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

onsemi KSA1174FTA

Name: KSA1174FTA
Brand: onsemi
SKU: KSA1174FTA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSA1174FTA

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KSA1174FTA.pdf

Description:: TRANS PNP 120V 0.05A TO-92S

Quantity:: RFQ Add To RFQ list

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Inventory:2,079

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Product details

Overview

KSA1174FTA from ON Semiconductor (formerly Fairchild) is a PNP epitaxial silicon transistor designed for audio-frequency low-noise amplification, with V_CEO = −120 V, I_C = −50 mA, P_C = 300 mW, hFE2 = 200–400 (Class P), and f_T = 50–100 MHz - used in preamplifier stages of consumer audio equipment.

For engineers reviewing the KSA1174FTA datasheet, pinout, applications, or equivalent options, key selection criteria include low-noise performance (NV = 25–40 mV), high DC current gain at low bias (hFE ≥ 200 @ I_C = −1 mA), V_CE(sat) ≤ −0.3 V, TO-92S package compatibility, and complementary pairing with KSC2784.

Technical Context

This PNP bipolar junction transistor operates in linear amplification mode with emitter-grounded configuration. Its design emphasizes low-noise audio signal handling, supported by guaranteed hFE2 classification (P-grade: 200–400), tight V_BE(on) range (−0.55 to −0.65 V @ I_C = −1 mA), and Cob ≤ 3 pF at V_CB = −30 V.

The device features thermal derating down to zero power at 175°C ambient and is rated for junction temperatures up to 150°C. It is not intended for switching-only applications but optimized for analog gain stability across −55°C to +150°C storage and operation ranges.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−120 V - supports high-voltage audio stage biasing without breakdown
I_C	−50 mA - sets maximum continuous collector current for linear operation
P_C	300 mW - defines thermal limit at T_A = 25°C; derates linearly above 25°C
hFE2 (Class P)	200–400 - ensures predictable DC gain in low-current preamp bias points
f_T	50–100 MHz - enables stable gain up to mid-audio frequencies with margin
NV	25–40 mV - quantifies inherent input-referred noise in 1 kHz bandwidth
V_CE(sat)	≤ −0.3 V @ I_C = −10 mA, I_B = −1 mA - minimizes voltage headroom loss in emitter-follower buffers

Pinout & Package

Package: TO-92S (3-lead plastic through-hole), lead spacing 1.27 mm, body height 4.00 mm, standardized for compact audio PCB layouts.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current source terminal	Connected to circuit ground or bias rail in common-emitter amplifier configurations
2 (Collector)	Current sink terminal	Drives load or next stage; reverse-biased under normal operation
3 (Base)	Control input	Accepts small forward-biased current to modulate collector-emitter conduction

Key Features

Feature	Design Value
Low-noise audio amplification	NV = 25–40 mV enables clean signal amplification in microphone and phono preamps
High DC current gain consistency	hFE2 Class P (200–400) reduces unit-to-unit gain variation in production audio circuits
Complementary pairing	Engineered as direct PNP counterpart to NPN KSC2784 for push-pull output stages
Thermal robustness	Junction temperature rating of 150°C supports reliable operation in enclosed audio enclosures
TO-92S footprint compatibility	Standardized 3-lead through-hole package allows drop-in replacement in legacy audio designs

Applications

Microphone Preamp	Phono Stage Amplifier
Use Scenario: Amplifying weak signals from condenser microphones with minimal added noise. IC Role / Device Role / Timing Role: PNP BJT configured in common-emitter topology for high-input-impedance, low-noise voltage gain. Use Value: NV = 25–40 mV and hFE ≥ 200 ensure SNR preservation at sub-mV input levels.	Use Scenario: Boosting RIAA-equalized signals from magnetic phono cartridges before line-level processing. IC Role / Device Role / Timing Role: First-stage low-noise amplifier with precise DC bias control via base resistor network. Use Value: Tight hFE2 classification and low V_CE(sat) maintain gain accuracy and dynamic headroom over temperature.
Audio Tone Control Buffer	Push-Pull Output Driver
Use Scenario: Isolating tone stack networks from downstream loading effects in guitar effects pedals. IC Role / Device Role / Timing Role: Emitter-follower buffer providing high input impedance and low output impedance. Use Value: V_CE(sat) ≤ −0.3 V and f_T ≥ 50 MHz preserve frequency response up to 20 kHz.	Use Scenario: Complementary pair with KSC2784 in Class AB headphone driver output stage. IC Role / Device Role / Timing Role: PNP half of symmetrical push-pull pair delivering negative half-cycle current. Use Value: Matched hFE2 range and identical TO-92S package simplify thermal coupling and layout symmetry.

Microphone Preamp

Phono Stage Amplifier

Use Scenario: Amplifying weak signals from condenser microphones with minimal added noise.

IC Role / Device Role / Timing Role: PNP BJT configured in common-emitter topology for high-input-impedance, low-noise voltage gain.

Use Value: NV = 25–40 mV and hFE ≥ 200 ensure SNR preservation at sub-mV input levels.

Use Scenario: Boosting RIAA-equalized signals from magnetic phono cartridges before line-level processing.

IC Role / Device Role / Timing Role: First-stage low-noise amplifier with precise DC bias control via base resistor network.

Use Value: Tight hFE2 classification and low V_CE(sat) maintain gain accuracy and dynamic headroom over temperature.

Audio Tone Control Buffer

Push-Pull Output Driver

Use Scenario: Isolating tone stack networks from downstream loading effects in guitar effects pedals.

IC Role / Device Role / Timing Role: Emitter-follower buffer providing high input impedance and low output impedance.

Use Value: V_CE(sat) ≤ −0.3 V and f_T ≥ 50 MHz preserve frequency response up to 20 kHz.

Use Scenario: Complementary pair with KSC2784 in Class AB headphone driver output stage.

IC Role / Device Role / Timing Role: PNP half of symmetrical push-pull pair delivering negative half-cycle current.

Use Value: Matched hFE2 range and identical TO-92S package simplify thermal coupling and layout symmetry.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP low-noise audio amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
KSA992F	Higher hFE (300–600), same V_CEO/I_C, TO-92 package (not TO-92S)	Slightly taller package may require board rework; higher gain increases sensitivity to thermal drift	Preferred where tighter hFE tolerance is needed and mechanical fit permits
MPSA92	Lower f_T (50 MHz typ), wider hFE spread (50–250), same TO-92S pinout	Less suitable for wideband audio; acceptable for general-purpose low-gain stages	Cost-effective option when noise and bandwidth requirements are relaxed

Compared with KSA1174FTA, KSA992F offers higher gain consistency but requires mechanical verification, while MPSA92 provides broader availability and lower cost at the expense of noise and bandwidth performance - making KSA1174FTA optimal for precision audio front-ends.

Availability

KSA1174FTA is available at Aetrix Electronics and suitable for microphone preamplifiers, phono stage amplifiers, tone control buffers, and push-pull output drivers requiring stable component supply and consistent low-noise performance.

Supply support for KSA1174FTA 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

ON Semiconductor is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions, with roots in Fairchild Semiconductor's analog and discrete product heritage.

The KSA1174FTA belongs to Fairchild's legacy audio transistor family, engineered specifically for low-noise, high-linearity analog signal amplification in consumer and professional audio systems.

FAQ

What is the pin configuration of the KSA1174FTA?

The KSA1174FTA uses a TO-92S package with pin 1 = Emitter, pin 2 = Collector, pin 3 = Base - verified per Fairchild Rev. A2 datasheet and dimensional drawings. This configuration is consistent across all KSA1174 variants and matches standard PNP orientation for through-hole audio amplifier layouts.

Is the KSA1174FTA suitable for switching applications?

The KSA1174FTA is characterized and optimized for linear amplification, not switching. While it can saturate (V_CE(sat) ≤ −0.3 V), its specified f_T, hFE, and noise parameters target analog gain stability - not fast turn-on/turn-off. For switching, dedicated low-V_CE(sat) or logic-compatible transistors are recommended instead of KSA1174FTA.

What does "hFE2 Classification P" mean for the KSA1174FTA?

"hFE2 Classification P" indicates the KSA1174FTA is binned for DC current gain between 200 and 400 when measured at V_CE = −6 V and I_C = −1 mA - a tighter specification than generic hFE1. This grading ensures predictable bias point stability in production audio circuits where gain consistency directly affects distortion and level matching.

How does the KSA1174FTA compare to the KSC2784?

The KSA1174FTA is the designated PNP complement to the NPN KSC2784, sharing matched V_CEO, I_C, P_C, and TO-92S packaging. Their symmetric hFE ranges and thermal characteristics enable balanced push-pull operation - a pairing explicitly called out in the original Fairchild documentation for the KSA1174FTA.

What is the maximum operating temperature for the KSA1174FTA?

The KSA1174FTA has a maximum junction temperature (T_J) of 150°C and a storage temperature range of −55°C to +150°C. Its power dissipation derates linearly from 300 mW at 25°C ambient to zero at 175°C - meaning sustained operation above 150°C junction temperature violates absolute maximum ratings and risks permanent degradation of the KSA1174FTA.

KSA1174FTA Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 50 mA

Voltage - Collector Emitter Breakdown (Max):: 120 V

Vce Saturation (Max) @ Ib, Ic:: 300mV @ 1mA, 10mA

Current - Collector Cutoff (Max):: 1µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 300 @ 1mA, 6V

Power - Max:: 300 mW

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92S

KSA1174FTA FAQ

1.How can I place an order for KSA1174FTA through Aetrix?

Please submit a Request for Quotation (RFQ) for KSA1174FTA 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 KSA1174FTA reliable?

The price and inventory of KSA1174FTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSA1174FTA is usually 5 days.

3.What payment methods are accepted for KSA1174FTA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSA1174FTA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSA1174FTA?

KSA1174FTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSA1174FTA 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 KSA1174FTA?

For technical support, including KSA1174FTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSA1174FTA requirements.

6.How does Aetrix verify that KSA1174FTA is sourced from the original manufacturer or authorized distributors?

All KSA1174FTA 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 KSA1174FTA meets industry standards.

7.What is the process for return or replacement of KSA1174FTA?

All KSA1174FTA units undergo pre-shipment inspection (PSI). If there is an issue with KSA1174FTA, 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 KSA1174FTA part is unused and in its original packaging.

Return procedure for KSA1174FTA:

1.Submit a request within 90 days.

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

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