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onsemi KSD471ACYBU
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- Part No.:
- KSD471ACYBU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
KSD471ACYBU.pdf
- Description:
- TRANS NPN 30V 1A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,953
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Product details
Overview
KSD471ACYBU from onsemi is an NPN epitaxial silicon transistor designed for audio frequency power amplification, with a 1 A collector current rating, 800 mW collector power dissipation, and 30 V collector-emitter breakdown voltage. It serves as a medium-power switching and linear amplification device in consumer audio output stages, low-voltage DC-DC converter drivers, and relay interface circuits.
For engineers reviewing the KSD471ACYBU datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-92-3LF package, center-collector pinout (Emitter-Base-Collector), DC current gain range of 120–240 at 100 mA, saturation voltage ≤0.5 V at 1 A/0.1 A drive, and 130 MHz fT bandwidth capability.
Technical Context
This transistor operates as a general-purpose NPN bipolar junction device optimized for audio-frequency linear amplification and moderate-speed switching. Its 150 °C maximum junction temperature and −55 to +150 °C storage range support industrial ambient operation.
The device features a fixed center-collector configuration (pin 1 = Emitter, pin 2 = Base, pin 3 = Collector), complementary pairing with KSB1151 (PNP), and exhibits 16 pF output capacitance at 6 V VCB, enabling stable performance in Class-A/B amplifier output stages and low-noise pre-driver applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 30 V - Supports rail voltages up to ±15 V in push-pull audio output stages without breakdown. |
| IC | 1 A - Delivers sufficient current for driving 4–8 Ω speakers or small solenoids directly. |
| PC | 800 mW - Enables continuous operation in compact TO-92 packages with minimal heatsinking. |
| hFE | 120–240 @ VCE = 1 V, IC = 100 mA - Provides predictable bias stability in emitter-follower and common-emitter configurations. |
| fT | 130 MHz - Ensures adequate gain margin and phase response up to mid-audio frequencies (≤20 kHz) with low distortion. |
| VCE(sat) | ≤0.5 V @ IC = 1 A, IB = 0.1 A - Minimizes conduction loss in switching applications such as LED or relay drivers. |
| Cob | 16 pF @ VCB = 6 V - Limits high-frequency feedback and stabilizes amplifier compensation networks. |
Pinout & Package
Package: TO-92-3LF (lead-free, case 135AR), 4.83 mm × 4.76 mm lead-formed outline, center-collector configuration.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Emitter | Current sink node; connects to ground or low-side return path in common-emitter topology. |
| 2 | Base | Control input; requires ~0.1 A drive current for full saturation at 1 A collector load. |
| 3 | Collector | Current source node; ties to positive supply or load high-side in switching or amplification roles. |
Key Features
| Feature | Design Value |
|---|---|
| Complementary PNP pair | Matched electrical behavior with KSB1151 for push-pull amplifier symmetry and thermal tracking. |
| Center-collector pinout | Standardized pin 3 collector layout simplifies PCB routing and reduces trace inductance in high-current paths. |
| 130 MHz fT | Enables stable small-signal gain beyond 100 kHz, supporting wideband audio and fast-switching control loops. |
| Low VBE(sat) | ≤1.2 V at 1 A ensures efficient base drive from microcontroller GPIO or logic-level sources without external buffers. |
| Pb-free TO-92-3LF | RoHS-compliant packaging meets industrial environmental compliance requirements without solderability compromise. |
Applications
| Audio Power Amplifier Stage | DC-DC Converter Driver |
|---|---|
Use Scenario: Final output stage in battery-powered portable audio systems delivering 0.5–1 W into 8 Ω loads. IC Role / Device Role / Timing Role: Linear NPN amplifier operating in Class-A/B mode with fixed bias network. Use Value: 30 V VCEO and 1 A IC enable direct coupling to single-supply rails up to 24 V while maintaining THD <1% at 1 kHz. |
Use Scenario: High-side switch in 5–12 V buck converter gate driver circuits controlling external MOSFETs. IC Role / Device Role / Timing Role: Saturated switch providing fast turn-on/turn-off of power FET gates with low VCE(sat). Use Value: 0.5 V VCE(sat) minimizes driver-stage conduction loss, improving overall converter efficiency by ≥0.8% at 1 A peak gate current. |
| Relay Interface Circuit | LED Current Regulator |
Use Scenario: Microcontroller-driven electromechanical relay coil driver in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Medium-current saturated switch interfacing 3.3 V/5 V logic to 12–24 V relay coils. Use Value: 1 A IC rating supports relays with coil currents up to 800 mA; 800 mW PC allows continuous duty without heatsink. |
Use Scenario: Constant-current sink for high-brightness indicator LEDs in automotive dashboard backlighting. IC Role / Device Role / Timing Role: Linear current regulator using emitter resistor feedback and base bias control. Use Value: hFE consistency (120–240) enables ±5% LED current tolerance across production lots without trimming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMBT4401LT1G | Higher fT (250 MHz), lower PC (310 mW), SOT-23 package, max IC = 600 mA. | Better for high-speed digital switching but unsuitable for 1 A continuous audio output loads. | Select when board space is constrained and current demand ≤600 mA; verify thermal derating at elevated ambient. |
| KSC1845FTA | Same TO-92-3LF package, higher VCEO (60 V), lower hFE (60–120), PC = 625 mW. | Preferred for higher-voltage relay drivers or flyback snubbers where breakdown margin >40 V is required. | Choose for 48 V system interfaces; accept reduced DC gain and tighter thermal limits versus KSD471ACYBU. |
Compared with MMBT4401LT1G and KSC1845FTA, the KSD471ACYBU uniquely balances 1 A current handling, 800 mW power dissipation, and TO-92 mechanical compatibility-making it the only option among the three capable of sustained 1 A linear operation in legacy audio and industrial control designs.
Availability
KSD471ACYBU is available at Aetrix Electronics and suitable for audio power amplifiers, relay interface circuits, and DC-DC converter drivers requiring stable component supply and long-lifecycle support for industrial and consumer electronics.
Supply support for KSD471ACYBU 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 ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics, delivering power management, analog, sensor, and discrete solutions.
The KSD471ACYBU belongs to onsemi's general-purpose bipolar transistor product line, engineered for cost-sensitive, medium-power linear and switching applications in audio, industrial controls, and power conversion.
FAQ
What is the pin configuration of the KSD471ACYBU?
The KSD471ACYBU uses a center-collector TO-92-3LF pinout: Pin 1 is Emitter, Pin 2 is Base, and Pin 3 is Collector. This configuration is confirmed in the official onsemi datasheet (Rev 4, January 2026) and matches the marking diagram "AD4 71AY YWW". The device is not pin-compatible with standard emitter-collector-base variants.
Is the KSD471ACYBU still in active production?
No-the KSD471ACYBU is officially discontinued per the onsemi datasheet Rev 4 (January 2026), which states "DISCONTINUED: This device is not recommended for new design." However, Aetrix Electronics maintains legacy inventory and offers lifecycle coordination support for existing production programs relying on KSD471ACYBU.
What is the maximum safe operating collector current for KSD471ACYBU at 70°C ambient?
At 70°C ambient, the KSD471ACYBU's maximum continuous collector current must be derated from 1 A due to thermal limits. With a junction-to-ambient thermal resistance (RθJA) of ~200 °C/W for TO-92-3LF and TJ(max) = 150 °C, the allowable IC drops to approximately 400 mA to maintain safe junction temperature-verified via onsemi's Safe Operating Area (SOA) curve in Figure 6.
How does the KSD471ACYBU compare to the KSD471ACYTA variant?
The KSD471ACYBU and KSD471ACYTA share identical electrical specifications and die, differing only in packaging: KSD471ACYBU uses TO-92-3LF (lead-formed, case 135AR), while KSD471ACYTA uses standard TO-92-3 (case 135AN). Both are Pb-free, but KSD471ACYBU's lead-formed leads simplify automated insertion and reduce mechanical stress during board flexure.
Can the KSD471ACYBU replace the KSD471A in existing designs?
Yes-the KSD471ACYBU is a Pb-free, lead-formed version of the original KSD471A, with identical absolute maximum ratings, electrical characteristics, and pinout. The "YBU" suffix denotes TO-92-3LF packaging per onsemi's ordering table; no circuit redesign or layout change is needed when migrating from KSD471A to KSD471ACYBU.
KSD471ACYBU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 1 A
- Voltage - Collector Emitter Breakdown (Max):
- 30 V
- Vce Saturation (Max) @ Ib, Ic:
- 500mV @ 100mA, 1A
- Current - Collector Cutoff (Max):
- 100nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 120 @ 100mA, 1V
- Power - Max:
- 800 mW
- Frequency - Transition:
- 130MHz
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
KSD471ACYBU FAQ
1.How can I place an order for KSD471ACYBU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSD471ACYBU 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 KSD471ACYBU reliable?
The price and inventory of KSD471ACYBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSD471ACYBU is usually 5 days.
3.What payment methods are accepted for KSD471ACYBU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSD471ACYBU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSD471ACYBU?
KSD471ACYBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSD471ACYBU 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 KSD471ACYBU?
For technical support, including KSD471ACYBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSD471ACYBU requirements.
6.How does Aetrix verify that KSD471ACYBU is sourced from the original manufacturer or authorized distributors?
All KSD471ACYBU 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 KSD471ACYBU meets industry standards.
7.What is the process for return or replacement of KSD471ACYBU?
All KSD471ACYBU units undergo pre-shipment inspection (PSI). If there is an issue with KSD471ACYBU, 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 KSD471ACYBU part is unused and in its original packaging.
Return procedure for KSD471ACYBU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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