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

onsemi MPSW42

Name: MPSW42
Brand: onsemi
SKU: MPSW42
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MPSW42

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: MPSW42.pdf

Description:: TRANS NPN 300V 0.5A TO92

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MPSW42 from onsemi is an NPN silicon high-voltage transistor rated for 300 V_CEO, 500 mA continuous collector current, and 1.0 W dissipation at T_A = 25°C, designed for switching and linear amplification in high-voltage industrial power supplies and relay drivers.

For engineers reviewing the MPSW42 datasheet, pinout, applications, or equivalent options, key selection considerations include its 300 V breakdown rating, TO-92 package thermal resistance (R_JA = 125 °C/W), DC current gain range (h_FE = 25–40 at I_C = 1–30 mA), and saturation voltage performance (V_CE(sat) ≤ 0.5 V at I_C/I_B = 10).

Technical Context

The MPSW42 operates as a general-purpose NPN bipolar junction transistor with fixed-emitter configuration, optimized for high-voltage switching where robust V_CEO and V_CBO ratings (both 300 V) prevent avalanche failure under transient overvoltage. Its f_T of 50 MHz supports moderate-speed switching up to ~100 kHz in hard-switched topologies.

Thermal design relies on its R_JC = 50 °C/W and R_JA = 125 °C/W values, requiring heatsinking only when operating near P_D = 2.5 W at T_C = 25°C. Cutoff currents (I_CBO, I_EBO ≤ 0.1 A) confirm stable off-state blocking across −55°C to +150°C junction temperature range.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	300 Vdc - Withstands 300 V between collector and emitter before breakdown, enabling use in 240 VAC line-derived circuits with safety margin.
I_C (continuous)	500 mAdc - Supports load switching up to 0.5 A DC without derating at 25°C ambient.
P_D @ T_A = 25°C	1.0 W - Maximum power dissipation without heatsink at room temperature; derates 8 mW/°C above 25°C.
h_FE	25–40 - DC current gain sufficient for low-gain driver stages; requires ≥2.0 mA base drive for 20 mA collector output.
V_CE(sat)	≤ 0.5 Vdc at I_C = 20 mAdc, I_B = 2.0 mAdc - Ensures <10 mW saturation loss at 20 mA, minimizing heat in switching mode.
f_T	50 MHz - Enables reliable operation in audio-frequency and low-MHz signal amplification or PWM control feedback paths.
R_JA	125 °C/W - Junction-to-ambient thermal resistance defines required PCB copper area or heatsink for thermal management.

Pinout & Package

Package: TO-92 (Case 29-10), 1 W power rating, Pb-free (MPSW42RLRAG variant), through-hole mounting.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Reference terminal for base-emitter junction; connects to ground or low-side return path in common-emitter configurations.
2	Base	Control input; requires current-limited drive (e.g., 2.0 mA for 20 mA I_C) to achieve specified V_CE(sat).
3	Collector	High-side output node; handles up to 300 V and 500 mA, routed to load or supply rail in switching applications.

Key Features

Feature	Design Value
High-voltage capability	300 V_CEO/V_CBO enables direct interface with 240 VAC rectified rails without external snubbers.
Low saturation voltage	V_CE(sat) ≤ 0.5 V reduces conduction loss and self-heating in repetitive switching duty cycles.
Wide temperature range	−55°C to +150°C operating junction range supports deployment in automotive engine compartments and industrial enclosures.
Pb-free packaging	MPSW42RLRAG complies with RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level 1.
TO-92 mechanical standardization	Compatible with legacy through-hole assembly lines and manual prototyping; footprint matches industry-standard Case 29-10.

Applications

Industrial Power Supply Control	AC Line Voltage Monitoring
Use Scenario: Switching control of auxiliary 12 V bias supplies derived from 240 VAC mains via transformerless capacitive dropper networks. IC Role / Device Role / Timing Role: High-voltage NPN switch driving optocoupler LED or MOSFET gate in isolated feedback path. Use Value: 300 V rating eliminates need for series resistor voltage division; V_CE(sat) ≤ 0.5 V ensures minimal dropout and thermal rise at 20–50 mA loads.	Use Scenario: Overvoltage detection circuit sampling rectified AC line with resistive divider and triggering protection latch. IC Role / Device Role / Timing Role: Linear amplifier stage conditioning divided AC peak voltage for comparator input. Use Value: h_FE stability across −55°C to +150°C ensures consistent gain in unregulated environments; low C_cb (≤3.0 pF) preserves high-frequency response.
Electromechanical Relay Driver	DC Motor Commutation Snubber
Use Scenario: Driving 24 VDC coil relays in programmable logic controller (PLC) output modules with flyback suppression. IC Role / Device Role / Timing Role: Saturated switch sinking relay coil current during ON state; clamped by external diode during OFF transition. Use Value: 500 mA I_C rating supports standard 24 V/400 mW relays; TO-92 package allows dense layout in DIN-rail mounted I/O cards.	Use Scenario: Passive snubber network across brushed DC motor brushes to suppress commutation arcing and EMI. IC Role / Device Role / Timing Role: Not used as active device; instead, its parasitic capacitance (C_cb ≤ 3.0 pF) and V_CEO rating inform snubber capacitor selection. Use Value: Low C_cb minimizes unintended coupling into control logic; 300 V rating validates use with 120 VDC motor bus transients.

Industrial Power Supply Control

AC Line Voltage Monitoring

Use Scenario: Switching control of auxiliary 12 V bias supplies derived from 240 VAC mains via transformerless capacitive dropper networks.

IC Role / Device Role / Timing Role: High-voltage NPN switch driving optocoupler LED or MOSFET gate in isolated feedback path.

Use Value: 300 V rating eliminates need for series resistor voltage division; V_CE(sat) ≤ 0.5 V ensures minimal dropout and thermal rise at 20–50 mA loads.

Use Scenario: Overvoltage detection circuit sampling rectified AC line with resistive divider and triggering protection latch.

IC Role / Device Role / Timing Role: Linear amplifier stage conditioning divided AC peak voltage for comparator input.

Use Value: h_FE stability across −55°C to +150°C ensures consistent gain in unregulated environments; low C_cb (≤3.0 pF) preserves high-frequency response.

Electromechanical Relay Driver

DC Motor Commutation Snubber

Use Scenario: Driving 24 VDC coil relays in programmable logic controller (PLC) output modules with flyback suppression.

IC Role / Device Role / Timing Role: Saturated switch sinking relay coil current during ON state; clamped by external diode during OFF transition.

Use Value: 500 mA I_C rating supports standard 24 V/400 mW relays; TO-92 package allows dense layout in DIN-rail mounted I/O cards.

Use Scenario: Passive snubber network across brushed DC motor brushes to suppress commutation arcing and EMI.

IC Role / Device Role / Timing Role: Not used as active device; instead, its parasitic capacitance (C_cb ≤ 3.0 pF) and V_CEO rating inform snubber capacitor selection.

Use Value: Low C_cb minimizes unintended coupling into control logic; 300 V rating validates use with 120 VDC motor bus transients.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC639	V_CEO = 60 V, I_C = 1.0 A, h_FE = 40–250 - Lower voltage rating but higher current and gain variability.	Suitable only for sub-60 V systems; cannot replace MPSW42 in 240 VAC-derived circuits without redesign.	Select BC639 only when operating voltage ≤ 60 V and higher h_FE tolerance is needed for base-current-limited drive.
2N5551	V_CEO = 160 V, I_C = 600 mA, f_T = 100 MHz - Higher speed but insufficient for 240 VAC peak (≈340 V) applications.	Not rated for full-wave rectified 240 VAC (339 V peak); risk of avalanche failure during surge events.	Choose 2N5551 for high-speed signal switching below 160 V; avoid in mains-connected designs requiring 300 V margin.

Compared with BC639 and 2N5551, the MPSW42 uniquely balances 300 V standoff, 500 mA drive, and TO-92 compatibility-making it irreplaceable in cost-sensitive, high-voltage industrial controls where both voltage margin and package legacy matter.

Availability

MPSW42 is available at Aetrix Electronics and suitable for industrial power supply control, AC line monitoring, electromechanical relay driving, and DC motor commutation snubber applications requiring stable component supply and long-term manufacturability.

Supply support for MPSW42 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, cloud, and consumer markets.

The MPSW42 belongs to onsemi's legacy discrete transistor product line, engineered specifically for high-reliability, high-voltage switching in cost-sensitive industrial equipment where TO-92 form factor and 300 V capability are mandatory.

FAQ

What is the maximum collector-emitter voltage rating for the MPSW42?

The MPSW42 has a guaranteed minimum V_(BR)CEO of 300 Vdc at I_C = 1.0 mAdc and I_B = 0. This rating is validated per onsemi's datasheet Rev. 7 and applies to the MPSW42, MPSW42RLRA, and MPSW42RLRAG variants. Operation above this voltage risks irreversible avalanche breakdown, so derating to 240 V is recommended for reliability-critical designs using the MPSW42.

Is the MPSW42RLRAG variant RoHS-compliant?

Yes, the MPSW42RLRAG is explicitly marked as Pb-free in onsemi's ordering information and conforms to RoHS Directive 2011/65/EU. The "G" suffix denotes lead-free termination, and the device meets JEDEC J-STD-020 moisture sensitivity level 1. The MPSW42RLRAG shares identical electrical and thermal specifications with the non-Pb-free MPSW42RLRA, making it a drop-in replacement where RoHS compliance is required for the MPSW42.

What is the DC current gain (h_FE) range for the MPSW42 at different collector currents?

The MPSW42 exhibits h_FE = 25 (min) at I_C = 1.0 mAdc, h_FE = 40 (min) at I_C = 10 mAdc, and h_FE = 40 (min) at I_C = 30 mAdc-all measured at V_CE = 10 Vdc and T_A = 25°C. These values are specified in the Electrical Characteristics table of the official MPSW42 datasheet. Designers must size base resistors assuming h_FE = 25 for worst-case turn-on in critical MPSW42 applications.

Can the MPSW42 be used in surface-mount designs?

No, the MPSW42 is exclusively offered in the through-hole TO-92 (Case 29-10) package, as confirmed by onsemi's mechanical drawings and ordering information. Neither the MPSW42 nor its variants (including MPSW42RLRAG) are available in SMT packages such as SOT-23 or SC-70. For surface-mount alternatives with similar voltage rating, engineers should evaluate other onsemi families-not the MPSW42-since the MPSW42 itself is not compatible with reflow or wave soldering processes.

What is the thermal resistance from junction to case (R_JC) for the MPSW42?

The MPSW42 has a maximum thermal resistance of R_JC = 50 °C/W, as published in the Thermal Characteristics section of the official datasheet. This value assumes proper mounting to a heatsink via the collector tab (pin 3) in TO-92 configuration. When operating the MPSW42 at elevated power levels, this R_JC must be combined with heatsink R_CA to calculate total junction-to-ambient resistance-critical for ensuring T_J remains within −55°C to +150°C limits in the final MPSW42 implementation.

MPSW42 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 300 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 2mA, 20mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 30mA, 10V

Power - Max:: 1 W

Frequency - Transition:: 50MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

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

MPSW42 FAQ

1.How can I place an order for MPSW42 through Aetrix?

Please submit a Request for Quotation (RFQ) for MPSW42 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 MPSW42 reliable?

The price and inventory of MPSW42 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPSW42 is usually 5 days.

3.What payment methods are accepted for MPSW42?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPSW42 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPSW42?

MPSW42 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPSW42 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 MPSW42?

For technical support, including MPSW42 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPSW42 requirements.

6.How does Aetrix verify that MPSW42 is sourced from the original manufacturer or authorized distributors?

All MPSW42 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 MPSW42 meets industry standards.

7.What is the process for return or replacement of MPSW42?

All MPSW42 units undergo pre-shipment inspection (PSI). If there is an issue with MPSW42, 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 MPSW42 part is unused and in its original packaging.

Return procedure for MPSW42:

1.Submit a request within 90 days.

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

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