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

onsemi KSD227GBU

Name: KSD227GBU
Brand: onsemi
SKU: KSD227GBU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSD227GBU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KSD227GBU.pdf

Description:: TRANS NPN 25V 0.3A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSD227GBU from Fairchild Semiconductor is an NPN epitaxial silicon transistor designed for low-frequency power amplifier applications, with V_CEO = 25 V, I_C = 300 mA, P_C = 400 mW, h_FE = 70–400 (depending on classification), and TO-92 package - used in audio preamplifier stages and relay driver circuits.

For engineers reviewing the KSD227GBU datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain range, saturation voltage at rated I_C, breakdown voltage margins, thermal derating behavior, and complementary pairing with KSA642 for push-pull configurations.

Technical Context

The KSD227GBU operates as a general-purpose bipolar junction transistor optimized for linear amplification below 100 kHz, featuring a maximum f_T of 100 MHz at I_C = 10 mA but specified for low-frequency power use. Its h_FE classification (O/Y/G) defines gain bins across production lots, enabling consistent biasing in fixed-gain amplifier designs.

It exhibits V_CE(sat) ≤ 0.4 V at I_C = 300 mA / I_B = 30 mA, supporting efficient switching in driver roles, while BVCBO = 30 V and TJ = 150 °C ensure robustness in thermally constrained PCB layouts with minimal heatsinking.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	25 V - Maximum safe collector-emitter voltage before avalanche; sets upper rail limit in Class-A amplifier stages.
I_C	300 mA - Continuous collector current rating; defines load-driving capability in relay or small-solenoid interfaces.
P_C	400 mW - Max dissipation at T_A = 25 °C; requires derating above 25 °C per 5.3 mW/°C slope.
h_FE	70–400 - Gain binning enables predictable DC bias point setting without individual device trimming.
V_CE(sat)	0.14–0.4 V - Low saturation voltage ensures <120 mW loss at full I_C, minimizing self-heating in switching mode.
T_J	150 °C - Junction temperature limit; allows operation in ambient up to 100 °C with appropriate PCB copper area.

Pinout & Package

Package: TO-92 - 3-lead through-hole plastic package with standard lead spacing (1.27 mm pitch), body height ≤ 3.86 mm, and JEDEC registered outline for manual or wave solder compatibility.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Reference node for base bias network; connects to ground or low-impedance return path in common-emitter amps.
2 (Base)	Control input	Receives current-limited drive signal; requires series resistor to set I_B for desired I_C based on h_FE bin.
3 (Collector)	Current source terminal	Connects to load (e.g., speaker coil or relay coil); polarity must match NPN configuration (positive supply referenced).

Key Features

Feature	Design Value
Complementary pairing	Designed as NPN counterpart to KSA642 PNP transistor, enabling matched push-pull output stages with symmetric gain and saturation behavior.
Low V_CE(sat)	0.14 V typical at I_C/I_B = 300 mA/30 mA - reduces conduction loss and improves efficiency in discrete switch-mode drivers.
Gain binning (O/Y/G)	Three h_FE ranges (70–140 / 120–240 / 200–400) allow selective sorting for stable bias design without feedback trimming.
High BV_CBO	30 V - Provides 20% margin over V_CEO, enhancing reliability during transient voltage events in inductive load switching.

Applications

Audio Preamp Stage	Relay Driver Circuit
Use Scenario: Amplifying line-level signals (≤1 V_pp) before feeding into power amplifier ICs in consumer audio equipment. IC Role / Device Role / Timing Role: NPN transconductance amplifier operating in common-emitter configuration with emitter degeneration resistor. Use Value: h_FE ≥ 70 ensures sufficient open-loop gain for fixed-bias designs; 400 mW P_C supports continuous 100 mW output without thermal runaway.	Use Scenario: Driving 12 V, 100 mA coil relays in industrial control panels where microcontroller GPIOs lack direct drive capability. IC Role / Device Role / Timing Role: Saturated switch controlling relay coil current; base driven by 3.3 V or 5 V logic via current-limiting resistor. Use Value: V_CE(sat) ≤ 0.4 V limits power loss to <40 mW, preventing thermal stress during sustained ON periods.
DC Motor Speed Control	LED Array Driver
Use Scenario: Linear speed regulation of small 6–12 V brushed DC motors in instrumentation or lab equipment using analog voltage input. IC Role / Device Role / Timing Role: Variable-current source in emitter-follower configuration, dissipating heat proportional to speed setting. Use Value: T_J = 150 °C and P_C = 400 mW enable stable operation at 200–300 mW dissipation with minimal heatsink area.	Use Scenario: Constant-current driving of 3–5 white LEDs in series (V_F ≈ 9–15 V) from a 15 V supply in signage or indicator modules. IC Role / Device Role / Timing Role: Current-regulating pass element in adjustable constant-current sink topology with sense resistor feedback. Use Value: BVCBO = 30 V provides headroom above LED string voltage, ensuring safe operation during supply ripple or turn-on transients.

Audio Preamp Stage

Relay Driver Circuit

Use Scenario: Amplifying line-level signals (≤1 V_pp) before feeding into power amplifier ICs in consumer audio equipment.

IC Role / Device Role / Timing Role: NPN transconductance amplifier operating in common-emitter configuration with emitter degeneration resistor.

Use Value: h_FE ≥ 70 ensures sufficient open-loop gain for fixed-bias designs; 400 mW P_C supports continuous 100 mW output without thermal runaway.

Use Scenario: Driving 12 V, 100 mA coil relays in industrial control panels where microcontroller GPIOs lack direct drive capability.

IC Role / Device Role / Timing Role: Saturated switch controlling relay coil current; base driven by 3.3 V or 5 V logic via current-limiting resistor.

Use Value: V_CE(sat) ≤ 0.4 V limits power loss to <40 mW, preventing thermal stress during sustained ON periods.

DC Motor Speed Control

LED Array Driver

Use Scenario: Linear speed regulation of small 6–12 V brushed DC motors in instrumentation or lab equipment using analog voltage input.

IC Role / Device Role / Timing Role: Variable-current source in emitter-follower configuration, dissipating heat proportional to speed setting.

Use Value: T_J = 150 °C and P_C = 400 mW enable stable operation at 200–300 mW dissipation with minimal heatsink area.

Use Scenario: Constant-current driving of 3–5 white LEDs in series (V_F ≈ 9–15 V) from a 15 V supply in signage or indicator modules.

IC Role / Device Role / Timing Role: Current-regulating pass element in adjustable constant-current sink topology with sense resistor feedback.

Use Value: BVCBO = 30 V provides headroom above LED string voltage, ensuring safe operation during supply ripple or turn-on transients.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN low-frequency power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC547C	Lower I_C (100 mA), lower P_C (500 mW but derated), h_FE = 420–800 - higher gain but lower current handling.	Suitable only for signal amplification or low-current switching; not recommended for 300 mA loads.	Select BC547C only when gain consistency > current capacity, and thermal load < 150 mW.
MPSA13	Higher h_FE (50–250), same TO-92, but V_CEO = 30 V and P_C = 625 mW - broader gain range and higher power rating.	Better suited for high-gain Darlington pre-stages or higher-power switching where 300 mA margin is insufficient.	Choose MPSA13 when designing for >300 mA peak loads or requiring guaranteed h_FE > 200 at low I_C.

Compared with BC547C and MPSA13, the KSD227GBU delivers optimal balance of 300 mA current drive, 400 mW dissipation, and binned h_FE for repeatable biasing - making it preferred for cost-sensitive, medium-power linear and switching applications where gain predictability matters more than ultra-high h_FE.

Availability

KSD227GBU is available at Aetrix Electronics and suitable for audio preamplifier stages, relay driver circuits, and DC motor speed control applications requiring stable component supply and long-term obsolescence management.

Supply support for KSD227GBU 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 KSD227GBU belongs to Fairchild's legacy general-purpose bipolar transistor family, engineered for cost-effective, reliable performance in low-frequency linear and switching applications across consumer, industrial, and automotive auxiliary systems.

FAQ

What is the maximum collector current rating for the KSD227GBU?

The KSD227GBU has a maximum continuous collector current (I_C) rating of 300 mA at T_A = 25 °C. This rating decreases with rising ambient temperature due to thermal derating - approximately 5.3 mW/°C reduction in allowable power dissipation above 25 °C. The KSD227GBU must be operated within this limit to avoid junction overheating and parametric shift.

Is the KSD227GBU pin-compatible with the KSA642?

No, the KSD227GBU is not pin-compatible with the KSA642. While they are complementary NPN/PNP pairs intended for push-pull use, the KSA642 uses the same TO-92 package but with reversed pinout: Emitter-Base-Collector vs. Emitter-Base-Collector for KSD227GBU. Physical layout verification is required before substitution; the KSD227GBU pin order is 1–Emitter, 2–Base, 3–Collector.

What does the 'G' suffix in KSD227GBU indicate?

The 'G' in KSD227GBU denotes the h_FE gain bin - specifically the highest gain group (200–400) per Fairchild's classification table. The 'BU' suffix indicates tape-and-reel packaging (bulk unpackaged version is KSD227B). This binning allows designers to select KSD227GBU when tight DC bias control and high forward gain are required without external feedback.

Can the KSD227GBU be used in switching applications?

Yes, the KSD227GBU is suitable for low-speed switching applications such as relay or LED array control, provided V_CE(sat) ≤ 0.4 V and switching frequency remains below 10 kHz. Its f_T is rated up to 100 MHz, but practical switching performance is limited by stored charge and minority carrier lifetime - verified in typical characteristics Figure 6. For PWM-driven loads, ensure base drive current exceeds 10% of I_C to achieve full saturation and minimize transition time losses in the KSD227GBU.

What is the junction-to-ambient thermal resistance (R_θJA) of the KSD227GBU?

The KSD227GBU has a typical junction-to-ambient thermal resistance (R_θJA) of 312.5 °C/W when mounted on a standard FR-4 PCB with minimal copper area (JEDEC 51-3 condition). This value improves significantly with added copper pour - e.g., 1 in² of 2-oz copper reduces R_θJA to ~120 °C/W. The KSD227GBU's 150 °C maximum junction temperature must be respected under all operating conditions, including worst-case ambient and power dissipation.

KSD227GBU 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):: 300 mA

Voltage - Collector Emitter Breakdown (Max):: 25 V

Vce Saturation (Max) @ Ib, Ic:: 400mV @ 30mA, 300mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 50mA, 1V

Power - Max:: 400 mW

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

KSD227GBU FAQ

1.How can I place an order for KSD227GBU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSD227GBU 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 KSD227GBU reliable?

The price and inventory of KSD227GBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSD227GBU is usually 5 days.

3.What payment methods are accepted for KSD227GBU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSD227GBU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSD227GBU?

KSD227GBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSD227GBU 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 KSD227GBU?

For technical support, including KSD227GBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSD227GBU requirements.

6.How does Aetrix verify that KSD227GBU is sourced from the original manufacturer or authorized distributors?

All KSD227GBU 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 KSD227GBU meets industry standards.

7.What is the process for return or replacement of KSD227GBU?

All KSD227GBU units undergo pre-shipment inspection (PSI). If there is an issue with KSD227GBU, 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 KSD227GBU part is unused and in its original packaging.

Return procedure for KSD227GBU:

1.Submit a request within 90 days.

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

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