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onsemi KSE170STU
- Part No.:
- KSE170STU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-225AA, TO-126-3
- Datasheet:
-
KSE170STU.pdf
- Description:
- TRANS PNP 40V 3A TO-126-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,767
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Product details
Overview
KSE170STU from Fairchild Semiconductor is a PNP epitaxial silicon transistor rated for -40 V VCEO, -60 V VCBO, -3 A continuous collector current, 12.5 W collector dissipation at TC = 25°C, and 50 MHz fT, used in low-power audio amplifiers and high-speed switching circuits.
For engineers reviewing the KSE170STU datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP polarity, TO-126 package thermal performance, DC current gain (hFE = 50–250), saturation voltage behavior under pulsed loads, and safe operating area limits up to 150°C junction temperature.
Technical Context
This device operates as a medium-power PNP bipolar junction transistor with fixed emitter-base and collector-base junction structures optimized for linear amplification and switching. Its hFE varies from 50 at IC = –100 mA to 12 at IC = –1.5 A, and VCE(sat) reaches –1.7 V at IC = –3 A / IB = –600 mA.
Thermal design relies on case-mounted heat sinking: 12.5 W power dissipation is only valid at TC = 25°C, dropping to 1.5 W at ambient (TA = 25°C) due to TO-126 package limitations. Cob = 50 pF at VCB = –10 V supports moderate-frequency switching up to ~50 MHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | –40 V - Maximum allowable collector-emitter voltage before breakdown in common-emitter configuration |
| IC (DC) | –3 A - Continuous collector current rating defining steady-state conduction capability |
| hFE | 50–250 - DC current gain range across IC = –100 mA to –500 mA, critical for bias stability in amplifier stages |
| VCE(sat) | –0.3 V to –1.7 V - Saturation voltage span indicating on-state loss at varying load currents and drive levels |
| fT | 50 MHz - Current gain bandwidth product limiting small-signal amplification and switching speed |
| Cob | 50 pF - Output capacitance at VCB = –10 V, directly affecting high-frequency response and switching transition times |
| PC (TC=25°C) | 12.5 W - Maximum power dissipation achievable with adequate heatsinking at case temperature of 25°C |
Pinout & Package
Package: TO-126 - Three-lead, through-hole plastic power package with metal tab for heatsink mounting; lead spacing matches standard 0.1" pitch PCB footprints.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | Emission terminal for majority carriers (holes) | Connected to most positive rail in PNP configurations; determines current sourcing direction and bias reference point |
| 2 (Collector) | Current collection terminal | Typically tied to load or supply return; voltage swing here defines output dynamic range and power handling |
| 3 (Base) | Control electrode for carrier injection | Receives forward-biased current to modulate collector-emitter conduction; requires external current-limiting resistor |
Key Features
| Feature | Design Value |
|---|---|
| High fT bandwidth | 50 MHz enables use in audio preamplifier stages and medium-speed digital switching up to ~10 MHz |
| Wide hFE range | 50–250 supports both high-gain small-signal amplification and robust current-driving capability |
| Low VBE(on) | –1.2 V at IC = –500 mA simplifies base drive circuit design and reduces quiescent power loss |
| TO-126 thermal interface | Metal tab allows direct mechanical and thermal attachment to heatsinks, enabling 12.5 W operation with proper mounting |
| Rated junction temperature | 150°C maximum TJ permits reliable operation in industrial ambient environments up to 85°C with appropriate derating |
Applications
| Audio Preamp Stage | DC Motor Driver Switch |
|---|---|
Use Scenario: Low-noise voltage amplification in battery-powered portable audio equipment with single-supply rails. IC Role / Device Role / Timing Role: PNP transistor configured in common-emitter topology to provide inverted gain with minimal distortion. Use Value: hFE ≥ 50 at IC = –100 mA ensures stable biasing; fT = 50 MHz preserves full audio bandwidth up to 20 kHz. | Use Scenario: Driving small brushed DC motors (≤24 V, ≤2 A) in industrial actuators and robotics subsystems. IC Role / Device Role / Timing Role: Medium-current PNP switch controlling motor current path between supply and ground. Use Value: VCE(sat) = –0.9 V at IC = –1.5 A minimizes conduction loss; TO-126 package supports intermittent 3 A pulses. |
| LED Constant-Current Source | Linear Voltage Regulator Pass Element |
Use Scenario: Precision current regulation for high-brightness LED strings in signage and instrumentation backlighting. IC Role / Device Role / Timing Role: Emitter-follower configured PNP providing stable current sink with feedback control. Use Value: VBE(on) = –1.2 V enables accurate current setpoint via sense resistor; low Cob avoids instability in closed-loop designs. | Use Scenario: Pass transistor in adjustable linear regulators delivering up to 1.5 A output with low dropout requirements. IC Role / Device Role / Timing Role: Series pass element regulating output voltage by dissipating excess input-output differential. Use Value: 12.5 W PC at TC = 25°C supports >5 V dropout at 1.5 A; SOA curve validated to 100 µs pulse width. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MJD2955G | VCEO = –70 V, IC = –10 A, hFE = 20–100, TO-220 package | Higher voltage/current rating; larger footprint and thermal mass | Preferred where higher breakdown margin or sustained >3 A loads are required; requires PCB layout change |
| KSA992FBU | VCEO = –30 V, IC = –1.5 A, hFE = 60–240, SOT-32 package | Lower voltage/current, surface-mount, reduced thermal capacity | Suitable for space-constrained low-power designs; not interchangeable without thermal redesign |
Compared with KSE170STU, MJD2955G offers greater ruggedness and power handling but demands larger heatsinking, while KSA992FBU provides compact SMT integration at the cost of reduced voltage margin and thermal headroom.
Availability
KSE170STU is available at Aetrix Electronics and suitable for low-power audio amplifiers, DC motor drivers, LED constant-current sources, and linear voltage regulator pass elements requiring stable component supply and long-term industrial availability.
Supply support for KSE170STU 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 components before its acquisition by ON Semiconductor in 2016.
The KSE170STU belongs to Fairchild's legacy general-purpose PNP transistor family designed for cost-sensitive industrial and consumer linear/switching applications requiring proven reliability and broad thermal operating range.
FAQ
What is the maximum collector-emitter voltage rating for KSE170STU?
The KSE170STU has a maximum collector-emitter voltage (VCEO) rating of –40 V at TC = 25°C. This rating applies under open-base conditions and must be derated linearly above 25°C case temperature per the datasheet's thermal characteristics curve. Exceeding this limit risks avalanche breakdown and permanent device failure. The KSE170STU is not rated for higher voltages like the KSE171 or KSE172 variants.
Does KSE170STU support surface-mount assembly?
No, the KSE170STU uses a through-hole TO-126 package with three leads and a metal tab for heatsinking. It is not compatible with reflow soldering or pick-and-place automation for SMT lines. For surface-mount alternatives, consider the KSA992FBU (SOT-32) or MMBT2907A (SOT-23), though these differ significantly in voltage, current, and thermal capability compared to the KSE170STU.
What is the typical DC current gain (hFE) of KSE170STU at 500 mA collector current?
At VCE = –1 V and IC = –500 mA, the KSE170STU exhibits a typical hFE of 30, with a guaranteed minimum of 50 and maximum of 250 across the production lot. This wide spread reflects process variation inherent to bipolar transistors and necessitates design margining-especially in bias-critical linear amplifier stages where gain stability affects distortion and output impedance.
Can KSE170STU be used in complementary pairs with NPN transistors?
Yes, the KSE170STU is commonly paired with the NPN KSC1845 or 2N3055 in Class AB audio output stages. Its –40 V VCEO, –3 A IC, and matching TO-126 footprint enable symmetrical push-pull operation. However, exact gain and VBE tracking require binning or external emitter degeneration resistors to minimize crossover distortion in the KSE170STU-based half of the pair.
What thermal derating applies to KSE170STU when operated at 85°C case temperature?
At TC = 85°C, the KSE170STU's maximum collector dissipation drops to approximately 7.5 W-derated linearly from 12.5 W at 25°C using the datasheet's 0.1 W/°C slope. This means sustained operation at full 3 A current requires either reduced voltage swing or active cooling. The 150°C maximum junction temperature remains unchanged, but thermal resistance from junction-to-case (RθJC) must be combined with heatsink RθCS + RθSA to ensure safe operation.
KSE170STU 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):
- 3 A
- Voltage - Collector Emitter Breakdown (Max):
- 40 V
- Vce Saturation (Max) @ Ib, Ic:
- 1.7V @ 600mA, 3A
- Current - Collector Cutoff (Max):
- 100nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 50 @ 100mA, 1V
- Power - Max:
- 1.5 W
- Frequency - Transition:
- 50MHz
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-126-3
KSE170STU FAQ
1.How can I place an order for KSE170STU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSE170STU 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 KSE170STU reliable?
The price and inventory of KSE170STU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSE170STU is usually 5 days.
3.What payment methods are accepted for KSE170STU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSE170STU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSE170STU?
KSE170STU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSE170STU 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 KSE170STU?
For technical support, including KSE170STU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSE170STU requirements.
6.How does Aetrix verify that KSE170STU is sourced from the original manufacturer or authorized distributors?
All KSE170STU 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 KSE170STU meets industry standards.
7.What is the process for return or replacement of KSE170STU?
All KSE170STU units undergo pre-shipment inspection (PSI). If there is an issue with KSE170STU, 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 KSE170STU part is unused and in its original packaging.
Return procedure for KSE170STU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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