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

onsemi BC817-25LT3H

Name: BC817-25LT3H
Brand: onsemi
SKU: BC817-25LT3H
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC817-25LT3H

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: BC817-25LT3H.pdf

Description:: TRANS NPN 45V 0.5A SOT23-3

Quantity:: RFQ Add To RFQ list

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Inventory:50,000

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Product details

Overview

BC817-25LT3H from onsemi is an NPN silicon general-purpose transistor in SOT-23 package, rated for 45 V V_CEO, 500 mA continuous collector current, and DC current gain (h_FE) of 160–400 at I_C = 100 mA / V_CE = 1 V. It serves as a low-voltage switching or linear amplification device in power management and signal interface circuits.

For engineers reviewing the BC817-25LT3H datasheet, pinout, applications, or equivalent options, key selection criteria include verified h_FE binning (25-series), SOT-23 thermal performance (R_JA = 556°C/W on FR-5), V_CE(sat) ≤ 0.7 V at I_C/I_B = 10, and Pb-free compliance per J-STD-609.

Technical Context

The BC817-25LT3H is a discrete bipolar junction transistor with fixed NPN polarity and no integrated biasing or protection circuitry. Its operation relies on external base drive control, with specified V_BE(on) ≤ 1.2 V at I_C = 500 mA and f_T = 100 MHz for small-signal amplification up to mid-VHF range.

Thermal design must account for two dissipation modes: 225 mW on FR-5 board (derating 1.8 mW/°C above 25°C) or 300 mW on alumina substrate (derating 2.4 mW/°C). Junction temperature is rated from −55°C to +150°C, supporting industrial ambient operation.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum allowable collector-emitter voltage before breakdown under open-base condition
I_C (continuous)	500 mA - Continuous collector current limit defining safe DC conduction capability
h_FE (min–max)	160–400 - Confirmed DC current gain range at I_C = 100 mA / V_CE = 1 V, used for base drive sizing
V_CE(sat)	≤ 0.7 V - Saturation voltage at I_C = 500 mA / I_B = 50 mA, directly impacts switch power loss
f_T	100 MHz - Transition frequency indicating usable bandwidth for small-signal amplification
R_JA (FR-5)	556 °C/W - Thermal resistance from junction to ambient on standard epoxy PCB, critical for thermal margin calculation
T_J range	−55°C to +150°C - Valid operating junction temperature span, enabling use in extended-temperature industrial designs

Pinout & Package

SOT-23 (Case 318, Style 6) surface-mount plastic package with gull-wing leads; dimensions: 2.90 mm × 1.30 mm × 1.00 mm (L × W × H); RoHS-compliant, Pb-free construction.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal accepting forward-biased current to enable conduction between collector and emitter
2	Emitter	Current return path; internally tied to substrate reference and used for grounding in common-emitter configurations
3	Collector	Primary output terminal sourcing current to load when transistor is biased active or saturated

Key Features

Feature	Design Value
DC current gain binning	h_FE = 160–400 (25-series) ensures predictable base drive requirements across production lots
Low saturation voltage	V_CE(sat) ≤ 0.7 V at rated I_C/I_B reduces conduction loss in switching applications
High f_T	100 MHz enables stable amplification up to VHF band without external compensation
Extended temperature rating	−55°C to +150°C junction range supports deployment in automotive engine compartments and industrial motor controls

Applications

LED Driver Circuits	Microcontroller GPIO Interface
Use Scenario: Driving 20–100 mA indicator or status LEDs from 3.3 V or 5 V logic rails. IC Role / Device Role / Timing Role: NPN switch controlling LED anode current path with microcontroller GPIO as base driver. Use Value: Verified V_CE(sat) ≤ 0.7 V ensures >90% efficiency at 50 mA load, minimizing heat rise in compact layouts.	Use Scenario: Level-shifting or current amplification between low-drive MCU pins and higher-current peripherals. IC Role / Device Role / Timing Role: Discrete buffer isolating MCU outputs from capacitive or resistive loads exceeding GPIO sink/source limits. Use Value: h_FE ≥ 160 allows reliable switching with ≤ 0.5 mA base drive, preserving MCU pin integrity.
Power Supply Enable Control	Relay Driver Stage
Use Scenario: Enabling/disabling secondary 3.3 V or 5 V LDOs or DC-DC converters via system controller signals. IC Role / Device Role / Timing Role: Low-side switch activating EN pin of regulator ICs with clean turn-on/turn-off transitions. Use Value: Fast f_T = 100 MHz ensures sub-microsecond edge response, preventing regulator brown-out during enable sequencing.	Use Scenario: Driving 5–24 V coil relays requiring 20–80 mA holding current in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Final-stage amplifier converting logic-level control into sufficient coil current with flyback diode integration. Use Value: 45 V V_CEO rating safely absorbs relay coil flyback transients up to 40 V without clamping components.

LED Driver Circuits

Microcontroller GPIO Interface

Use Scenario: Driving 20–100 mA indicator or status LEDs from 3.3 V or 5 V logic rails.

IC Role / Device Role / Timing Role: NPN switch controlling LED anode current path with microcontroller GPIO as base driver.

Use Value: Verified V_CE(sat) ≤ 0.7 V ensures >90% efficiency at 50 mA load, minimizing heat rise in compact layouts.

Use Scenario: Level-shifting or current amplification between low-drive MCU pins and higher-current peripherals.

IC Role / Device Role / Timing Role: Discrete buffer isolating MCU outputs from capacitive or resistive loads exceeding GPIO sink/source limits.

Use Value: h_FE ≥ 160 allows reliable switching with ≤ 0.5 mA base drive, preserving MCU pin integrity.

Power Supply Enable Control

Relay Driver Stage

Use Scenario: Enabling/disabling secondary 3.3 V or 5 V LDOs or DC-DC converters via system controller signals.

IC Role / Device Role / Timing Role: Low-side switch activating EN pin of regulator ICs with clean turn-on/turn-off transitions.

Use Value: Fast f_T = 100 MHz ensures sub-microsecond edge response, preventing regulator brown-out during enable sequencing.

Use Scenario: Driving 5–24 V coil relays requiring 20–80 mA holding current in industrial PLC I/O modules.

IC Role / Device Role / Timing Role: Final-stage amplifier converting logic-level control into sufficient coil current with flyback diode integration.

Use Value: 45 V V_CEO rating safely absorbs relay coil flyback transients up to 40 V without clamping components.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC817-25LT1	Same die, SOT-23 package, but supplied in 3,000-unit tape-and-reel vs. 10,000-unit reel for BC817-25LT3H	Identical electrical specs and pinout; differs only in packaging quantity and marking (6B vs. 6B with H suffix)	Select BC817-25LT1 for lower-volume prototyping or where smaller reels reduce inventory overhead
MMBT2222ALT1G	h_FE = 100–300 (lower max gain), V_CEO = 40 V, R_JA = 400°C/W on FR-5 - slightly better thermal resistance but reduced voltage margin	Compatible in low-voltage (<40 V) switching; not recommended where 45 V transient immunity or >300 h_FE is required	Choose MMBT2222ALT1G only if existing BOM uses it and layout accommodates identical SOT-23 footprint

Compared with BC817-25LT1, BC817-25LT3H offers identical performance in a higher-volume reel format; versus MMBT2222ALT1G, it provides +5 V higher V_CEO and +100 minimum h_FE, improving robustness in 24 V industrial systems and reducing base drive sensitivity.

Availability

BC817-25LT3H is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO interface, and power supply enable control requiring stable component supply, consistent h_FE binning, and Pb-free compliance.

Supply support for BC817-25LT3H 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 specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BC817 series belongs to onsemi's general-purpose bipolar transistor product line, designed for cost-sensitive, high-reliability discrete switching and amplification in space-constrained PCBs.

FAQ

What is the maximum collector-emitter voltage rating for BC817-25LT3H?

The BC817-25LT3H has a maximum collector-emitter voltage (V_CEO) rating of 45 V under open-base conditions. This value is confirmed in the Absolute Maximum Ratings table of the official onsemi datasheet (Rev. 9, March 2009) and defines the upper limit for safe DC or pulse operation without risk of avalanche breakdown. Exceeding this voltage may cause irreversible device failure.

Does BC817-25LT3H have Pb-free construction?

Yes, BC817-25LT3H is manufactured with Pb-free terminations and complies with J-STD-609. The "H" suffix in the part number denotes Pb-free packaging, and the datasheet explicitly states "Pb−Free Packages are Available" under Features. This makes BC817-25LT3H suitable for RoHS-compliant designs without requiring leaded solder alternatives.

What is the DC current gain (h_FE) range for BC817-25LT3H at typical operating conditions?

The BC817-25LT3H exhibits a DC current gain (h_FE) range of 160 to 400 when measured at I_C = 100 mA and V_CE = 1.0 V, per the Electrical Characteristics table. This binning (25-series) is tighter than the 16-series (100–250) and 40-series (250–600), offering improved predictability for base resistor selection in production designs.

Can BC817-25LT3H be used in linear amplification applications?

Yes, BC817-25LT3H supports linear amplification due to its f_T = 100 MHz and well-characterized small-signal parameters including C_obo = 10 pF. However, its primary design intent is switching; for precision analog gain stages, dedicated RF or low-noise transistors with tighter h_FE tolerance and lower noise figure are preferred. BC817-25LT3H remains viable for non-critical audio or sensor buffering where cost and footprint are prioritized.

What is the thermal resistance (R_JA) of BC817-25LT3H on a standard FR-5 PCB?

The thermal resistance from junction-to-ambient (R_JA) for BC817-25LT3H mounted on an FR-5 board is 556°C/W at T_A = 25°C, with a derating factor of 1.8 mW/°C above that temperature. This value is specified in the Thermal Characteristics section and is essential for calculating maximum allowable power dissipation under real-world board layouts and airflow conditions.

BC817-25LT3H Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Bulk

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 45 V

Vce Saturation (Max) @ Ib, Ic:: 700mV @ 50mA, 500mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 160 @ 100mA, 1V

Power - Max:: 300 mW

Frequency - Transition:: 100MHz

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3 (TO-236)

BC817-25LT3H FAQ

1.How can I place an order for BC817-25LT3H through Aetrix?

Please submit a Request for Quotation (RFQ) for BC817-25LT3H 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 BC817-25LT3H reliable?

The price and inventory of BC817-25LT3H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC817-25LT3H is usually 5 days.

3.What payment methods are accepted for BC817-25LT3H?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC817-25LT3H transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC817-25LT3H?

BC817-25LT3H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC817-25LT3H 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 BC817-25LT3H?

For technical support, including BC817-25LT3H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC817-25LT3H requirements.

6.How does Aetrix verify that BC817-25LT3H is sourced from the original manufacturer or authorized distributors?

All BC817-25LT3H 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 BC817-25LT3H meets industry standards.

7.What is the process for return or replacement of BC817-25LT3H?

All BC817-25LT3H units undergo pre-shipment inspection (PSI). If there is an issue with BC817-25LT3H, 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 BC817-25LT3H part is unused and in its original packaging.

Return procedure for BC817-25LT3H:

1.Submit a request within 90 days.

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

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