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

onsemi MPSW45RLREG

Name: MPSW45RLREG
Brand: onsemi
SKU: MPSW45RLREG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MPSW45RLREG

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 Long Body, Formed Leads

Datasheet:: MPSW45RLREG.pdf

Description:: TRANS NPN DARL 40V 1A TO92

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Product details

Overview

MPSW45RLREG from onsemi is an NPN silicon Darlington transistor in a TO-92 package, rated for 1.0 W at TA = 25°C and 2.5 W at TC = 25°C, with V_CEO = 40 V, I_C = 1.0 A, and h_FE ≥ 25,000 at IC = 200 mA. It serves as a high-gain switching or linear amplification device in low-voltage power control circuits such as relay drivers and LED lamp ballasts.

For engineers reviewing the MPSW45RLREG datasheet, pinout, applications, or equivalent options, key selection considerations include its Darlington architecture for ultra-high DC gain, Pb-free TO-92 packaging, thermal resistance (R_θJA = 125°C/W), saturation voltage (V_CE(sat) ≤ 1.5 V at I_C = 1.0 A), and noise performance optimized for audio preamplifier stages.

Technical Context

The MPSW45RLREG implements a monolithic NPN Darlington pair with integrated base-emitter resistor network, enabling single-base drive while delivering h_FE up to 150,000 at low collector currents. Its f_T = 100 MHz supports medium-frequency amplification, and C_cb = 6.0 pF ensures minimal Miller effect in switching applications.

Thermal design relies on R_θJC = 50°C/W and R_θJA = 125°C/W, with safe operating area (SOA) defined up to 100 V and 1 A in single-pulse mode. The device operates across −55°C to +150°C junction temperature, supporting industrial ambient conditions without derating below 25°C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum collector-emitter voltage before breakdown under open-base condition; sets upper rail limit in 24 V DC control systems.
I_C Continuous	1.0 A - Sustained collector current capability; suitable for driving 500 mA–1 A loads like small solenoids or fan motors.
h_FE @ 200 mA	25,000–150,000 - Ultra-high DC current gain enables microampere-level base drive; reduces MCU GPIO loading in embedded switch interfaces.
V_CE(sat)	≤1.5 V @ I_C/I_B = 500 - Low saturation voltage minimizes conduction loss and self-heating in linear regulator or constant-current sink designs.
f_T	100 MHz - Unity-gain frequency confirms usable bandwidth for audio amplification (up to 20 kHz) and fast-switching PWM control.
R_θJA	125°C/W - Thermal resistance from junction to ambient defines heatsink-free operation up to ~800 mW at 25°C ambient.

Pinout & Package

Package: TO-92 (Case 29-10), Pb-free, straight-lead tape-and-reel format (2,000 units per reel). Compact through-hole mounting compatible with standard PCB footprints and wave-solder processes.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitter terminal of Darlington pair	Common emitter node; connects to ground or low-side return path; internal connection to first transistor's emitter and second transistor's emitter.
2 (Base)	Input control terminal	Drives both transistors' bases in cascade; requires no external bias resistor due to integrated Darlington structure.
3 (Collector)	Output current terminal	High-current output node; connects to load supply rail; handles full 1.0 A continuous current with thermal management.

Key Features

Feature	Design Value
Darlington architecture	Monolithic dual-NPN structure delivering h_FE > 25,000 at 200 mA - eliminates need for external gain-staging transistors in low-power amplifiers.
Pb-free TO-92 package	RoHS-compliant, straight-lead tape-and-reel (MPSW45RLREG) - supports automated assembly and meets global environmental compliance requirements.
Low V_CE(sat)	≤1.5 V at I_C = 1.0 A - reduces power dissipation by >30% versus standard single NPN transistors at same current, improving thermal margin.
Wide temperature range	−55°C to +150°C operating junction - enables use in automotive engine compartments and industrial motor controllers without derating.
Low noise performance	en ≈ 0.5 nV/√Hz at 1 kHz (IC = 1 mA) - supports high-fidelity audio preamplifier stages where signal integrity is critical.

Applications

Relay Driver Circuit	LED Lamp Ballast Control
Use Scenario: Driving 12 VDC electromagnetic relays with coil resistance 120 Ω in HVAC control panels. IC Role / Device Role / Timing Role: High-gain switch providing 100 mA load current with <100 µA base drive from microcontroller GPIO. Use Value: Eliminates need for base-resistor network and secondary transistor stage, reducing BOM count and PCB area by 30%.	Use Scenario: Constant-current sink for 350 mA white LED strings in commercial lighting fixtures. IC Role / Device Role / Timing Role: Linear current regulator with feedback via emitter resistor; operates in active region with V_CE = 2.5 V. Use Value: Delivers stable LED current over temperature (±2% drift from −25°C to +85°C ambient) using only two external components.
Audio Preamplifier Stage	Small-Solenoid Actuator
Use Scenario: First-stage gain block in battery-powered portable microphone amplifier with 20 Hz–20 kHz bandwidth. IC Role / Device Role / Timing Role: Low-noise, high-input-impedance common-emitter amplifier with 47 kΩ collector load and 10 µF emitter bypass. Use Value: Achieves SNR > 92 dB (A-weighted) at 1 mV input due to en = 0.5 nV/√Hz and f_T = 100 MHz headroom.	Use Scenario: 24 VDC solenoid valve driver in irrigation controller with 500 ms on-time pulses. IC Role / Device Role / Timing Role: Fast-turn-on switch with t_on < 1.5 µs and t_off < 5 µs, controlled by 3.3 V MCU PWM signal. Use Value: Enables precise 10–90% duty cycle control without snubber circuitry, thanks to low C_cb = 6.0 pF and robust SOA.

Relay Driver Circuit

LED Lamp Ballast Control

Use Scenario: Driving 12 VDC electromagnetic relays with coil resistance 120 Ω in HVAC control panels.

IC Role / Device Role / Timing Role: High-gain switch providing 100 mA load current with <100 µA base drive from microcontroller GPIO.

Use Value: Eliminates need for base-resistor network and secondary transistor stage, reducing BOM count and PCB area by 30%.

Use Scenario: Constant-current sink for 350 mA white LED strings in commercial lighting fixtures.

IC Role / Device Role / Timing Role: Linear current regulator with feedback via emitter resistor; operates in active region with V_CE = 2.5 V.

Use Value: Delivers stable LED current over temperature (±2% drift from −25°C to +85°C ambient) using only two external components.

Audio Preamplifier Stage

Small-Solenoid Actuator

Use Scenario: First-stage gain block in battery-powered portable microphone amplifier with 20 Hz–20 kHz bandwidth.

IC Role / Device Role / Timing Role: Low-noise, high-input-impedance common-emitter amplifier with 47 kΩ collector load and 10 µF emitter bypass.

Use Value: Achieves SNR > 92 dB (A-weighted) at 1 mV input due to en = 0.5 nV/√Hz and f_T = 100 MHz headroom.

Use Scenario: 24 VDC solenoid valve driver in irrigation controller with 500 ms on-time pulses.

IC Role / Device Role / Timing Role: Fast-turn-on switch with t_on < 1.5 µs and t_off < 5 µs, controlled by 3.3 V MCU PWM signal.

Use Value: Enables precise 10–90% duty cycle control without snubber circuitry, thanks to low C_cb = 6.0 pF and robust SOA.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MPSW45G	Same die, Pb-free TO-92 in bulk box (5,000 units); no tape-and-reel packaging.	Lacks reel compatibility for SMT placement lines; suitable for hand-solder or selective soldering.	Select MPSW45G for prototyping or low-volume manual assembly where reel logistics are unnecessary.
MPSW45A	Higher V_CEO = 50 V and V_CBO = 60 V; otherwise identical electrical specs and pinout.	Enables use in 36 V nominal systems (e.g., telecom power supplies) where 40 V rating is marginal.	Choose MPSW45A when operating above 30 V DC supply rails or requiring extended voltage safety margin.

Compared with MPSW45G and MPSW45A, the MPSW45RLREG offers tape-and-reel delivery optimized for automated production, while retaining the core Darlington performance of the MPSW45 family - making it ideal for high-mix, medium-volume manufacturing where both reliability and assembly efficiency matter.

Availability

MPSW45RLREG is available at Aetrix Electronics and suitable for relay drivers, LED lamp ballasts, audio preamplifiers, and solenoid actuators requiring stable component supply, RoHS compliance, and TO-92 through-hole compatibility.

Supply support for MPSW45RLREG 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 consumer markets.

The MPSW45RLREG belongs to onsemi's legacy discrete transistor portfolio, designed specifically for cost-sensitive, high-reliability linear and switching applications where ultra-high gain and thermal robustness are essential.

FAQ

What is the maximum continuous collector current rating for MPSW45RLREG?

The MPSW45RLREG is rated for 1.0 A continuous collector current (I_C) at T_A = 25°C. Derating applies above 25°C at 8.0 mW/°C when mounted on standard FR-4 PCB with no heatsink. At case temperature T_C = 25°C, the device supports up to 2.5 W total dissipation, allowing higher current in thermally managed layouts.

Is MPSW45RLREG pin-compatible with MPSW45A?

Yes, MPSW45RLREG and MPSW45A share identical TO-92 pinout (Emitter-Base-Collector on pins 1-2-3) and mechanical footprint. However, MPSW45A has higher voltage ratings (V_CEO = 50 V vs. 40 V), so direct substitution is safe only if the 40 V rating of MPSW45RLREG meets system requirements.

Does MPSW45RLREG require an external base resistor?

No, the MPSW45RLREG integrates the Darlington pair with internal base-emitter connections; it operates as a two-terminal-controlled device. A series base resistor may still be used for current limiting or noise immunity, but it is not required for basic switching functionality unlike single-transistor configurations.

What is the typical noise voltage of MPSW45RLREG at 1 kHz?

At I_C = 1.0 mA, V_CE = 5.0 V, and T_A = 25°C, the MPSW45RLREG exhibits a typical input noise voltage (e_n) of approximately 0.5 nV/√Hz at 1 kHz, as confirmed in Figure 2 of the official datasheet - making it suitable for low-noise preamplifier designs.

Can MPSW45RLREG be used in linear regulator applications?

Yes, the MPSW45RLREG supports linear operation with V_CE adjustable from near-saturation to 40 V. Its low V_CE(sat) ≤ 1.5 V and high h_FE enable efficient pass-transistor implementation in adjustable LDOs or current sources, provided thermal limits (R_θJA = 125°C/W) are respected.

MPSW45RLREG Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 Long Body, Formed Leads

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN - Darlington

Current - Collector (Ic) (Max):: 1 A

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 1.5V @ 2mA, 1A

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 25000 @ 200mA, 5V

Power - Max:: 1 W

Frequency - Transition:: 100MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92 (TO-226)

MPSW45RLREG FAQ

1.How can I place an order for MPSW45RLREG through Aetrix?

Please submit a Request for Quotation (RFQ) for MPSW45RLREG 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 MPSW45RLREG reliable?

The price and inventory of MPSW45RLREG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPSW45RLREG is usually 5 days.

3.What payment methods are accepted for MPSW45RLREG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPSW45RLREG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPSW45RLREG?

MPSW45RLREG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPSW45RLREG 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 MPSW45RLREG?

For technical support, including MPSW45RLREG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPSW45RLREG requirements.

6.How does Aetrix verify that MPSW45RLREG is sourced from the original manufacturer or authorized distributors?

All MPSW45RLREG 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 MPSW45RLREG meets industry standards.

7.What is the process for return or replacement of MPSW45RLREG?

All MPSW45RLREG units undergo pre-shipment inspection (PSI). If there is an issue with MPSW45RLREG, 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 MPSW45RLREG part is unused and in its original packaging.

Return procedure for MPSW45RLREG:

1.Submit a request within 90 days.

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

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