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

onsemi BC817-40LT1

Name: BC817-40LT1
Brand: onsemi
SKU: BC817-40LT1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC817-40LT1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC817-40LT1.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC817-40LT1 from onsemi is an NPN silicon general-purpose transistor in SOT-23 package, rated for 45 V V_CEO, 500 mA I_C, and DC current gain (h_FE) of 250–600 at I_C = 500 mA / V_CE = 1.0 V. It delivers low V_CE(sat) ≤ 0.7 V and f_T ≥ 100 MHz, enabling use in compact DC-DC converter switching stages and microcontroller-driven load interfaces.

For engineers reviewing the BC817-40LT1 datasheet, pinout, applications, or equivalent options, key selection criteria include verified h_FE range at high I_C, thermal resistance (R_JA = 556 °C/W on FR-5), and AEC-Q101 qualification for automotive signal conditioning circuits.

Technical Context

This discrete NPN transistor operates in linear or saturated switching mode with base-emitter turn-on voltage V_BE(on) ≤ 1.2 V at I_C = 500 mA and exhibits fast switching performance: t_r ≤ 30 ns, t_f ≤ 300 ns under defined test conditions (V_CC = 3.0 V, I_C = 10 mA).

Its safe operating area supports single-pulse I_C up to 0.7 A at V_CE = 10 V, constrained by thermal limits (T_J = −65 to +150 °C) and junction-to-ambient resistance of 556 °C/W on standard FR-5 board - critical for thermally constrained PCB layouts.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum collector-emitter blocking voltage before breakdown; defines usable supply rail headroom in low-voltage switching.
I_C (continuous)	500 mA - Continuous collector current rating; sets upper limit for sustained load drive without derating.
h_FE @ I_C=500 mA	250–600 - High DC current gain range enables low-base-drive designs; reduces MCU GPIO current burden.
V_CE(sat) @ I_C=500 mA	≤ 0.7 V - Low saturation voltage minimizes conduction loss and self-heating in switching applications.
f_T	≥ 100 MHz - Current-gain bandwidth product supports reliable operation up to high-frequency switching (e.g., >100 kHz PWM).
R_JA (FR-5)	556 °C/W - Thermal resistance determines required board copper area and airflow for thermal management.
AEC-Q101 Qualified	Yes - Validated for automotive-grade reliability including temperature cycling, humidity, and mechanical stress testing.

Pinout & Package

SOT-23 (Case 318, Style 6) surface-mount package with 3-pin configuration: Collector (Pin 1), Base (Pin 2), Emitter (Pin 3). Marking "6C" identifies BC817-40L variant per onsemi datasheet page 2.

Pin/Terminal	Circuit Role	Design Meaning
1	Collector	Main current output terminal; connects to load or higher potential node in common-emitter switch topology.
2	Base	Control input; requires current-limited drive (e.g., series resistor) to bias into active/saturation region.
3	Emitter	Current return path; typically tied to ground or low-side reference in switching configurations.

Key Features

Feature	Design Value
Pb-free, RoHS-compliant	Meets global environmental regulations; eliminates lead-based solder compatibility concerns in modern assembly lines.
AEC-Q101 qualified	Validated for automotive electronics including engine control modules and body electronics requiring extended temperature and lifetime reliability.
High h_FE bin (250–600)	Reduces required base drive current by up to 2× versus lower-gain variants (e.g., BC817-16), easing microcontroller GPIO sourcing.
Low V_CE(sat) ≤ 0.7 V	Minimizes power dissipation (P = I_C × V_CE(sat)) during on-state, improving efficiency in battery-powered load switches.
Fast switching (t_r/t_f ≤ 30/300 ns)	Enables clean digital edge transitions in PWM-driven solenoids, relays, and LED drivers without excessive ringing.

Applications

Automotive Body Control Module	Industrial PLC Output Stage
Use Scenario: Driving 12 V solenoid valves and indicator LEDs in vehicle door lock and lighting subsystems. IC Role / Device Role / Timing Role: NPN switch providing low-side current sink with controlled turn-on/turn-off timing. Use Value: AEC-Q101 qualification ensures operation across −40 to +125 °C ambient; h_FE ≥ 250 allows direct MCU GPIO drive without external buffer.	Use Scenario: Isolating and amplifying digital outputs from programmable logic controllers to 24 V industrial actuators. IC Role / Device Role / Timing Role: Discrete transistor used as level-shifting interface between 3.3/5 V logic and 24 V field-side loads. Use Value: V_CEO = 45 V provides 20 V margin above 24 V nominal rail; R_JA = 556 °C/W enables thermal stability on standard FR-4 PCBs.
Consumer Appliance Motor Driver	IoT Sensor Node Load Switch
Use Scenario: Controlling small brushed DC motors in smart home appliances (e.g., coffee grinders, air purifiers). IC Role / Device Role / Timing Role: Saturated switch in common-emitter configuration, driven by PWM from MCU. Use Value: f_T ≥ 100 MHz supports clean 20 kHz PWM switching; V_CE(sat) ≤ 0.7 V keeps motor driver stage losses below 350 mW at 500 mA.	Use Scenario: Enabling/disabling power to peripheral sensors (e.g., gas, humidity) in battery-operated IoT nodes. IC Role / Device Role / Timing Role: Low-leakage load switch with <100 nA I_CBO ensuring minimal standby current drain. Use Value: T_stg = −65 to +150 °C supports wide deployment environments; SOT-23 footprint saves space in ultra-compact sensor modules.

Automotive Body Control Module

Industrial PLC Output Stage

Use Scenario: Driving 12 V solenoid valves and indicator LEDs in vehicle door lock and lighting subsystems.

IC Role / Device Role / Timing Role: NPN switch providing low-side current sink with controlled turn-on/turn-off timing.

Use Value: AEC-Q101 qualification ensures operation across −40 to +125 °C ambient; h_FE ≥ 250 allows direct MCU GPIO drive without external buffer.

Use Scenario: Isolating and amplifying digital outputs from programmable logic controllers to 24 V industrial actuators.

IC Role / Device Role / Timing Role: Discrete transistor used as level-shifting interface between 3.3/5 V logic and 24 V field-side loads.

Use Value: V_CEO = 45 V provides 20 V margin above 24 V nominal rail; R_JA = 556 °C/W enables thermal stability on standard FR-4 PCBs.

Consumer Appliance Motor Driver

IoT Sensor Node Load Switch

Use Scenario: Controlling small brushed DC motors in smart home appliances (e.g., coffee grinders, air purifiers).

IC Role / Device Role / Timing Role: Saturated switch in common-emitter configuration, driven by PWM from MCU.

Use Value: f_T ≥ 100 MHz supports clean 20 kHz PWM switching; V_CE(sat) ≤ 0.7 V keeps motor driver stage losses below 350 mW at 500 mA.

Use Scenario: Enabling/disabling power to peripheral sensors (e.g., gas, humidity) in battery-operated IoT nodes.

IC Role / Device Role / Timing Role: Low-leakage load switch with <100 nA I_CBO ensuring minimal standby current drain.

Use Value: T_stg = −65 to +150 °C supports wide deployment environments; SOT-23 footprint saves space in ultra-compact sensor modules.

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
BC847C,215 (Nexperia)	Lower I_C rating (100 mA), h_FE = 420–800 @ I_C = 10 mA, but only 110–220 @ I_C = 100 mA; V_CEO = 45 V same.	Not suitable for 500 mA continuous loads; better for low-current signal amplification than power switching.	Select BC847C only if load current remains ≤100 mA and higher h_FE at low I_C is prioritized over saturation performance.
MMBT4401LT1G (onsemi)	Higher V_CEO = 40 V (vs. 45 V), same I_C = 600 mA, h_FE = 100–300 @ I_C = 150 mA; V_CE(sat) = 0.75 V @ I_C = 500 mA.	Marginally lower voltage rating and reduced h_FE at high current; slightly higher saturation loss.	MMBT4401LT1G offers comparable robustness but BC817-40LT1 delivers superior h_FE and lower V_CE(sat) for 500 mA switching.

Compared with BC847C and MMBT4401LT1G, BC817-40LT1 uniquely combines 45 V V_CEO, 500 mA I_C, and h_FE ≥ 250 at full rated current - making it optimal for medium-power automotive and industrial switching where gain consistency matters.

Availability

BC817-40LT1 is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC output stages, and consumer appliance motor drivers requiring stable component supply and long-term lifecycle support.

Supply support for BC817-40LT1 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, with leadership in automotive, industrial, cloud, and IoT power and sensing solutions.

The BC817 series belongs to onsemi's general-purpose bipolar transistor portfolio, designed specifically for cost-sensitive, high-reliability switching and amplification in automotive and industrial control systems.

FAQ

What is the maximum continuous collector current rating for BC817-40LT1?

The BC817-40LT1 has a maximum continuous collector current (I_C) rating of 500 mA at T_A = 25 °C. Derating applies above 25 °C per the thermal characteristics table: 1.8 mW/°C on FR-5 board. This rating is confirmed in the "MAXIMUM RATINGS" section of the official onsemi datasheet (Rev. 18, November 2022).

Is BC817-40LT1 AEC-Q101 qualified and what does that mean for automotive use?

Yes, BC817-40LT1 is AEC-Q101 qualified and PPAP capable, as stated in the "Features" section of the onsemi datasheet. This means the device has passed rigorous stress tests for temperature cycling, humidity, mechanical shock, and electrical reliability - validating its suitability for non-safety-critical automotive applications such as body electronics and infotainment peripherals.

What is the DC current gain (h_FE) range for BC817-40LT1 at 500 mA collector current?

Per the "ELECTRICAL CHARACTERISTICS" table, BC817-40LT1 exhibits h_FE = 250 (min), – (typ), 600 (max) at I_C = 500 mA and V_CE = 1.0 V. This high-gain bin distinguishes it from BC817-16LT1 (h_FE = 100–250) and BC817-25LT1 (h_FE = 160–400), enabling lower base drive requirements.

What package type and marking code does BC817-40LT1 use?

BC817-40LT1 uses the SOT-23 package (Case 318, Style 6) with standardized pinout: Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter. Its top-side marking is "6C", as documented in the "ORDERING INFORMATION" and "MARKING DIAGRAM" sections of the onsemi datasheet.

How does the thermal resistance of BC817-40LT1 affect PCB layout design?

BC817-40LT1 has R_JA = 556 °C/W on FR-5 board (1.0 × 0.75 × 0.062 in), meaning each watt of dissipated power raises junction temperature by 556 °C above ambient. To maintain T_J ≤ 150 °C at 500 mA and V_CE(sat) = 0.7 V (P ≈ 350 mW), designers must ensure adequate copper pour and avoid thermal isolation - especially in compact automotive modules.

BC817-40LT1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Cut Tape (CT)

Product Status:: Obsolete

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):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: 250 @ 100mA, 1V

Power - Max:: 225 mW

Frequency - Transition:: 100MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

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

BC817-40LT1 FAQ

1.How can I place an order for BC817-40LT1 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC817-40LT1 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 BC817-40LT1 reliable?

The price and inventory of BC817-40LT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC817-40LT1 is usually 5 days.

3.What payment methods are accepted for BC817-40LT1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC817-40LT1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC817-40LT1?

BC817-40LT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC817-40LT1 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 BC817-40LT1?

For technical support, including BC817-40LT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC817-40LT1 requirements.

6.How does Aetrix verify that BC817-40LT1 is sourced from the original manufacturer or authorized distributors?

All BC817-40LT1 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 BC817-40LT1 meets industry standards.

7.What is the process for return or replacement of BC817-40LT1?

All BC817-40LT1 units undergo pre-shipment inspection (PSI). If there is an issue with BC817-40LT1, 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 BC817-40LT1 part is unused and in its original packaging.

Return procedure for BC817-40LT1:

1.Submit a request within 90 days.

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

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