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onsemi KSD261YBU
- Part No.:
- KSD261YBU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
KSD261YBU.pdf
- Description:
- TRANS NPN 20V 0.5A TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:6,334
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Product details
Overview
KSD261YBU from ON Semiconductor is an NPN epitaxial silicon transistor designed for low-frequency power amplifier applications, with a collector-emitter breakdown voltage of 20 V, DC current gain (hFE) ranging from 120 to 240 at IC = 0.1 A and VCE = 1 V, and a maximum collector power dissipation of 500 mW. It uses a TO-92 package with side-collector pinout (Emitter–Base–Collector) and operates up to 150°C junction temperature.
For engineers reviewing the KSD261YBU datasheet, pinout, applications, or equivalent options, key selection considerations include its hFE classification (Y-grade), VCE(sat) ≤ 0.40 V at IC = 0.5 A/IB = 50 mA, thermal resistance of 250°C/W, and suitability for linear amplification in consumer audio stages and relay drivers where moderate gain and robust SOA are required.
Technical Context
The KSD261YBU is a general-purpose bipolar junction transistor optimized for low-frequency analog amplification and switching. Its design emphasizes stable DC current gain across collector currents from 1 mA to 500 mA and low saturation voltage under moderate drive conditions.
It complements the PNP KSA643 in push-pull configurations and is specified with absolute maximum ratings including VCBO = 40 V, VCEO = 20 V, VEBO = 5 V, and IC = 500 mA - all validated at TA = 25°C with derating above that ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 20 V - Maximum safe collector-emitter voltage before breakdown; defines usable supply headroom in amplifier or switch designs. |
| hFE (Y-class) | 120–240 - Confirmed DC current gain range at VCE = 1 V, IC = 0.1 A; enables predictable biasing in Class-A amplifiers. |
| VCE(sat) | ≤ 0.40 V at IC = 0.5 A, IB = 50 mA - Ensures low conduction loss in saturated-switch applications like relay or LED drivers. |
| PC | 500 mW - Maximum continuous collector power dissipation; sets thermal design boundary for PCB copper area and ambient limits. |
| RθJA | 250°C/W - Junction-to-ambient thermal resistance on standard FR-4 board; requires ≥ 1 cm² copper pour for full-power operation at 25°C ambient. |
| ICBO | ≤ 0.1 μA at VCB = 25 V - Low collector leakage supports stable bias in high-impedance amplifier inputs and standby circuits. |
Pinout & Package
Package: TO-92, 3-lead molded plastic housing with side-collector configuration (Pin 1: Emitter, Pin 2: Base, Pin 3: Collector). Straight or bent lead options available per packing method.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Emitter | Current sink terminal; connects to ground or low-impedance return path in common-emitter amplifier or switch topologies. |
| 2 | Base | Control input; requires ~50 mA drive for full saturation at 500 mA collector current; base resistor sizing must account for hFE min = 120. |
| 3 | Collector | Current source terminal; connects to load (e.g., speaker coil, relay coil); voltage swing limited to ≤20 V peak-to-peak in linear use. |
Key Features
| Feature | Design Value |
|---|---|
| Low-frequency power amplification | Optimized for <1 MHz operation with stable hFE and low distortion in Class-A audio preamp stages. |
| Complementary pairing | Designed as NPN counterpart to KSA643 PNP transistor for symmetrical push-pull output stages. |
| TO-92 side-collector pinout | Standardized pin assignment (E-B-C) simplifies layout reuse across Fairchild/ON Semi low-power BJT families. |
| Y-grade hFE binning | Guaranteed 120–240 hFE range ensures consistent gain matching in production batches without manual sorting. |
Applications
| Audio Pre-amplifier Stage | DC Relay Driver |
|---|---|
Use Scenario: Amplifying line-level signals (≤1 Vpp) before power stage in portable radios or intercom systems. IC Role / Device Role / Timing Role: NPN common-emitter voltage amplifier with fixed bias or emitter-degenerated topology. Use Value: Delivers >20 dB voltage gain with <5% THD at 1 kHz due to stable hFE and low VCE(sat) enabling rail-efficient operation from 12 V supplies. | Use Scenario: Driving 12 V, 400 mW electromagnetic relays in industrial control panels. IC Role / Device Role / Timing Role: Saturated switch controlling relay coil current up to 33 mA. Use Value: Achieves <0.4 V saturation drop at 50 mA collector current, minimizing coil heating and ensuring reliable pull-in at marginal supply voltages. |
| LED Current Regulator | Signal-Level Shifter |
Use Scenario: Constant-current driving of high-brightness indicator LEDs in automotive dashboards. IC Role / Device Role / Timing Role: Linear current source with emitter resistor feedback. Use Value: Maintains ±5% LED current stability over temperature (−40°C to +85°C) using hFE-insensitive emitter degeneration. | Use Scenario: Level-shifting 3.3 V logic signals to interface with 5 V microcontroller peripherals. IC Role / Device Role / Timing Role: Common-emitter inverter with resistive pull-up. Use Value: Provides clean 0–5 V transitions with <100 ns propagation delay and no shoot-through risk due to single-BJT structure. |
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 |
|---|---|---|---|
| KSD261GTA | Same die, G-grade hFE (200–400), identical TO-92 package and pinout. | Higher gain enables lower base drive current; preferred in low-power battery-operated amplifiers. | Select KSD261GTA when tighter hFE tolerance or higher gain is needed; otherwise KSD261YBU offers cost-effective Y-bin performance. |
| MPSA13 | Lower PC = 350 mW, hFE = 50–250, same TO-92 package but different pinout (E-C-B). | Not pin-compatible; requires PCB redesign; suitable only for non-critical gain applications with reduced power demand. | Choose MPSA13 only if legacy design reuse mandates TO-92 footprint and gain variation is acceptable; verify pin mapping before substitution. |
Compared with KSD261GTA and MPSA13, the KSD261YBU provides balanced gain consistency (120–240), full 500 mW power capability, and verified side-collector pinout - making it optimal for cost-sensitive, medium-gain amplifier and driver designs requiring predictable thermal and electrical behavior.
Availability
KSD261YBU is available at Aetrix Electronics and suitable for audio pre-amplifier stages, DC relay drivers, and LED current regulators requiring stable component supply and consistent Y-grade hFE binning.
Supply support for KSD261YBU 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 and signal management solutions, with roots in Fairchild Semiconductor's discrete transistor legacy.
The KSD261YBU belongs to ON Semiconductor's general-purpose bipolar transistor product line, engineered for reliability and consistency in low-frequency linear and switching applications across consumer, industrial, and computing markets.
FAQ
What is the pin configuration of the KSD261YBU?
The KSD261YBU uses a TO-92 package with side-collector pinout: Pin 1 is Emitter, Pin 2 is Base, and Pin 3 is Collector. This configuration differs from center-collector variants (e.g., KSD261C) and must be verified against PCB footprints. The KSD261YBU datasheet confirms this arrangement for all non-suffix and "YBU" marked units.
What does the "Y" in KSD261YBU signify?
The "Y" suffix in KSD261YBU denotes the hFE bin classification: guaranteed DC current gain between 120 and 240 at VCE = 1 V and IC = 0.1 A. This binning ensures predictable biasing in production designs without manual gain sorting. The "BU" suffix indicates tape-and-reel packaging per ON Semiconductor's post-Fairchild nomenclature standard.
Can KSD261YBU replace KSD261GTA in an existing design?
Yes, the KSD261YBU can replace KSD261GTA electrically and mechanically - both share identical TO-92 package, pinout, and absolute maximum ratings. However, the KSD261GTA has higher hFE (200–400), so bias networks may require minor adjustment to maintain operating point. The KSD261YBU remains fully functional as a direct drop-in where Y-bin gain suffices.
What is the maximum safe operating collector current for KSD261YBU?
The KSD261YBU supports a maximum continuous collector current of 500 mA at TA = 25°C, with linear derating above that ambient. At 75°C ambient, the usable IC drops to approximately 300 mA due to thermal limits. Operation beyond 500 mA risks secondary breakdown or accelerated degradation, even with heatsinking - always verify SOA curves in the KSD261YBU datasheet for pulsed conditions.
Is KSD261YBU suitable for switching power supply applications?
No, the KSD261YBU is not recommended for switching power supply applications. Its fT is unspecified and typically <10 MHz, and it lacks optimized switching characteristics such as fast turn-off, low storage time, or rugged SOA for hard-switching. The KSD261YBU is explicitly characterized for low-frequency power amplification and linear switching - use dedicated power MOSFETs or high-speed BJTs like MMBT2222A for SMPS designs.
KSD261YBU 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):
- 500 mA
- Voltage - Collector Emitter Breakdown (Max):
- 20 V
- Vce Saturation (Max) @ Ib, Ic:
- 400mV @ 50mA, 500mA
- Current - Collector Cutoff (Max):
- 100nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 120 @ 100mA, 1V
- Power - Max:
- 500 mW
- Frequency - Transition:
- -
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
KSD261YBU FAQ
1.How can I place an order for KSD261YBU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSD261YBU 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 KSD261YBU reliable?
The price and inventory of KSD261YBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSD261YBU is usually 5 days.
3.What payment methods are accepted for KSD261YBU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSD261YBU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSD261YBU?
KSD261YBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSD261YBU 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 KSD261YBU?
For technical support, including KSD261YBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSD261YBU requirements.
6.How does Aetrix verify that KSD261YBU is sourced from the original manufacturer or authorized distributors?
All KSD261YBU 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 KSD261YBU meets industry standards.
7.What is the process for return or replacement of KSD261YBU?
All KSD261YBU units undergo pre-shipment inspection (PSI). If there is an issue with KSD261YBU, 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 KSD261YBU part is unused and in its original packaging.
Return procedure for KSD261YBU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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