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 KSA473YTU

Name: KSA473YTU
Brand: onsemi
SKU: KSA473YTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: KSA473YTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: KSA473YTU.pdf

Description:: TRANS PNP 30V 3A TO-220-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:3,674

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

Product details

Overview

KSA473YTU from ON Semiconductor is a PNP epitaxial silicon power transistor in TO-220 package, rated for −3 A collector current and 10 W collector dissipation at TC = 25°C, with −30 V V_CEO and −30 V V_CBO, commonly used in low-frequency power amplifier and linear regulator circuits.

For engineers reviewing the KSA473YTU datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed h_FE range (70–240), V_CE(sat) ≤ −0.8 V at −2 A/−0.2 A, f_T = 100 MHz, and safe operating area compliance for continuous and pulsed operation up to 150°C junction temperature.

Technical Context

The KSA473YTU operates as a medium-power PNP bipolar junction transistor optimized for linear and switching applications below 100 MHz. Its DC current gain is specified in two test conditions: h_FE1 ≥ 70 at −0.5 A and h_FE2 ≥ 25 at −2.5 A, supporting stable biasing across load ranges.

It features low saturation voltage (V_CE(sat) ≤ −0.8 V), tight breakdown voltage matching (V_CBO = V_CEO = −30 V), and complementary pairing with KSC1173 (NPN). Thermal derating begins at TC > 25°C, with full 10 W dissipation only at case temperature ≤ 25°C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−30 V - Maximum allowable collector-emitter voltage before avalanche breakdown; defines safe DC rail headroom in regulator or amplifier stages.
I_C	−3 A - Continuous collector current rating; supports output stages delivering up to 3 A of sink current.
P_C (T_C=25°C)	10 W - Maximum steady-state power dissipation at case temperature 25°C; requires heatsinking for sustained operation above ambient.
h_FE	70–240 - DC current gain range across operating points; enables predictable base drive sizing for both small-signal and high-current biasing.
f_T	100 MHz - Current gain bandwidth product; confirms suitability for audio and low-speed switching up to ~10 MHz practical bandwidth.
V_CE(sat)	≤ −0.8 V @ −2 A/−0.2 A - Low saturation voltage reduces conduction loss and thermal stress in linear regulators and Class-A/B amplifiers.

Pinout & Package

Package: TO-220 (3-pin, straight lead, insulated tab). Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base - confirmed per JEDEC TO-220AB mechanical drawing and Fairchild KSA473 Rev. A2 datasheet Figure 4 layout.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit path for PNP device	Connected to positive supply rail in common-emitter amplifier or regulator output stage; referenced for base bias network.
2 (Collector)	Main current input terminal	Typically tied to load or negative rail; carries full output current and must be thermally coupled to heatsink via metal tab.
3 (Base)	Control electrode for minority-carrier injection	Receives forward-biased current to turn on device; requires series resistor to limit I_B and ensure h_FE-based saturation.

Key Features

Feature	Design Value
Complementary pair to KSC1173	Enables matched push-pull output stages with symmetrical V_CEO, I_C, and h_FE characteristics for reduced crossover distortion.
Low V_CE(sat)	−0.3 V to −0.8 V ensures <1.6 W conduction loss at −2 A, improving thermal margin and efficiency in linear regulation.
High f_T	100 MHz bandwidth supports stable feedback loop compensation in audio amplifiers and fast-switching regulators.
JEDEC TO-220AB compliant	Standardized mechanical footprint allows drop-in replacement in existing PCB layouts and compatibility with industry-standard heatsinks.

Applications

Audio Power Amplifier	Linear Voltage Regulator
Use Scenario: Output stage in discrete Class-AB audio amplifier driving 4–8 Ω speakers at ≤10 W RMS. IC Role / Device Role / Timing Role: PNP output transistor providing current sinking capability in complementary symmetry configuration. Use Value: Low V_CE(sat) minimizes heat generation during high-current peaks, while h_FE stability ensures consistent gain across signal swing.	Use Scenario: Pass element in adjustable positive-voltage linear regulator (e.g., with LM317-based control circuit). IC Role / Device Role / Timing Role: Series pass transistor regulating output by varying emitter-collector conduction under base control. Use Value: 10 W dissipation rating and 150°C T_J allow reliable operation under worst-case dropout and load conditions without forced cooling.
DC Motor Driver (Low-Speed)	Power Supply Foldback Protection
Use Scenario: H-bridge half-bridge leg controlling bidirectional 12 V DC motor with stall current ≤3 A. IC Role / Device Role / Timing Role: High-side PNP switch enabling ground-referenced logic control of motor polarity. Use Value: −30 V V_CEO provides margin against inductive kickback; TO-220 thermal mass absorbs short-duration surge currents.	Use Scenario: Current-limiting element in foldback protection circuit limiting output to safe levels during overload or short-circuit. IC Role / Device Role / Timing Role: Active current-sense transistor modulating pass element conduction based on sensed load current. Use Value: Tight V_BE(on) (−0.75 to −1.0 V) enables accurate current threshold setting; Cob = 40 pF avoids instability in feedback loop.

Audio Power Amplifier

Linear Voltage Regulator

Use Scenario: Output stage in discrete Class-AB audio amplifier driving 4–8 Ω speakers at ≤10 W RMS.

IC Role / Device Role / Timing Role: PNP output transistor providing current sinking capability in complementary symmetry configuration.

Use Value: Low V_CE(sat) minimizes heat generation during high-current peaks, while h_FE stability ensures consistent gain across signal swing.

Use Scenario: Pass element in adjustable positive-voltage linear regulator (e.g., with LM317-based control circuit).

IC Role / Device Role / Timing Role: Series pass transistor regulating output by varying emitter-collector conduction under base control.

Use Value: 10 W dissipation rating and 150°C T_J allow reliable operation under worst-case dropout and load conditions without forced cooling.

DC Motor Driver (Low-Speed)

Power Supply Foldback Protection

Use Scenario: H-bridge half-bridge leg controlling bidirectional 12 V DC motor with stall current ≤3 A.

IC Role / Device Role / Timing Role: High-side PNP switch enabling ground-referenced logic control of motor polarity.

Use Value: −30 V V_CEO provides margin against inductive kickback; TO-220 thermal mass absorbs short-duration surge currents.

Use Scenario: Current-limiting element in foldback protection circuit limiting output to safe levels during overload or short-circuit.

IC Role / Device Role / Timing Role: Active current-sense transistor modulating pass element conduction based on sensed load current.

Use Value: Tight V_BE(on) (−0.75 to −1.0 V) enables accurate current threshold setting; Cob = 40 pF avoids instability in feedback loop.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD44H11T4G	TO-252 (DPAK), −8 A I_C, −80 V V_CEO, higher P_C = 15 W, f_T = 3 MHz	Better voltage/current headroom but lower bandwidth; suited for higher-voltage industrial supplies, not audio linearity-critical designs.	Select when higher V_CEO or I_C is required and surface-mount assembly is preferred over through-hole TO-220.
2SA1943	TO-3P, −15 A I_C, −230 V V_CEO, P_C = 150 W, f_T = 30 MHz, complementary to 2SC5200	Higher power and voltage class; used in high-fidelity audio amplifiers and RF linear stages where KSA473YTU lacks headroom.	Choose for high-power audio output stages requiring >10 W continuous dissipation and wider SOA; requires larger heatsink and PCB real estate.

Compared with MJD44H11T4G and 2SA1943, the KSA473YTU offers optimal balance of audio-grade linearity (100 MHz f_T, low V_CE(sat)), TO-220 mechanical compatibility, and cost-effective 10 W operation-making it ideal for mid-power discrete amplifier and regulator designs where precision and thermal manageability are prioritized over extreme ratings.

Availability

KSA473YTU is available at Aetrix Electronics and suitable for audio power amplifiers, linear voltage regulators, DC motor drivers, and power supply protection circuits requiring stable component supply and JEDEC-standard through-hole packaging.

Supply support for KSA473YTU 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 manufacturer specializing in energy-efficient power management, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The KSA473YTU belongs to ON Semiconductor's legacy discrete bipolar transistor portfolio, originally developed by Fairchild Semiconductor for general-purpose linear and switching power applications demanding reliability, thermal robustness, and complementary NPN/PNP pairing.

FAQ

What is the maximum junction temperature for the KSA473YTU?

The KSA473YTU has a maximum junction temperature (T_J) of 150°C, as specified in its Absolute Maximum Ratings table. This rating governs thermal design limits for continuous operation; derating curves in the datasheet show allowable power dissipation decreases linearly above case temperature 25°C. Engineers must ensure that actual KSA473YTU junction temperature remains ≤150°C under worst-case ambient, power, and heatsink conditions.

Is the KSA473YTU pin-compatible with the KSC1173?

No-the KSA473YTU (PNP) and KSC1173 (NPN) are complementary devices, not pin-compatible. They share identical TO-220 package outlines and pin numbering (Emitter-Collector-Base), but their polarity and biasing requirements differ fundamentally. When used together in push-pull stages, external circuitry must account for reversed voltage polarities and current directions; direct substitution without redesign is not possible.

What does the "YTU" suffix indicate in KSA473YTU?

The "YTU" suffix denotes a specific manufacturing variant and tape-and-reel packaging format per ON Semiconductor's post-Fairchild nomenclature standard. It indicates the device is supplied in TO-220 straight-lead configuration, lead-free (RoHS-compliant), and packed in 500-unit reels-consistent with ON Semiconductor's ordering codes for legacy Fairchild parts migrated into their system after the 2016 acquisition.

Can the KSA473YTU be used in switching applications?

Yes-the KSA473YTU supports switching operation up to frequencies where its 100 MHz f_T and 40 pF C_ob permit adequate gain and speed, typically ≤1–2 MHz for efficient hard-switching. Its −0.8 V V_CE(sat) and defined safe operating area (SOA) enable reliable pulse operation, but designers must verify switching losses, storage time (t_s), and secondary breakdown limits per application; it is not optimized for high-frequency SMPS primary-side switching.

How does the KSA473YTU's h_FE classification affect circuit design?

The KSA473YTU is offered in two h_FE bins: "O" (70–140) and "Y" (120–240). Circuit design must accommodate the full min–max range-especially in linear regulators where h_FE variation impacts base drive current and thermal stability. For critical biasing, use worst-case h_FE values (e.g., 70 for minimum drive, 240 for saturation margin) to ensure KSA473YTU functions correctly across all production units.

KSA473YTU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 3 A

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 800mV @ 200mA, 2A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 120 @ 500mA, 2V

Power - Max:: 10 W

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220-3

KSA473YTU FAQ

1.How can I place an order for KSA473YTU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSA473YTU 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 KSA473YTU reliable?

The price and inventory of KSA473YTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSA473YTU is usually 5 days.

3.What payment methods are accepted for KSA473YTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSA473YTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSA473YTU?

KSA473YTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSA473YTU 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 KSA473YTU?

For technical support, including KSA473YTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSA473YTU requirements.

6.How does Aetrix verify that KSA473YTU is sourced from the original manufacturer or authorized distributors?

All KSA473YTU 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 KSA473YTU meets industry standards.

7.What is the process for return or replacement of KSA473YTU?

All KSA473YTU units undergo pre-shipment inspection (PSI). If there is an issue with KSA473YTU, 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 KSA473YTU part is unused and in its original packaging.

Return procedure for KSA473YTU:

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…