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

onsemi KSA1142OSTU

Name: KSA1142OSTU
Brand: onsemi
SKU: KSA1142OSTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSA1142OSTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KSA1142OSTU.pdf

Description:: TRANS PNP 180V 0.1A TO-126-3

Quantity:: RFQ Add To RFQ list

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Inventory:1,544

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Product details

Overview

KSA1142OSTU from onsemi is a PNP epitaxial silicon transistor rated for -180 V V_CEO, -100 mA I_C, and 8 W P_C at T_C=25°C, with f_T = 180 MHz and h_FE = 100–320 (class Y). It serves as a high-voltage, medium-power audio and RF amplifier stage in discrete power amplifier designs.

For engineers reviewing the KSA1142OSTU datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-126 package, complementary pairing with KSC2682, safe operating area (SOA) derating behavior, and verified performance under pulsed conditions (PW ≤ 350 µs, duty ≤ 2%).

Technical Context

The KSA1142OSTU is a discrete PNP bipolar junction transistor optimized for linear amplification in audio-frequency and high-frequency power stages. Its design emphasizes high breakdown voltage (-180 V VCBO/VCEO), low saturation voltages (V_CE(sat) = -0.16 V typ. at I_C = -50 mA, I_B = -5 mA), and wide SOA coverage up to 10 ms pulse width.

It operates with DC current gain h_FE ranging from 100–200 (class O) or 160–320 (class Y), depending on I_C and V_CE; noise figure is specified at 4 dB (R_S = 10 kΩ, f = 1 MHz), supporting low-noise preamplifier use in analog signal chains.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-180 V - supports high-voltage rail operation in Class-AB audio output stages without breakdown risk
I_C	-100 mA - enables medium-current drive capability for driver or output stage in discrete amplifiers
f_T	180 MHz - ensures stable gain up to VHF band, suitable for HF power amplifier applications
V_CE(sat)	-0.16 V (typ.) at I_C = -50 mA - minimizes conduction loss and thermal stress in saturated switching or linear operation
h_FE	100–320 (class Y) - provides predictable bias stability across production lots for fixed-bias or emitter-degenerated designs
P_C (T_C=25°C)	8 W - allows high-power dissipation with heatsink mounting, critical for continuous-duty amplifier output devices
C_ob	4.5–7 pF - limits Miller capacitance impact on high-frequency stability in common-emitter configurations

Pinout & Package

Package: TO-126 (standard outline per MKT-TO126AArev2), thermally enhanced plastic case with metal tab for heatsink attachment. Terminal length D = 3.45–4.05 mm, E = 6.45–7.45 mm (TSSTU variant).

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to most negative supply node; requires low-impedance return path for stable bias
2 (Collector)	Current source terminal	Mounted to heatsink via metal tab; electrically isolated from tab per TO-126 mechanical spec
3 (Base)	Control input	Drives transistor into active/saturation; requires current-limiting resistor to prevent overdrive

Key Features

Feature	Design Value
High V_CEO rating	Supports ±150 V supply rails in push-pull amplifier topologies without secondary breakdown
Low V_CE(sat)	Reduces power loss and thermal rise in Class-A/AB output stages, improving efficiency and reliability
Class Y h_FE binning	Ensures consistent DC bias point across units, simplifying production calibration of discrete amplifier modules
180 MHz f_T	Enables stable small-signal gain up to 30 MHz, meeting requirements for HF communication transmitter drivers
SOA compliance (10 ms)	Validated safe operation under transient overload, critical for protection against speaker short-circuit events

Applications

Audio Power Amplifier	RF Driver Stage
Use Scenario: Discrete Class-AB output stage in Hi-Fi receiver power amplifiers delivering 20–50 W into 4–8 Ω loads. IC Role / Device Role / Timing Role: PNP complement to NPN KSC2682 in push-pull output pair; handles negative half-cycle current delivery. Use Value: High V_CEO and SOA robustness prevent latch-up during clipping or reactive load transients.	Use Scenario: Final driver stage in 27 MHz CB radio transmitter, preceding MOSFET final amplifier. IC Role / Device Role / Timing Role: Linear RF power amplifier biased in Class-A for low-distortion signal amplification before modulation. Use Value: 180 MHz f_T and low C_ob ensure flat gain response and minimal phase shift across HF band.
High-Voltage Signal Generator	Industrial Relay Driver
Use Scenario: Output buffer in programmable AC source generating ±100 V sine waves at 1 kHz–20 kHz. IC Role / Device Role / Timing Role: Medium-power linear amplifier driving transformer-coupled output; operates in active region with precision bias. Use Value: Low noise figure (4 dB) preserves signal integrity in low-level waveform synthesis paths.	Use Scenario: Solid-state replacement for electromechanical relay in PLC output module switching 120 VAC/1 A loads. IC Role / Device Role / Timing Role: Saturated switch controlling gate of external MOSFET or directly driving relay coil with flyback protection. Use Value: -0.16 V V_CE(sat) minimizes heat generation during continuous ON state, extending system MTBF.

Audio Power Amplifier

RF Driver Stage

Use Scenario: Discrete Class-AB output stage in Hi-Fi receiver power amplifiers delivering 20–50 W into 4–8 Ω loads.

IC Role / Device Role / Timing Role: PNP complement to NPN KSC2682 in push-pull output pair; handles negative half-cycle current delivery.

Use Value: High V_CEO and SOA robustness prevent latch-up during clipping or reactive load transients.

Use Scenario: Final driver stage in 27 MHz CB radio transmitter, preceding MOSFET final amplifier.

IC Role / Device Role / Timing Role: Linear RF power amplifier biased in Class-A for low-distortion signal amplification before modulation.

Use Value: 180 MHz f_T and low C_ob ensure flat gain response and minimal phase shift across HF band.

High-Voltage Signal Generator

Industrial Relay Driver

Use Scenario: Output buffer in programmable AC source generating ±100 V sine waves at 1 kHz–20 kHz.

IC Role / Device Role / Timing Role: Medium-power linear amplifier driving transformer-coupled output; operates in active region with precision bias.

Use Value: Low noise figure (4 dB) preserves signal integrity in low-level waveform synthesis paths.

Use Scenario: Solid-state replacement for electromechanical relay in PLC output module switching 120 VAC/1 A loads.

IC Role / Device Role / Timing Role: Saturated switch controlling gate of external MOSFET or directly driving relay coil with flyback protection.

Use Value: -0.16 V V_CE(sat) minimizes heat generation during continuous ON state, extending system MTBF.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP high-voltage power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
KSA992FBU	V_CEO = -160 V, h_FE = 120–240, TO-92 package (lower power, no heatsink mount)	Limited to low-power preamp or switching roles; unsuitable for >1 W continuous dissipation	Select when board space is constrained and thermal load is <0.5 W; not a drop-in replacement
MJD44H11G	V_CEO = -100 V, I_C = -8 A, TO-220 package, higher current but lower voltage rating	Better suited for low-voltage, high-current motor control; insufficient for ±100 V rail systems	Choose for industrial DC load switching where voltage stress is <80 V; requires PCB layout change

Compared with KSA1142OSTU, KSA992FBU trades voltage headroom and thermal capability for compactness, while MJD44H11G sacrifices breakdown margin for current drive-neither matches the original's balanced high-voltage, medium-current, and SOA-optimized profile.

Availability

KSA1142OSTU is available at Aetrix Electronics and suitable for audio power amplifiers, RF driver stages, high-voltage signal generators, and industrial relay drivers requiring stable component supply despite end-of-life status.

Supply support for KSA1142OSTU 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 Fairchild Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics, with leadership in power management, analog, sensors, and discrete devices.

The KSA1142OSTU belongs to onsemi's legacy high-voltage bipolar transistor family, designed specifically for robust, linear amplification in professional audio and industrial signal conditioning equipment.

FAQ

Is KSA1142OSTU still in production?

No, KSA1142OSTU is discontinued and not recommended for new designs per onsemi's official documentation (Rev. 1, May 2024). However, Aetrix Electronics maintains limited legacy inventory with full traceability and offers lifecycle coordination support for ongoing production programs relying on KSA1142OSTU.

What is the pin configuration of KSA1142OSTU?

KSA1142OSTU uses a TO-126 package with pinout: Pin 1 = Emitter, Pin 2 = Collector (tab-connected, electrically isolated), Pin 3 = Base. This configuration is confirmed in the official onsemi datasheet diagram and mechanical drawing MKT-TO126AArev2.

How does KSA1142OSTU compare to its NPN complement KSC2682?

KSA1142OSTU is the designated PNP complement to the NPN KSC2682, sharing matched V_CEO (-180 V), similar f_T (180 MHz vs. 170 MHz), and compatible TO-126 packaging. Their h_FE ranges and saturation characteristics are engineered for symmetrical push-pull performance in Class-AB amplifiers.

Can KSA1142OSTU be used in switching applications?

Yes, KSA1142OSTU supports switching use with verified V_CE(sat) = -0.16 V (typ.) at I_C = -50 mA and I_B = -5 mA, but its primary qualification is for linear amplification. For high-frequency switching, verify SOA boundaries and thermal management-pulse testing confirms safe operation up to 350 µs PW and 2% duty cycle.

What thermal derating applies to KSA1142OSTU?

KSA1142OSTU's power dissipation must be derated linearly above T_C = 25°C: from 8 W at 25°C to 0 W at T_C = 150°C, per Figure 8 in the datasheet. The device's maximum junction temperature is 150°C, and case-to-heatsink thermal resistance must be minimized using appropriate mounting hardware and thermal interface material.

KSA1142OSTU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 100 mA

Voltage - Collector Emitter Breakdown (Max):: 180 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 5mA, 50mA

Current - Collector Cutoff (Max):: 1µA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 10mA, 5V

Power - Max:: 1.2 W

Frequency - Transition:: 180MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126-3

KSA1142OSTU FAQ

1.How can I place an order for KSA1142OSTU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSA1142OSTU 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 KSA1142OSTU reliable?

The price and inventory of KSA1142OSTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSA1142OSTU is usually 5 days.

3.What payment methods are accepted for KSA1142OSTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSA1142OSTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSA1142OSTU?

KSA1142OSTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSA1142OSTU 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 KSA1142OSTU?

For technical support, including KSA1142OSTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSA1142OSTU requirements.

6.How does Aetrix verify that KSA1142OSTU is sourced from the original manufacturer or authorized distributors?

All KSA1142OSTU 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 KSA1142OSTU meets industry standards.

7.What is the process for return or replacement of KSA1142OSTU?

All KSA1142OSTU units undergo pre-shipment inspection (PSI). If there is an issue with KSA1142OSTU, 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 KSA1142OSTU part is unused and in its original packaging.

Return procedure for KSA1142OSTU:

1.Submit a request within 90 days.

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

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