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

onsemi MPSA42_D26Z

Name: MPSA42_D26Z
Brand: onsemi
SKU: MPSA42_D26Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MPSA42_D26Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: MPSA42_D26Z.pdf

Description:: TRANS NPN 300V 0.5A TO-92-3

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Product details

Overview

MPSA42_D26Z from Fairchild Semiconductor is an NPN high-voltage bipolar junction transistor designed for video output stage amplification in color CRT systems and other high-voltage switching or linear amplifier applications. It features 300 V collector-emitter and collector-base breakdown voltage, 500 mA continuous collector current, and operates across –55 °C to +150 °C junction temperature range.

For engineers reviewing the MPSA42_D26Z datasheet, pinout, applications, or equivalent options, this part serves as a TO-92 packaged high-voltage NPN amplifier with verified DC current gain (h_FE ≥ 25 at I_C = 1 mA), low saturation voltage (V_CE(sat) ≤ 0.5 V), and 50 MHz f_T, suitable for legacy display driver and HV bias supply designs.

Technical Context

The MPSA42_D26Z implements a planar epitaxial NPN structure optimized for high-voltage operation up to 300 V, with process-specific doping profiles enabling stable gain and leakage performance at elevated V_CB. Its thermal resistance (R_θJA = 200 °C/W on FR-4) and 625 mW power dissipation support moderate-duty-cycle video sweep and flyback auxiliary drive functions.

It delivers h_FE of 25–140 across I_C = 0.1–100 mA and maintains V_(BR)CEO ≥ 300 V under I_C = 1 mA test conditions. The device exhibits C_cb = 3.0 pF at V_CB = 20 V and f = 1 MHz, supporting bandwidth-limited high-voltage signal amplification without parasitic resonance in CRT deflection circuits.

Key Specifications

Parameter	Value and Actual Design Meaning
V_(BR)CEO	300 V - Withstands 300 V collector-emitter voltage before breakdown, enabling direct drive of CRT anode supplies and HV bias rails.
I_C (continuous)	500 mA - Supports peak video output currents up to 500 mA without thermal runaway under proper heatsinking.
h_FE @ I_C = 1 mA	≥25 - Provides sufficient DC gain for low-current base drive in high-impedance video amplifier stages.
V_CE(sat) @ I_C = 20 mA	≤0.5 V - Ensures minimal conduction loss and efficient switching in HV switch-mode auxiliary supplies.
f_T	50 MHz - Enables stable small-signal amplification up to 50 MHz, covering horizontal deflection frequency harmonics.
R_θJA	200 °C/W - Specifies thermal rise per watt on standard FR-4 PCB; requires layout-aware copper pour for sustained 625 mW operation.
C_cb	3.0 pF @ V_CB = 20 V - Low collector-base capacitance minimizes Miller effect distortion in high-gain HV amplifier configurations.

Pinout & Package

Package: TO-92 (standard straight-lead configuration, EOL code D26Z denotes tape-and-reel packaging). Device marked with standard Fairchild orientation: flat side facing viewer, leads down, left-to-right = Emitter–Base–Collector.

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal	Reference node for base drive; connected to ground or low-side return in common-emitter video output stages.
Base (B)	Control input	Receives current-limited drive signal; requires series resistor to limit I_B and ensure h_FE-based I_C control.
Collector (C)	High-voltage output node	Connected to CRT anode supply or HV load; must withstand up to 300 V transient and steady-state stress.

Key Features

Feature	Design Value
High-voltage blocking capability	300 V V_CES/V_CBO enables direct interface with CRT anode supplies and HV flyback windings without external snubbing.
Wide operating temperature range	–55 °C to +150 °C junction rating supports deployment in uncooled display enclosures and industrial HV modules.
Low collector cutoff current	I_CBO ≤ 0.1 µA at V_CB = 200 V ensures minimal leakage-induced drift in precision HV bias networks.
Stable DC current gain profile	h_FE remains ≥40 at I_C = 10 mA and ≥40 at I_C = 30 mA, supporting consistent gain across video signal amplitude range.
TO-92 mechanical compatibility	Standard 3-lead through-hole package allows drop-in replacement in legacy CRT service and repair boards.

Applications

Color CRT Video Output Stage	High-Voltage Bias Supply Switch
Use Scenario: Amplifying composite video signals to drive the final cathode-grid stage of analog color CRT monitors. IC Role / Device Role / Timing Role: NPN high-voltage amplifier operating in Class-A or Class-AB mode, sourcing current into CRT cathode load. Use Value: 300 V V_(BR)CEO and 50 MHz f_T enable full-bandwidth video signal reproduction without clipping or phase distortion.	Use Scenario: Switching auxiliary HV rails in flyback-derived power supplies for CRT heater and focus circuits. IC Role / Device Role / Timing Role: High-voltage saturated switch controlling current flow through HV winding secondary outputs. Use Value: V_CE(sat) ≤ 0.5 V at I_C = 20 mA minimizes conduction loss and thermal stress during repetitive on/off cycling.
Oscilloscope Vertical Deflection Amplifier	Legacy Industrial HV Signal Generator
Use Scenario: Linear amplification of calibrated vertical position signals in analog oscilloscope mainframe designs. IC Role / Device Role / Timing Role: High-slew-rate NPN emitter-follower or common-emitter stage delivering low-distortion HV output. Use Value: Low C_cb = 3.0 pF and stable h_FE across temperature reduce gain peaking and maintain fidelity up to 20 MHz.	Use Scenario: Generating programmable HV bias for vacuum tube tester circuits and electrostatic measurement fixtures. IC Role / Device Role / Timing Role: Precision-controlled HV current source using base current feedback and emitter degeneration. Use Value: I_CBO ≤ 0.1 µA and TJ range up to +150 °C ensure long-term calibration stability in benchtop HV instruments.

Color CRT Video Output Stage

High-Voltage Bias Supply Switch

Use Scenario: Amplifying composite video signals to drive the final cathode-grid stage of analog color CRT monitors.

IC Role / Device Role / Timing Role: NPN high-voltage amplifier operating in Class-A or Class-AB mode, sourcing current into CRT cathode load.

Use Value: 300 V V_(BR)CEO and 50 MHz f_T enable full-bandwidth video signal reproduction without clipping or phase distortion.

Use Scenario: Switching auxiliary HV rails in flyback-derived power supplies for CRT heater and focus circuits.

IC Role / Device Role / Timing Role: High-voltage saturated switch controlling current flow through HV winding secondary outputs.

Use Value: V_CE(sat) ≤ 0.5 V at I_C = 20 mA minimizes conduction loss and thermal stress during repetitive on/off cycling.

Oscilloscope Vertical Deflection Amplifier

Legacy Industrial HV Signal Generator

Use Scenario: Linear amplification of calibrated vertical position signals in analog oscilloscope mainframe designs.

IC Role / Device Role / Timing Role: High-slew-rate NPN emitter-follower or common-emitter stage delivering low-distortion HV output.

Use Value: Low C_cb = 3.0 pF and stable h_FE across temperature reduce gain peaking and maintain fidelity up to 20 MHz.

Use Scenario: Generating programmable HV bias for vacuum tube tester circuits and electrostatic measurement fixtures.

IC Role / Device Role / Timing Role: Precision-controlled HV current source using base current feedback and emitter degeneration.

Use Value: I_CBO ≤ 0.1 µA and TJ range up to +150 °C ensure long-term calibration stability in benchtop HV instruments.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBTA42	SOT-23 surface-mount package; lower P_D = 350 mW; R_θJA = 357 °C/W; same V_(BR)CEO = 300 V and h_FE specs.	Designed for space-constrained PCBs where TO-92 footprint is unavailable; unsuitable for >200 mW continuous dissipation.	Select MMBTA42 only when board area is critical and thermal management permits lower power operation.
PZTA42	SOT-223 package with exposed collector tab; P_D = 1,000 mW; R_θJA = 125 °C/W; identical electrical ratings but enhanced thermal performance.	Supports higher continuous power in compact form factor; requires solder pad thermal relief design for optimal heat transfer.	Choose PZTA42 when >625 mW average dissipation or improved thermal reliability is required in SMT layouts.

Compared with MPSA42_D26Z, MMBTA42 trades package size for reduced thermal capability, while PZTA42 retains identical electrical behavior but delivers 1.6× higher power dissipation via its thermally enhanced SOT-223 construction-making it suitable for upgraded reliability in HV industrial controls.

Availability

MPSA42_D26Z is available at Aetrix Electronics and suitable for CRT video output stages, high-voltage bias supply switching, and legacy oscilloscope vertical amplifier circuits requiring stable component supply and long-lifecycle support.

Supply support for MPSA42_D26Z 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

Fairchild Semiconductor was a U.S.-based semiconductor manufacturer specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016; its legacy product lines remain widely supported in industrial and legacy electronics.

The MPSA42_D26Z belongs to Fairchild's general-purpose high-voltage transistor family, engineered specifically for analog video, CRT, and HV power supply applications where robustness, predictable gain, and high breakdown voltage are essential.

FAQ

What is the maximum collector-emitter voltage rating for MPSA42_D26Z?

The MPSA42_D26Z has a guaranteed minimum collector-emitter breakdown voltage V_(BR)CEO of 300 V at I_C = 1.0 mA and T_A = 25 °C. This rating is maintained across its full operating temperature range and forms the basis for its use in CRT anode drive and HV bias circuits. The MPSA42_D26Z must not be operated above this voltage in any condition without external clamping.

Does MPSA42_D26Z support surface-mount assembly?

No, MPSA42_D26Z is supplied in the through-hole TO-92 package with straight leads and EOL code D26Z indicating tape-and-reel packaging for automated insertion. For surface-mount alternatives, consider the MMBTA42 (SOT-23) or PZTA42 (SOT-223), which share identical electrical specifications but differ in thermal and mechanical implementation. The MPSA42_D26Z itself is not compatible with reflow or wave soldering processes.

What is the DC current gain (h_FE) range of MPSA42_D26Z at typical operating conditions?

The MPSA42_D26Z exhibits h_FE ≥ 25 at I_C = 1.0 mA and V_CE = 10 V, ≥40 at I_C = 10 mA, and ≥40 at I_C = 30 mA-all tested at T_A = 25 °C. Gain remains functional across –40 °C to +125 °C, though values decrease at temperature extremes. This h_FE profile ensures reliable base drive sizing in MPSA42_D26Z-based video amplifier designs.

Can MPSA42_D26Z be used in switching applications?

Yes, the MPSA42_D26Z is suitable for medium-speed switching applications such as HV bias supply control, provided V_CE(sat) ≤ 0.5 V at I_C = 20 mA and switching frequencies remain below 1 MHz. Its 50 MHz f_T and low C_cb = 3.0 pF support clean turn-on/turn-off edges, but it is not optimized for high-frequency SMPS. For fast-switching use, verify gate/base drive strength and thermal limits in each MPSA42_D26Z implementation.

What is the thermal resistance (R_θJA) of MPSA42_D26Z on standard PCB?

The MPSA42_D26Z has a specified R_θJA of 200 °C/W when mounted on a standard FR-4 PCB measuring 1.6″ × 1.6″ × 0.06″. This value assumes no additional copper pour or heatsinking. To sustain its full 625 mW power dissipation, board layout must include adequate thermal relief-such as extended copper traces or thermal vias-to prevent junction temperatures exceeding +150 °C. Derating is required above 25 °C ambient.

MPSA42_D26Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Tape & Reel (TR)

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:: 625 mW

Frequency - Transition:: 50MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

MPSA42_D26Z FAQ

1.How can I place an order for MPSA42_D26Z through Aetrix?

Please submit a Request for Quotation (RFQ) for MPSA42_D26Z 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 MPSA42_D26Z reliable?

The price and inventory of MPSA42_D26Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPSA42_D26Z is usually 5 days.

3.What payment methods are accepted for MPSA42_D26Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPSA42_D26Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPSA42_D26Z?

MPSA42_D26Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPSA42_D26Z 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 MPSA42_D26Z?

For technical support, including MPSA42_D26Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPSA42_D26Z requirements.

6.How does Aetrix verify that MPSA42_D26Z is sourced from the original manufacturer or authorized distributors?

All MPSA42_D26Z 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 MPSA42_D26Z meets industry standards.

7.What is the process for return or replacement of MPSA42_D26Z?

All MPSA42_D26Z units undergo pre-shipment inspection (PSI). If there is an issue with MPSA42_D26Z, 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 MPSA42_D26Z part is unused and in its original packaging.

Return procedure for MPSA42_D26Z:

1.Submit a request within 90 days.

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

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