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

onsemi 2N4923

Name: 2N4923
Brand: onsemi
SKU: 2N4923
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N4923

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: 2N4923.pdf

Description:: TRANS NPN 80V 1A TO-126

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2N4923 from onsemi is a medium-power plastic NPN silicon transistor designed for switching and amplifier driver circuits, with 80 V_CEO, 1.0 A continuous collector current, 30 W power dissipation at T_C = 25°C, and TO-225 package. It delivers low saturation voltage (V_CE(sat) ≤ 0.6 V at I_C = 1.0 A, I_B = 0.1 A) and operates across –65°C to +150°C junction temperature range.

For engineers reviewing the 2N4923 datasheet, pinout, applications, or equivalent options, this page provides verified electrical parameters, thermal derating behavior, safe operating area limits, and validated alternatives for industrial switching and linear amplification designs requiring robust SOA and Pb-free compliance.

Technical Context

The 2N4923 operates as a general-purpose bipolar junction transistor in active, saturation, and cutoff regions, supporting both linear amplification and hard-switching functions. Its DC current gain (h_FE) ranges from 10 (at I_C = 1.0 A) to 150 (at I_C = 50 mA), and its f_T is 3.0 MHz under specified small-signal conditions.

Thermal design is constrained by R_JC = 4.16°C/W max and a 0.24 W/°C power derating slope above 25°C case temperature. Safe operating area (SOA) is defined up to 150°C junction temperature, with second-breakdown-limited pulse curves valid for duty cycles ≤10%.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	80 Vdc - Maximum collector-emitter voltage before breakdown; defines upper rail limit in switching applications.
I_C (continuous)	1.0 Adc - Continuous collector current rating; sets base drive and heatsink sizing for sustained conduction.
P_D @ T_C = 25°C	30 W - Total power dissipation at 25°C case temperature; requires thermal interface and heatsinking for higher T_C.
V_CE(sat)	≤ 0.6 Vdc at I_C = 1.0 A, I_B = 0.1 A - Low saturation voltage minimizes conduction loss in switch-mode operation.
h_FE	10–150 - Wide DC current gain range enables flexible biasing across load currents from 50 mA to 1.0 A.
f_T	3.0 MHz - Unity-gain bandwidth supports audio-frequency amplification and moderate-speed switching.
R_JC	4.16°C/W max - Junction-to-case thermal resistance determines minimum thermal interface performance required.

Pinout & Package

2N4923 is housed in a TO-225 package (Case 77-09, Style 1) with three leads and an electrically connected metal tab (pins 2 and 4). The package is Pb-free and RoHS compliant.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Emitter	Main current exit path; connects to ground or low-side return in common-emitter configurations.
Pins 2 & 4	Collector	Shared collector terminal via metal tab; must be thermally and electrically connected to heatsink or PCB copper pour.
Pin 3	Base	Control input for current amplification; requires current-limiting resistor to set I_B per h_FE and load requirements.

Key Features

Feature	Design Value
Low V_CE(sat)	≤ 0.6 V at full 1.0 A load reduces power loss and self-heating during saturation.
Wide SOA	Validated up to 150°C junction temperature with pulse and DC limits-supports reliable operation under transient overloads.
High V_CEO	80 V enables use in 48 V industrial bus systems and flyback snubber circuits without derating.
Pb-free & RoHS	G-suffix confirms lead-free termination and compliance with EU RoHS Directive 2011/65/EU.
Complementary PNP pair	Designed as NPN counterpart to 2N4920G, enabling push-pull output stages with matched voltage ratings.

Applications

DC Motor Driver Stage	Industrial Relay Driver
Use Scenario: Driving 24–48 V DC brushed motors in factory automation controllers with PWM at ≤20 kHz. IC Role / Device Role / Timing Role: NPN switch in common-emitter configuration, sinking motor current through emitter-ground path. Use Value: 80 V_CEO withstands inductive kickback; 30 W dissipation supports 1 A continuous stall current with proper heatsinking.	Use Scenario: Activating 24 VDC industrial relays with coil resistance 100–500 Ω in PLC I/O modules. IC Role / Device Role / Timing Role: High-current saturated switch interfacing microcontroller GPIO to relay coil. Use Value: V_CE(sat) ≤ 0.6 V ensures minimal voltage drop across transistor, preserving relay pull-in margin.
Linear Audio Amplifier	Power Supply Pass Transistor
Use Scenario: Output stage in Class-A/B audio preamplifiers delivering ≤1 W into 8 Ω loads at frequencies up to 20 kHz. IC Role / Device Role / Timing Role: Linear amplifying device biased in active region with fixed emitter resistor and collector load. Use Value: h_FE ≥ 30 at 500 mA enables stable biasing; f_T = 3.0 MHz supports full audio bandwidth with gain margin.	Use Scenario: Series pass element in adjustable linear regulators supplying 1–1.5 A at ≤36 V input–output differential. IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output by dissipating excess input-output power. Use Value: R_JC = 4.16°C/W and 30 W rating allow thermal management within 50°C ambient rise using standard heatsinks.

DC Motor Driver Stage

Industrial Relay Driver

Use Scenario: Driving 24–48 V DC brushed motors in factory automation controllers with PWM at ≤20 kHz.

IC Role / Device Role / Timing Role: NPN switch in common-emitter configuration, sinking motor current through emitter-ground path.

Use Value: 80 V_CEO withstands inductive kickback; 30 W dissipation supports 1 A continuous stall current with proper heatsinking.

Use Scenario: Activating 24 VDC industrial relays with coil resistance 100–500 Ω in PLC I/O modules.

IC Role / Device Role / Timing Role: High-current saturated switch interfacing microcontroller GPIO to relay coil.

Use Value: V_CE(sat) ≤ 0.6 V ensures minimal voltage drop across transistor, preserving relay pull-in margin.

Linear Audio Amplifier

Power Supply Pass Transistor

Use Scenario: Output stage in Class-A/B audio preamplifiers delivering ≤1 W into 8 Ω loads at frequencies up to 20 kHz.

IC Role / Device Role / Timing Role: Linear amplifying device biased in active region with fixed emitter resistor and collector load.

Use Value: h_FE ≥ 30 at 500 mA enables stable biasing; f_T = 3.0 MHz supports full audio bandwidth with gain margin.

Use Scenario: Series pass element in adjustable linear regulators supplying 1–1.5 A at ≤36 V input–output differential.

IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output by dissipating excess input-output power.

Use Value: R_JC = 4.16°C/W and 30 W rating allow thermal management within 50°C ambient rise using standard heatsinks.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD44H11T4	TO-252 package; V_CEO = 80 V, I_C = 8 A, but h_FE min = 20 at 4 A - higher current capability, surface-mount only.	Requires PCB redesign for SMT layout; better suited for high-volume automated assembly than through-hole 2N4923.	Select when board space is constrained and peak current exceeds 1.0 A, accepting trade-off in thermal interface complexity.
BD139	TO-126 package; V_CEO = 80 V, I_C = 1.5 A, P_D = 12.5 W - lower power rating and different pinout (E-B-C vs E-C-B).	Not pin-compatible; requires trace rerouting and reduced thermal margin due to lower 12.5 W dissipation.	Choose only for cost-sensitive legacy designs where 12.5 W suffices and TO-126 footprint is already established.

Compared with MJD44H11T4 and BD139, the 2N4923 offers through-hole TO-225 mounting, verified 30 W dissipation with metal-tab thermal path, and consistent h_FE behavior across its 50 mA–1.0 A operating range-making it optimal for medium-power industrial drivers where mechanical robustness and thermal headroom are prioritized over miniaturization or ultra-high current.

Availability

2N4923 is available at Aetrix Electronics and suitable for industrial motor control, relay interface modules, linear regulator pass stages, and audio amplifier outputs requiring stable component supply and long-term manufacturability assurance.

Supply support for 2N4923 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, sensor, and logic solutions for automotive, industrial, and cloud infrastructure markets.

The 2N4923 belongs to onsemi's legacy general-purpose power transistor family, engineered for reliability in industrial switching and linear amplification where ruggedness, SOA integrity, and thermal stability outweigh high-frequency or ultra-low-loss requirements.

FAQ

What is the maximum continuous collector current rating for the 2N4923?

The 2N4923 has a maximum continuous collector current (I_C) rating of 1.0 A at T_C = 25°C, as specified in the Absolute Maximum Ratings table. This value is based on JEDEC current gain requirements and assumes adequate heatsinking to maintain case temperature at or below 25°C. At elevated case temperatures, derating applies at 0.24 W/°C.

Is the 2N4923 pin-compatible with other transistors in the 2N492x series?

Yes, the 2N4923 shares identical TO-225 package (Case 77-09, Style 1) and pinout (Emitter–Collector–Base on pins 1–2/4–3) with 2N4921G and 2N4922G. However, V_CEO, V_CB, and SOA boundaries differ across the series-2N4923 supports 80 V while 2N4921G is rated for 40 V-so substitution requires verification of voltage stress margins.

Does the 2N4923 have a documented safe operating area (SOA) curve?

Yes, Figure 5 in the official onsemi datasheet (Rev. 16, October 2024) provides the active-region SOA curve for the 2N4923, covering DC, 10 ms, 1 ms, 100 μs, and 10 μs pulse widths at T_J = 150°C. The curve defines simultaneous V_CE and I_C limits to prevent second breakdown and thermal runaway.

What is the thermal resistance from junction to case (R_JC) for the 2N4923?

The 2N4923 has a maximum junction-to-case thermal resistance (R_JC) of 4.16°C/W, measured under specified test conditions. This value assumes direct metal-to-metal contact between the TO-225 tab (pins 2 & 4) and heatsink, with thermal compound recommended to minimize interfacial resistance and achieve the lowest possible R_θJC.

Is the 2N4923 still recommended for new designs?

No-the official onsemi datasheet marks the 2N4923 as "DISCONTINUED" and states it is "not recommended for new design." While actively stocked and supported by Aetrix Electronics for legacy production and repair, designers should consult onsemi for modern alternatives such as the NSS series or MJD44H11T4 if initiating new development.

2N4923 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 A

Voltage - Collector Emitter Breakdown (Max):: 80 V

Vce Saturation (Max) @ Ib, Ic:: 600mV @ 100mA, 1A

Current - Collector Cutoff (Max):: 500µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 30 @ 500mA, 1V

Power - Max:: 30 W

Frequency - Transition:: 3MHz

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126

2N4923 FAQ

1.How can I place an order for 2N4923 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N4923 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 2N4923 reliable?

The price and inventory of 2N4923 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N4923 is usually 5 days.

3.What payment methods are accepted for 2N4923?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N4923 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N4923?

2N4923 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N4923 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 2N4923?

For technical support, including 2N4923 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N4923 requirements.

6.How does Aetrix verify that 2N4923 is sourced from the original manufacturer or authorized distributors?

All 2N4923 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 2N4923 meets industry standards.

7.What is the process for return or replacement of 2N4923?

All 2N4923 units undergo pre-shipment inspection (PSI). If there is an issue with 2N4923, 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 2N4923 part is unused and in its original packaging.

Return procedure for 2N4923:

1.Submit a request within 90 days.

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

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