Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

onsemi MPSA42_J22Z

Name: MPSA42_J22Z
Brand: onsemi
SKU: MPSA42_J22Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: MPSA42_J22Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: MPSA42_J22Z.pdf

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

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:6,995

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

MPSA42_J22Z from Fairchild Semiconductor is an NPN high-voltage amplifier transistor designed for video output stages driving color CRTs and other high-voltage analog circuits. 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_J22Z datasheet, pinout, applications, or equivalent options, this part supports high-voltage switching and linear amplification in legacy display, flyback, and pulse generator designs where robustness at >200 V bias is required.

Technical Context

The MPSA42_J22Z employs a high-voltage bipolar process (Process 48) optimized for stable gain and low leakage under sustained reverse-biased conditions. Its 300 V V_(BR)CEO and V_(BR)CBO ratings enable direct use in CRT anode supply regulation and horizontal deflection stage switching.

DC current gain (h_FE) ranges from 25 at 1 mA to 40 at 10–30 mA, supporting both small-signal amplification and medium-power switching. Saturation voltages - V_CE(sat) = 0.5 V and V_BE(sat) = 0.9 V at I_C = 20 mA / I_B = 2 mA - ensure predictable turn-on behavior in grounded-emitter configurations.

Key Specifications

Parameter	Value and Actual Design Meaning
V_(BR)CEO	300 V - Supports operation in CRT anode supplies and flyback transformer primary drive without external snubbing.
I_C (continuous)	500 mA - Enables direct drive of moderate-current high-voltage loads such as deflection yoke windings.
h_FE @ 10 mA	40 - Provides sufficient current gain for single-stage video output amplification with minimal base drive overhead.
V_CE(sat)	0.5 V @ I_C = 20 mA - Limits conduction loss in saturated-switching applications like pulse generators.
T_J range	–55°C to +150°C - Ensures reliability in thermally demanding environments including enclosed CRT chassis and industrial HV modules.
f_T	50 MHz @ I_C = 10 mA - Sufficient bandwidth for composite video signal amplification up to ~5 MHz with margin.
C_cb	3.0 pF @ V_CB = 20 V - Low Miller capacitance minimizes high-frequency instability in common-emitter amplifier configurations.

Pinout & Package

Package: TO-92 (standard radial leaded plastic package per JEDEC TO-92 outline). Pin identification follows standard emitter-base-collector (E-B-C) sequence when viewing flat side with leads down and left-to-right orientation.

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal	Connected to ground or low-impedance return path; critical for thermal stability in high-voltage common-emitter topologies.
Base (B)	Control input	Receives forward-biased drive; requires current-limiting resistor due to V_BE(sat) = 0.9 V and h_FE-dependent base current demand.
Collector (C)	High-voltage output node	Handles up to 300 V reverse bias; must be routed with adequate creepage/clearance (>3 mm) on PCB for safety compliance.

Key Features

Feature	Design Value
High breakdown voltage	300 V V_CEO/V_CBO enables direct integration into CRT anode regulation and HV pulse generation without cascading transistors.
Low collector cutoff current	I_CBO ≤ 0.1 µA @ V_CB = 200 V ensures minimal leakage-induced drift in precision HV bias networks.
Thermal robustness	R_θJA = 200 °C/W on FR-4 allows 625 mW dissipation at ambient ≤ 50°C - suitable for non-heatsinked video output stages.
Process-optimized linearity	Stable h_FE vs. I_C and low V_CE(sat) variation support consistent gain in analog video amplifiers over temperature.

Applications

Color CRT Video Output	Flyback Transformer Drive
Use Scenario: Amplifying composite video signals to drive the final cathode grid in color CRT monitors. IC Role / Device Role / Timing Role: NPN high-voltage amplifier operating in Class-A/AB linear mode with 300 V headroom. Use Value: Maintains signal fidelity up to 5 MHz while sustaining 250–300 V DC anode supply coupling without breakdown or gain collapse.	Use Scenario: Switching primary current in flyback converters used for CRT high-voltage generation. IC Role / Device Role / Timing Role: High-voltage switch controlling energy transfer to the flyback transformer primary winding. Use Value: Withstands 300 V off-state voltage and delivers 500 mA peak current during duty-cycle-limited switching, minimizing need for clamping diodes.
Pulse Generator Circuits	Industrial HV Bias Supplies
Use Scenario: Generating sharp-edged high-voltage pulses for oscilloscope timebase circuits or test equipment. IC Role / Device Role / Timing Role: Fast-switching NPN transistor in grounded-emitter configuration with controlled rise/fall times. Use Value: 50 MHz f_T and 3.0 pF C_cb support clean 100 ns pulse edges at 300 V amplitude without excessive ringing.	Use Scenario: Regulating stable high-voltage DC outputs (e.g., 150–250 V) for photomultiplier tubes or electrostatic precipitators. IC Role / Device Role / Timing Role: Series-pass element in linear HV regulator topology with feedback-controlled base drive. Use Value: Low I_CBO and wide T_J range ensure long-term stability and minimal drift under continuous 200+ V bias conditions.

Color CRT Video Output

Flyback Transformer Drive

Use Scenario: Amplifying composite video signals to drive the final cathode grid in color CRT monitors.

IC Role / Device Role / Timing Role: NPN high-voltage amplifier operating in Class-A/AB linear mode with 300 V headroom.

Use Value: Maintains signal fidelity up to 5 MHz while sustaining 250–300 V DC anode supply coupling without breakdown or gain collapse.

Use Scenario: Switching primary current in flyback converters used for CRT high-voltage generation.

IC Role / Device Role / Timing Role: High-voltage switch controlling energy transfer to the flyback transformer primary winding.

Use Value: Withstands 300 V off-state voltage and delivers 500 mA peak current during duty-cycle-limited switching, minimizing need for clamping diodes.

Pulse Generator Circuits

Industrial HV Bias Supplies

Use Scenario: Generating sharp-edged high-voltage pulses for oscilloscope timebase circuits or test equipment.

IC Role / Device Role / Timing Role: Fast-switching NPN transistor in grounded-emitter configuration with controlled rise/fall times.

Use Value: 50 MHz f_T and 3.0 pF C_cb support clean 100 ns pulse edges at 300 V amplitude without excessive ringing.

Use Scenario: Regulating stable high-voltage DC outputs (e.g., 150–250 V) for photomultiplier tubes or electrostatic precipitators.

IC Role / Device Role / Timing Role: Series-pass element in linear HV regulator topology with feedback-controlled base drive.

Use Value: Low I_CBO and wide T_J range ensure long-term stability and minimal drift under continuous 200+ V bias conditions.

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; same 300 V V_(BR)CEO, but lower P_D (350 mW) and higher R_θJA (357 °C/W).	Preferred for space-constrained PCBs; unsuitable for >200 mW continuous dissipation without thermal relief.	Select MMBTA42 only when board area is limited and power dissipation remains below 150 mW.
PZTA42	SOT-223 package with exposed collector tab; rated for 1 W P_D and R_θJA = 125 °C/W on specified PCB pad.	Required for >500 mW average power or forced-air-cooled HV stages; larger footprint than TO-92.	Choose PZTA42 when thermal management demands >625 mW capability or improved long-term reliability under sustained load.

Compared with MMBTA42, MPSA42_J22Z offers higher power handling and simpler through-hole assembly; versus PZTA42, it trades thermal performance for compactness and legacy compatibility in CRT service replacements.

Availability

MPSA42_J22Z is available at Aetrix Electronics and suitable for CRT video output stages, flyback converter primary switches, and industrial high-voltage bias supplies requiring stable component supply across extended product lifecycles.

Supply support for MPSA42_J22Z 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.

The MPSA42_J22Z belongs to Fairchild's legacy high-voltage bipolar transistor family, engineered specifically for analog video, CRT, and pulse-generation applications demanding rugged 300 V operation and stable gain at elevated temperatures.

FAQ

What is the maximum collector-emitter voltage rating for MPSA42_J22Z?

The MPSA42_J22Z has a guaranteed minimum V_(BR)CEO of 300 V at I_C = 1.0 mA and T_A = 25°C. This rating is validated per Fairchild's absolute maximum specifications and applies to continuous DC operation. Derating is required above 25°C ambient, and pulsed operation beyond steady-state limits requires factory consultation per datasheet Note 2.

Is MPSA42_J22Z compatible with TO-92 socket footprints used for general-purpose transistors?

Yes, MPSA42_J22Z uses the standard TO-92 package with E-B-C pinout (flat side facing viewer, leads down, left-to-right = emitter-base-collector). It fits mechanically and electrically into common TO-92 sockets and PCB footprints designed for 2N3904, BC547, or similar through-hole NPN transistors, though its 300 V rating and higher power dissipation require appropriate layout clearance.

Does MPSA42_J22Z have a documented SPICE model for circuit simulation?

Yes, the official Fairchild datasheet for MPSA42_J22Z includes a verified SPICE model with parameters including Is = 34.9 fA, Bf = 2650, Vaf = 100 V, and Cjc = 14.23 pF. This model accurately reproduces DC gain, saturation behavior, capacitance, and frequency response for design validation in tools like LTspice or PSpice.

Can MPSA42_J22Z replace MPSA92 in high-voltage amplifier circuits?

No - MPSA42_J22Z is an NPN transistor, while MPSA92 is a PNP device with complementary polarity and identical 300 V ratings. Direct replacement would invert signal phase and require circuit rework. They are functional complements, not drop-in substitutes; use only if redesigning biasing and signal path polarity.

What is the thermal resistance from junction to ambient for MPSA42_J22Z on a standard FR-4 PCB?

The datasheet specifies R_θJA = 200 °C/W for MPSA42_J22Z mounted on a 1.6" × 1.6" × 0.06" FR-4 board. This value assumes no copper pour or thermal vias. Adding a 1 cm² copper pad connected to the collector lead reduces effective R_θJA by ~25%, improving safe operating area for continuous 500 mW operation.

MPSA42_J22Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

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:: 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_J22Z FAQ

1.How can I place an order for MPSA42_J22Z through Aetrix?

Please submit a Request for Quotation (RFQ) for MPSA42_J22Z 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_J22Z reliable?

The price and inventory of MPSA42_J22Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPSA42_J22Z is usually 5 days.

3.What payment methods are accepted for MPSA42_J22Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPSA42_J22Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPSA42_J22Z?

MPSA42_J22Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPSA42_J22Z 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_J22Z?

For technical support, including MPSA42_J22Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPSA42_J22Z requirements.

6.How does Aetrix verify that MPSA42_J22Z is sourced from the original manufacturer or authorized distributors?

All MPSA42_J22Z 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_J22Z meets industry standards.

7.What is the process for return or replacement of MPSA42_J22Z?

All MPSA42_J22Z units undergo pre-shipment inspection (PSI). If there is an issue with MPSA42_J22Z, 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_J22Z part is unused and in its original packaging.

Return procedure for MPSA42_J22Z:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…