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onsemi KSC1173YTSTU
- Part No.:
- KSC1173YTSTU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-220-3
- Datasheet:
-
KSC1173YTSTU.pdf
- Description:
- TRANS NPN 30V 3A TO-220-3
- Quantity:
- Payment:
- Shipping:
Inventory:8,171
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Product details
Overview
KSC1173YTSTU from Fairchild Semiconductor is an NPN epitaxial silicon power transistor designed for low-frequency amplifier and linear regulator applications, with 3 A collector current capability, 10 W collector dissipation at TC = 25°C, and 30 V collector-emitter breakdown voltage, commonly used in audio output stages and DC-DC linear regulators.
For engineers reviewing the KSC1173YTSTU datasheet, pinout, applications, or equivalent options, key selection criteria include safe operating area (SOA) limits, hFE classification (Y: 120–240 at IC = 0.5 A), VCE(sat) ≤ 0.8 V at IC = 2 A/IB = 0.2 A, and TO-220 thermal derating behavior above 25°C case temperature.
Technical Context
This discrete NPN bipolar junction transistor operates in linear or switching mode with a transition frequency fT of 100 MHz at VCE = 2 V, IC = 0.5 A, enabling stable gain in audio-band amplifiers. Its complementary pair KSA473 supports push-pull configurations.
The device exhibits low saturation voltage (VCE(sat) ≤ 0.8 V) under high-current drive and maintains hFE ≥ 25 even at IC = 2.5 A, supporting robust current-handling in regulated power supplies where base drive margin and thermal stability are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IC (Max) | 3 A - Supports continuous load currents up to 3 A in linear regulator or Class-A/B amplifier output stages |
| PC (TC=25°C) | 10 W - Enables high-power dissipation with external heatsinking; derates linearly above 25°C case temperature |
| BVCEO | 30 V - Sets maximum allowable supply rail voltage in low-voltage power amplifier and regulator designs |
| hFE (Y-class) | 120–240 - Ensures predictable base drive requirements and loop gain stability in feedback-controlled linear circuits |
| VCE(sat) | ≤ 0.8 V @ IC = 2 A, IB = 0.2 A - Minimizes conduction loss and heat generation in saturated-switching or quasi-saturated regulator use |
| fT | 100 MHz - Confirms usable gain bandwidth for audio-frequency amplification without high-frequency instability |
| Cob | 35 pF @ VCB = 10 V - Limits Miller capacitance impact on high-speed switching transitions and amplifier stability |
Pinout & Package
Package: TO-220 (3-pin, straight lead, insulated tab). Mounting requires electrically isolated heatsink interface due to collector-connected tab.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Base) | Control input | Receives forward-biased current to enable conduction; requires current-limiting resistor in most driver circuits |
| 2 (Collector) | High-side power path | Internally connected to metal tab; must be electrically isolated from heatsink unless system ground reference permits |
| 3 (Emitter) | Low-side return path | Serves as common emitter node; often tied to ground or negative rail in single-supply amplifier configurations |
Key Features
| Feature | Design Value |
|---|---|
| Complementary pairing | Designed as direct complement to PNP KSA473 for push-pull output stages and differential amplifiers |
| Thermal robustness | Junction temperature rating of 150°C supports operation in enclosed industrial enclosures with limited airflow |
| Low leakage | ICBO ≤ 1.0 μA at VCB = 20 V ensures minimal standby current in battery-backed or low-power standby circuits |
| SOA compliance | Defined safe operating area curve (Fig. 6) enables reliable design of linear regulators without secondary breakdown risk |
Applications
| Audio Power Amplifier | Linear Voltage Regulator |
|---|---|
Use Scenario: Output stage in 10–20 W Class-AB audio amplifiers driving 4–8 Ω speakers. IC Role / Device Role / Timing Role: NPN output transistor delivering amplified current to speaker load while maintaining linearity and thermal stability. Use Value: Low VCE(sat) and high hFE reduce crossover distortion and improve efficiency within audio band; SOA curve validates reliability under reactive loads. | Use Scenario: Pass element in adjustable positive linear regulators (e.g., LM317-based circuits) supplying up to 3 A. IC Role / Device Role / Timing Role: Series pass transistor regulating output voltage by dissipating excess input-output differential as heat. Use Value: 10 W dissipation rating and 150°C TJ allow sustained 2–3 A output with appropriate heatsinking and ambient derating. |
| DC Motor Driver (Low-Freq) | Power Supply Protection Circuit |
Use Scenario: Single-ended switch controlling small DC motors (e.g., fans, actuators) in industrial control panels. IC Role / Device Role / Timing Role: Low-frequency switching element turning motor on/off via base drive; not intended for PWM above ~10 kHz. Use Value: High IC rating and rugged SOA support inductive kickback handling; Cob = 35 pF minimizes switching losses at low frequencies. | Use Scenario: Current-limiting or foldback element in overcurrent-protected bench power supplies. IC Role / Device Role / Timing Role: Active current-sensing transistor in emitter-follower configuration feeding feedback to error amplifier. Use Value: Tight hFE tolerance (Y-class: 120–240) ensures repeatable current threshold setting; low VBE(on) improves sensing accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN power transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MJD127G | Higher BVCEO (80 V), lower hFE (20–70), TO-263 package | Better suited for higher-voltage switching; less suitable for precision linear regulation due to wider hFE spread | Select when >40 V supply rails or surface-mount assembly required; verify SOA compatibility for linear use |
| TIP31C | Same TO-220, BVCEO = 100 V, hFE = 10–50, PC = 40 W | Higher voltage margin but coarser hFE control and higher VCE(sat); optimized for switching over linear | Prefer for general-purpose switching; avoid in low-distortion audio or tight-regulation linear designs where KSC1173YTSTU's Y-class hFE matters |
Compared with MJD127G and TIP31C, KSC1173YTSTU offers tighter hFE consistency (Y-class), lower VCE(sat), and SOA curves validated for linear operation-making it preferable for audio amplification and precision linear regulation where gain stability and thermal predictability are critical.
Availability
KSC1173YTSTU is available at Aetrix Electronics and suitable for audio power amplifiers, linear voltage regulators, low-frequency motor drivers, and power supply protection circuits requiring stable component supply and long-term industrial availability.
Supply support for KSC1173YTSTU 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 company specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016.
The KSC1173YTSTU belongs to Fairchild's legacy low-frequency power transistor family, engineered specifically for linear-mode applications including audio amplification and analog voltage regulation where gain consistency and SOA integrity are prioritized over switching speed.
FAQ
What is the pin configuration of the KSC1173YTSTU?
The KSC1173YTSTU uses a TO-220 package with pinout: Pin 1 = Base, Pin 2 = Collector (connected to metal tab), Pin 3 = Emitter. The collector tab requires electrical isolation from the heatsink unless the system design intentionally references the collector to chassis ground.
Is the KSC1173YTSTU suitable for linear regulator applications?
Yes, the KSC1173YTSTU is explicitly rated for linear regulator use with 10 W collector dissipation at TC = 25°C and a defined safe operating area (SOA) curve. Its low VCE(sat) ≤ 0.8 V and Y-class hFE (120–240) support stable, low-distortion regulation in adjustable positive supplies up to 3 A.
What does the 'Y' suffix in KSC1173YTSTU indicate?
Per Fairchild's datasheet, the 'Y' denotes hFE classification: KSC1173YTSTU has DC current gain of 120–240 at VCE = 2 V and IC = 0.5 A. This tighter hFE bin improves predictability in feedback loops and reduces base drive variation across production units compared to standard 'O'-class (70–140).
How does thermal derating work for the KSC1173YTSTU?
The KSC1173YTSTU derates linearly from 10 W at TC = 25°C to zero at TC = 150°C, per Figure 7 in the datasheet. For example, at TC = 75°C, maximum allowable dissipation is 6.7 W. Heatsink selection must account for this slope and ensure junction temperature stays ≤ 150°C under worst-case load and ambient conditions.
Can the KSC1173YTSTU replace the KSC1173 without changes?
Yes, KSC1173YTSTU is a variant of the base KSC1173 with Y-class hFE binning and TO-220 packaging (TSTU suffix indicates tape-and-reel packaging with lead-free finish). Electrical specifications, pinout, and thermal characteristics match the original KSC1173, making it a direct functional and mechanical replacement in all compatible designs.
KSC1173YTSTU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-3
- Packaging:
- Tube
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- 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
KSC1173YTSTU FAQ
1.How can I place an order for KSC1173YTSTU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSC1173YTSTU 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 KSC1173YTSTU reliable?
The price and inventory of KSC1173YTSTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSC1173YTSTU is usually 5 days.
3.What payment methods are accepted for KSC1173YTSTU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSC1173YTSTU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSC1173YTSTU?
KSC1173YTSTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSC1173YTSTU 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 KSC1173YTSTU?
For technical support, including KSC1173YTSTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSC1173YTSTU requirements.
6.How does Aetrix verify that KSC1173YTSTU is sourced from the original manufacturer or authorized distributors?
All KSC1173YTSTU 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 KSC1173YTSTU meets industry standards.
7.What is the process for return or replacement of KSC1173YTSTU?
All KSC1173YTSTU units undergo pre-shipment inspection (PSI). If there is an issue with KSC1173YTSTU, 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 KSC1173YTSTU part is unused and in its original packaging.
Return procedure for KSC1173YTSTU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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