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

onsemi BC808-40LT1

Name: BC808-40LT1
Brand: onsemi
SKU: BC808-40LT1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC808-40LT1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC808-40LT1.pdf

Description:: TRANS PNP 25V 0.5A SOT23-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC808-40LT1 from onsemi is a PNP silicon general-purpose transistor in SOT-23 package, rated for −25 V V_CEO, −500 mA continuous collector current, and DC current gain (h_FE) of 250–600 at I_C = −100 mA / V_CE = −1.0 V. It serves as a low-voltage switching or linear amplification device in power management and signal routing circuits.

For engineers reviewing the BC808-40LT1 datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed h_FE ≥250 at −100 mA, V_CE(sat) ≤ −0.7 V at −500 mA/−50 mA drive, thermal resistance of 556 °C/W on FR-5 board, and Pb-free SOT-23 compatibility with automated assembly.

Technical Context

The BC808-40LT1 operates as a discrete PNP bipolar junction transistor optimized for medium-current switching and analog amplification. Its design supports stable DC current gain across I_C = −10 mA to −500 mA, with verified V_BE(on) ≤ −1.2 V and f_T = 100 MHz at −10 mA/−5 V.

It features a maximum junction temperature of +150°C, storage range from −55°C to +150°C, and thermal derating of 1.8 mW/°C above 25°C on FR-5 board - enabling reliable operation in compact industrial and consumer PCB layouts without forced cooling.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−25 V: Maximum safe collector-emitter voltage before breakdown under open-base conditions.
I_C (continuous)	−500 mA: Continuous collector current rating defining maximum steady-state load switching capability.
h_FE (min)	250 @ −100 mA/−1.0 V: Guaranteed DC current gain ensuring predictable base drive requirements in switch designs.
V_CE(sat)	≤ −0.7 V @ −500 mA/−50 mA: Low saturation voltage minimizes conduction loss in high-duty-cycle switching applications.
f_T	100 MHz: Transition frequency confirming usable bandwidth for audio-frequency amplification and fast digital switching.
R_JA (FR-5)	556 °C/W: Junction-to-ambient thermal resistance determining self-heating under 225 mW dissipation limit at 25°C.

Pinout & Package

SOT-23 (Case 318, Style 6) surface-mount package with 3-pin configuration: 1. Base, 2. Emitter, 3. Collector - footprint compatible with standard SOT-23 pick-and-place and reflow processes.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal for injecting minority-carrier current to modulate collector-emitter conduction.
2	Emitter	Current source terminal for PNP operation; connected to higher potential in typical common-emitter switch layout.
3	Collector	Output terminal sourcing current to load; reverse-biased relative to emitter during active/saturation operation.

Key Features

Feature	Design Value
Pb-free packaging	Complies with RoHS Directive 2011/65/EU; suitable for lead-free reflow soldering per J-STD-020.
Guaranteed h_FE binning	BC808-40LT1 specifically binned for h_FE ≥250 (−100 mA/−1.0 V), reducing base resistor tolerance sensitivity.
Low V_CE(sat)	≤ −0.7 V ensures <150 mW conduction loss at −500 mA, critical for thermally constrained PCBs.
High f_T	100 MHz enables stable operation up to ~10 MHz square-wave switching with minimal rise/fall time degradation.

Applications

LED Driver Circuit	Power Supply Enable Switch
Use Scenario: Driving 20–100 mA indicator or status LEDs from microcontroller GPIO pins. IC Role / Device Role / Timing Role: PNP switch controlling LED anode connection to regulated rail while sinking base current from MCU output. Use Value: Guaranteed h_FE ≥250 ensures full saturation with ≤2 mA base drive, minimizing GPIO loading and enabling direct interface with 3.3 V logic.	Use Scenario: Enabling/disabling downstream 3.3 V or 5 V LDO outputs in multi-rail power systems. IC Role / Device Role / Timing Role: High-side enable switch placed between input rail and LDO input, controlled by system supervisor or PMIC. Use Value: −25 V V_CEO and −500 mA rating support robust enable control across common supply rails without derating.
Level Translation Interface	Current Mirror Reference
Use Scenario: Translating 1.8 V logic signals to 5 V domains in mixed-voltage microcontroller peripherals. IC Role / Device Role / Timing Role: Common-emitter inverter stage providing inverted level shift with defined V_OH/V_OL thresholds. Use Value: 100 MHz f_T and low C_obo (10 pF) preserve signal integrity up to 5 MHz, supporting UART and SPI clock rates.	Use Scenario: Building matched current sources in analog sensor conditioning or bias networks. IC Role / Device Role / Timing Role: Active element in two-transistor current mirror topology, leveraging tight h_FE consistency within same production lot. Use Value: Binned h_FE (250–600) and low V_BE(on) variation (<±50 mV) improve mirror accuracy versus generic transistors.

LED Driver Circuit

Power Supply Enable Switch

Use Scenario: Driving 20–100 mA indicator or status LEDs from microcontroller GPIO pins.

IC Role / Device Role / Timing Role: PNP switch controlling LED anode connection to regulated rail while sinking base current from MCU output.

Use Value: Guaranteed h_FE ≥250 ensures full saturation with ≤2 mA base drive, minimizing GPIO loading and enabling direct interface with 3.3 V logic.

Use Scenario: Enabling/disabling downstream 3.3 V or 5 V LDO outputs in multi-rail power systems.

IC Role / Device Role / Timing Role: High-side enable switch placed between input rail and LDO input, controlled by system supervisor or PMIC.

Use Value: −25 V V_CEO and −500 mA rating support robust enable control across common supply rails without derating.

Level Translation Interface

Current Mirror Reference

Use Scenario: Translating 1.8 V logic signals to 5 V domains in mixed-voltage microcontroller peripherals.

IC Role / Device Role / Timing Role: Common-emitter inverter stage providing inverted level shift with defined V_OH/V_OL thresholds.

Use Value: 100 MHz f_T and low C_obo (10 pF) preserve signal integrity up to 5 MHz, supporting UART and SPI clock rates.

Use Scenario: Building matched current sources in analog sensor conditioning or bias networks.

IC Role / Device Role / Timing Role: Active element in two-transistor current mirror topology, leveraging tight h_FE consistency within same production lot.

Use Value: Binned h_FE (250–600) and low V_BE(on) variation (<±50 mV) improve mirror accuracy versus generic transistors.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP switching transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC807-40LT1	Same SOT-23 package, identical h_FE bin (250–600), but rated for −45 V V_CEO and −500 mA I_C.	Higher V_CEO allows use in 36 V automotive or industrial bus interfaces where BC808-40LT1's −25 V limit is insufficient.	Select BC807-40LT1 when operating above 25 V collector-emitter stress; otherwise, BC808-40LT1 offers optimal cost/performance at ≤25 V.
MMBT4403	Same PNP polarity and SOT-23 package, but h_FE = 100–300 (lower min), V_CEO = −40 V, V_CE(sat) = −0.75 V max.	Lower guaranteed h_FE requires larger base drive; higher V_CEO suits wider supply ranges, but reduced gain margin affects low-current switching.	Choose MMBT4403 only if −40 V rating is mandatory and base drive resources permit higher IB; BC808-40LT1 preferred for gain-critical 25 V designs.

Compared with BC808-40LT1, BC807-40LT1 extends voltage capability without sacrificing gain or package compatibility, while MMBT4403 trades guaranteed h_FE for broader voltage range - making BC808-40LT1 the optimal choice for cost-sensitive, ≤25 V, medium-gain PNP switching.

Availability

BC808-40LT1 is available at Aetrix Electronics and suitable for LED driver circuits, power supply enable switches, level translation interfaces, and current mirror references requiring stable component supply across industrial control, consumer electronics, and embedded instrumentation programs.

Supply support for BC808-40LT1 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 specializing in energy-efficient power, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and IoT applications.

The BC808-40LT1 belongs to onsemi's general-purpose bipolar transistor family designed for cost-effective, high-reliability discrete switching and amplification in space-constrained PCBs.

FAQ

What is the maximum collector-emitter voltage rating for BC808-40LT1?

The BC808-40LT1 has a maximum collector-emitter voltage (V_CEO) rating of −25 V. This value is specified under open-base conditions with I_C = −10 mA and defines the absolute upper limit before avalanche breakdown occurs. Exceeding this voltage risks permanent device damage, even momentarily. The BC808-40LT1 must not be used in circuits where V_CE could transiently exceed −25 V without clamping protection.

Does BC808-40LT1 support lead-free soldering processes?

Yes, BC808-40LT1 is offered in Pb-free packaging compliant with RoHS Directive 2011/65/EU. Its SOT-23 package is qualified for standard lead-free reflow profiles per J-STD-020, with peak temperatures up to 260°C. The device marking "5G" indicates Pb-free construction, and thermal performance data (e.g., R_JA = 556 °C/W) applies directly to Pb-free assembly conditions.

What is the guaranteed DC current gain (h_FE) range for BC808-40LT1?

The BC808-40LT1 is binned for h_FE ≥250 at I_C = −100 mA and V_CE = −1.0 V, with a maximum of 600 under the same conditions. At higher current (I_C = −500 mA), h_FE remains functional but is not guaranteed - design margins should rely on the −100 mA specification. This binning ensures consistent base drive requirements across production lots of BC808-40LT1.

Can BC808-40LT1 be used in high-frequency switching applications?

The BC808-40LT1 has an f_T of 100 MHz, indicating usable small-signal gain up to that frequency. For digital switching, it supports clean square-wave operation up to ~10 MHz due to stored charge and saturation delay limitations. Its C_obo of 10 pF and V_CE(sat) ≤ −0.7 V make it suitable for moderate-speed power switching, but not RF or >20 MHz clock distribution. Always verify switching waveforms empirically in the final BC808-40LT1 circuit.

What is the thermal resistance of BC808-40LT1 on a standard FR-5 PCB?

The BC808-40LT1 exhibits a junction-to-ambient thermal resistance (R_JA) of 556 °C/W when mounted on a 1.0 × 0.75 × 0.062 inch FR-5 board at T_A = 25°C. This value assumes no copper pour or thermal vias. Power dissipation must be derated by 1.8 mW/°C above 25°C ambient - meaning at 75°C ambient, the safe continuous power drops to 135 mW. Thermal performance of BC808-40LT1 improves significantly with added copper area.

BC808-40LT1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

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

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

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

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

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

Power - Max:: 300 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)

BC808-40LT1 FAQ

1.How can I place an order for BC808-40LT1 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC808-40LT1 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 BC808-40LT1 reliable?

The price and inventory of BC808-40LT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC808-40LT1 is usually 5 days.

3.What payment methods are accepted for BC808-40LT1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC808-40LT1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC808-40LT1?

BC808-40LT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC808-40LT1 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 BC808-40LT1?

For technical support, including BC808-40LT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC808-40LT1 requirements.

6.How does Aetrix verify that BC808-40LT1 is sourced from the original manufacturer or authorized distributors?

All BC808-40LT1 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 BC808-40LT1 meets industry standards.

7.What is the process for return or replacement of BC808-40LT1?

All BC808-40LT1 units undergo pre-shipment inspection (PSI). If there is an issue with BC808-40LT1, 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 BC808-40LT1 part is unused and in its original packaging.

Return procedure for BC808-40LT1:

1.Submit a request within 90 days.

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

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