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

onsemi KSD471AGTA

Name: KSD471AGTA
Brand: onsemi
SKU: KSD471AGTA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSD471AGTA

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: KSD471AGTA.pdf

Description:: TRANS NPN 30V 1A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSD471AGTA from ON Semiconductor is an NPN epitaxial silicon transistor designed for audio frequency power amplification, with a 1 A collector current rating, 800 mW power dissipation, and 30 V collector-emitter breakdown voltage. It serves as a complement to KSB564A in push-pull amplifier stages and is commonly used in low-voltage audio output stages of consumer electronics.

For engineers reviewing the KSD471AGTA datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain (h_FE = 120–400), saturation voltages (V_CE(sat) = 0.5 V at I_C = 1 A), junction temperature limit (150 °C), and TO-92 package compatibility for through-hole audio bias networks.

Technical Context

The KSD471AGTA operates as a general-purpose NPN bipolar junction transistor optimized for linear amplification in the audio band. Its 130 MHz f_T supports stable gain up to mid-audio frequencies, while its 16 pF output capacitance (C_ob) minimizes high-frequency loading in driver-stage configurations.

It features a fixed lead configuration (Emitter–Base–Collector) in TO-92 packaging, with absolute maximum ratings including V_CBO = 40 V, V_CEO = 30 V, and V_EBO = 5 V - defining safe operating limits for Class-A/B amplifier biasing and transient suppression.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	30 V - Maximum collector-emitter voltage before breakdown; sets upper rail limit for single-supply audio amplifiers
I_C	1 A - Continuous collector current capacity; supports ≥1 W output into 8 Ω loads with proper heatsinking
P_C	800 mW - Max power dissipation at 25 °C ambient; requires thermal derating above 25 °C per datasheet curve
h_FE	120–400 - DC current gain range across Y/G classifications; enables predictable base drive sizing in linear stages
V_CE(sat)	0.5 V @ I_C = 1 A, I_B = 0.1 A - Low saturation voltage reduces conduction loss and improves efficiency in switching-audio hybrids
f_T	130 MHz - Current gain-bandwidth product; ensures adequate gain margin beyond 20 kHz audio band
C_ob	16 pF @ V_CB = 6 V - Output capacitance affects high-frequency roll-off and stability in multi-stage designs

Pinout & Package

Package: TO-92, straight-lead JEDEC-compliant plastic package with center-collector variant (suffix "-C" confirmed). Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-impedance return path; defines reference for V_BE control
2 (Base)	Control input	Receives forward-biased current to modulate collector current; requires series resistor for current limiting
3 (Collector)	Current source terminal	Delivers amplified output current to load; connected to positive supply via collector resistor or transformer primary

Key Features

Feature	Design Value
Audio frequency power amplification	Optimized h_FE and f_T support stable linear operation up to 20 kHz with minimal distortion in Class-A/B stages
Complement to KSB564A	Enables matched push-pull pair design with symmetric NPN/PNP characteristics for reduced crossover distortion
TO-92 center-collector configuration	Standardized pinout (E-B-C) simplifies PCB layout reuse and manual assembly in legacy audio designs
150 °C junction temperature rating	Supports reliable operation in enclosed consumer enclosures without forced airflow or additional heatsinking

Applications

Portable Audio Amplifiers	TV Speaker Drivers
Use Scenario: Low-power stereo headphone or mono speaker output stage in battery-powered portable radios and Bluetooth speakers. IC Role / Device Role / Timing Role: NPN power switch/amplifier delivering 0.5–1 W into 4–8 Ω loads with Class-A/B biasing. Use Value: 800 mW power dissipation and 1 A current capability enable compact, thermally manageable output stages without external heat sinks.	Use Scenario: Mid-power audio output driver in 24–32 inch LCD/LED TVs where space and cost constrain integrated amplifier IC use. IC Role / Device Role / Timing Role: Discrete emitter-follower or common-emitter stage driving TV speaker coils directly from DAC or preamp outputs. Use Value: 30 V V_CEO accommodates typical 12–24 V TV supply rails; low V_CE(sat) preserves headroom and dynamic range.
Intercom Systems	Alarm Sounders
Use Scenario: Two-way voice amplification in wired building intercom units requiring bidirectional analog signal handling. IC Role / Device Role / Timing Role: Linear amplifier in both transmit and receive paths, often paired with KSB564A for complementary symmetry. Use Value: Matched h_FE classification (Y/G) ensures consistent gain matching between NPN/PNP pairs, minimizing harmonic imbalance.	Use Scenario: High-reliability audible alert driver in fire alarm panels, security systems, and industrial annunciators. IC Role / Device Role / Timing Role: Switch-mode audio driver toggling piezoelectric or electromagnetic sounders at 1–4 kHz. Use Value: 130 MHz f_T and fast saturation behavior support clean square-wave drive up to 4 kHz without ringing or overshoot.

Portable Audio Amplifiers

TV Speaker Drivers

Use Scenario: Low-power stereo headphone or mono speaker output stage in battery-powered portable radios and Bluetooth speakers.

IC Role / Device Role / Timing Role: NPN power switch/amplifier delivering 0.5–1 W into 4–8 Ω loads with Class-A/B biasing.

Use Value: 800 mW power dissipation and 1 A current capability enable compact, thermally manageable output stages without external heat sinks.

Use Scenario: Mid-power audio output driver in 24–32 inch LCD/LED TVs where space and cost constrain integrated amplifier IC use.

IC Role / Device Role / Timing Role: Discrete emitter-follower or common-emitter stage driving TV speaker coils directly from DAC or preamp outputs.

Use Value: 30 V V_CEO accommodates typical 12–24 V TV supply rails; low V_CE(sat) preserves headroom and dynamic range.

Intercom Systems

Alarm Sounders

Use Scenario: Two-way voice amplification in wired building intercom units requiring bidirectional analog signal handling.

IC Role / Device Role / Timing Role: Linear amplifier in both transmit and receive paths, often paired with KSB564A for complementary symmetry.

Use Value: Matched h_FE classification (Y/G) ensures consistent gain matching between NPN/PNP pairs, minimizing harmonic imbalance.

Use Scenario: High-reliability audible alert driver in fire alarm panels, security systems, and industrial annunciators.

IC Role / Device Role / Timing Role: Switch-mode audio driver toggling piezoelectric or electromagnetic sounders at 1–4 kHz.

Use Value: 130 MHz f_T and fast saturation behavior support clean square-wave drive up to 4 kHz without ringing or overshoot.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD47T1G	TO-220 package, higher P_C = 1.5 W, V_CEO = 40 V, same h_FE range	Requires PCB redesign for surface-mount or larger footprint; suited for higher-power or heatsinked applications	Select when >800 mW dissipation or improved thermal performance is required; not drop-in compatible
2N5551	Lower I_C = 600 mA, lower P_C = 625 mW, V_CEO = 160 V, f_T = 100 MHz	Better for high-voltage, low-current signal amplification; unsuitable for 1 A audio output loads	Choose only for preamplifier or voltage-amplifier stages-not for power output replacement

Compared with MJD47T1G and 2N5551, the KSD471AGTA uniquely balances 1 A current delivery, TO-92 through-hole compatibility, and audio-optimized gain-bandwidth in a cost-sensitive, space-constrained form factor - making it optimal for legacy and new low-power discrete amplifier designs where board real estate and assembly method are fixed constraints.

Availability

KSD471AGTA is available at Aetrix Electronics and suitable for portable audio amplifiers, TV speaker drivers, intercom systems, and alarm sounders requiring stable component supply and long-term manufacturing continuity.

Supply support for KSD471AGTA 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 logic solutions for automotive, industrial, cloud, and consumer markets.

The KSD471AGTA belongs to ON Semiconductor's legacy discrete transistor portfolio inherited from Fairchild, engineered specifically for cost-sensitive, high-volume audio power amplification and general-purpose linear switching applications.

FAQ

What is the pin configuration of the KSD471AGTA?

The KSD471AGTA uses a TO-92 package with a center-collector configuration: Pin 1 is Emitter, Pin 2 is Base, and Pin 3 is Collector. This arrangement is standardized per JEDEC TO-92 and matches the "-C" suffix designation in the part number. The KSD471AGTA pinout supports direct substitution in existing E-B-C layouts without rework, and its mechanical drawing is documented in Fairchild/ON Semiconductor Package Drawing TO92AM3.

Does the KSD471AGTA have a guaranteed minimum h_FE value?

Yes, the KSD471AGTA has two h_FE classifications: Y grade guarantees h_FE = 120–240, and G grade guarantees h_FE = 200–400, both measured at V_CE = 1 V and I_C = 100 mA. These bins are marked on the device body and ensure predictable base drive requirements in production audio amplifier designs using the KSD471AGTA.

Can the KSD471AGTA replace the KSD471A without changes?

Yes, the KSD471AGTA is a direct replacement for the legacy KSD471A. The "GTA" suffix denotes ON Semiconductor's post-Fairchild integration marking convention (replacing underscore with dash), but electrical specifications, package dimensions, pinout, and thermal ratings remain identical. No PCB or schematic modifications are needed when upgrading from KSD471A to KSD471AGTA.

What is the maximum safe operating temperature for the KSD471AGTA?

The KSD471AGTA has a maximum junction temperature (T_J) of 150 °C and a storage temperature range of –55 °C to +150 °C. For continuous operation, ambient temperature must be limited based on power dissipation and PCB thermal resistance; at 25 °C ambient, full 800 mW dissipation is allowed, with linear derating above that per the datasheet's thermal curve. Thermal design for the KSD471AGTA should assume no external heatsink unless required by system-level thermal modeling.

Is the KSD471AGTA suitable for switching applications?

The KSD471AGTA is characterized for linear amplification but can operate in switching mode with appropriate base drive and load conditions. Its V_CE(sat) = 0.5 V at I_C = 1 A and I_B = 0.1 A, and f_T = 130 MHz support clean turn-on/turn-off in audio-frequency switching (e.g., alarm tone generation). However, it is not optimized for high-speed digital switching; for >100 kHz PWM, dedicated switching transistors like MMBT4401 are preferred over the KSD471AGTA.

KSD471AGTA Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

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:: 200 @ 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

KSD471AGTA FAQ

1.How can I place an order for KSD471AGTA through Aetrix?

Please submit a Request for Quotation (RFQ) for KSD471AGTA 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 KSD471AGTA reliable?

The price and inventory of KSD471AGTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSD471AGTA is usually 5 days.

3.What payment methods are accepted for KSD471AGTA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSD471AGTA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSD471AGTA?

KSD471AGTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSD471AGTA 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 KSD471AGTA?

For technical support, including KSD471AGTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSD471AGTA requirements.

6.How does Aetrix verify that KSD471AGTA is sourced from the original manufacturer or authorized distributors?

All KSD471AGTA 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 KSD471AGTA meets industry standards.

7.What is the process for return or replacement of KSD471AGTA?

All KSD471AGTA units undergo pre-shipment inspection (PSI). If there is an issue with KSD471AGTA, 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 KSD471AGTA part is unused and in its original packaging.

Return procedure for KSD471AGTA:

1.Submit a request within 90 days.

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

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