses (≤100 ms, duty cycle ≤1%), as specified in the Absolute Maximum Ratings table. This rating assumes case temperature remains ≤25°C and is validated using the test circuit in Figure 1 of the datasheet (No.2101-3/7). Exceeding this value risks secondary breakdown, especially at high V_CE.

Does 2SC3902S meet RoHS requirements?

Yes - the 2SC3902S is marked "Pb Free" in the Ordering Information table and complies with RoHS Directive 2011/65/EU. Lead-free soldering profiles compatible with SnAgCu (SAC305) are supported, and the device undergoes onsemi's standard halogen-free and green material qualification per J-STD-020.

2SC3902S Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 1.5 A

Voltage - Collector Emitter Breakdown (Max):: 160 V

Vce Saturation (Max) @ Ib, Ic:: 450mV @ 50mA, 500mA

Current - Collector Cutoff (Max):: 1µA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 100mA, 5V

Power - Max:: 1.5 W

Frequency - Transition:: 120MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126ML

2SC3902S FAQ

1.How can I place an order for 2SC3902S through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SC3902S on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 2SC3902S reliable?

The price and inventory of 2SC3902S are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SC3902S is usually 5 days.

3.What payment methods are accepted for 2SC3902S?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SC3902S transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SC3902S?

2SC3902S orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SC3902S order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 2SC3902S?

For technical support, including 2SC3902S datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SC3902S requirements.

6.How does Aetrix verify that 2SC3902S is sourced from the original manufacturer or authorized distributors?

All 2SC3902S products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 2SC3902S meets industry standards.

7.What is the process for return or replacement of 2SC3902S?

All 2SC3902S units undergo pre-shipment inspection (PSI). If there is an issue with 2SC3902S, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 2SC3902S part is unused and in its original packaging.

Return procedure for 2SC3902S:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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