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

onsemi BC640TF

Name: BC640TF
Brand: onsemi
SKU: BC640TF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC640TF

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC640TF.pdf

Description:: TRANS PNP 80V 1A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC640TF from ON Semiconductor (formerly Fairchild) is a PNP epitaxial silicon transistor designed for medium-power switching and linear amplifier applications. It features V_CEO = −80 V, I_C = −1 A, P_C = 1 W, h_FE = 25–160 (at I_C = −5 mA to −500 mA), and f_T = 100 MHz - enabling use in relay drivers, LED dimmers, and audio preamplifier stages.

For engineers reviewing the BC640TF datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-92 package compatibility, complementary pairing with BC639, guaranteed h_FE range across collector current, V_CE(sat) ≤ −0.5 V at I_C = −500 mA / I_B = −50 mA, and −150°C to +150°C operating junction temperature capability.

Technical Context

The BC640TF operates as a general-purpose PNP bipolar junction transistor with fixed-emitter configuration and base-controlled current amplification. Its epitaxial silicon construction ensures stable gain and low leakage (I_CBO ≤ −0.1 μA at V_CB = −30 V), while the −80 V V_CEO rating supports operation in 24 V and 48 V industrial control rails.

It is electrically identical to the BC640 series and shares the same DC current gain profile across three test points (h_FE1, h_FE2, h_FE3) and saturation characteristics (V_CE(sat), V_BE(on)) - confirming consistent behavior in both switching and analog biasing topologies without re-characterization.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−80 V: Maximum safe collector-emitter voltage before breakdown under open-base condition; enables use in 48 V supply systems with margin.
I_C	−1 A: Continuous collector current rating; supports driving loads up to ~1 W at moderate voltage swing.
P_C	1 W: Total power dissipation at T_A = 25°C; requires heatsinking above ~400 mW in enclosed environments.
h_FE	25–160: DC current gain range across I_C = −5 mA to −500 mA; ensures predictable base drive sizing in switch and amplifier designs.
f_T	100 MHz: Current-gain bandwidth product at V_CE = −5 V, I_C = −10 mA; suitable for audio-frequency amplification and fast-switching (<100 ns rise/fall) applications.
V_CE(sat)	−0.5 V max at I_C = −500 mA / I_B = −50 mA: Low saturation voltage minimizes conduction loss in high-current switching circuits.

Pinout & Package

BC640TF is housed in a standard TO-92 plastic package with 3 leads, lead-free and RoHS-compliant per manufacturer specification. Pin identification follows JEDEC TO-92 outline: viewed from flat side with leads down, left-to-right is Emitter–Collector–Base.

Pin/Terminal	Circuit Role	Design Meaning
1 (Left)	Emitter	Current exit terminal; connected to higher potential in PNP operation; provides reference for base-emitter biasing.
2 (Center)	Collector	Current entry terminal; tied to load or supply rail; handles full switched current and power dissipation.
3 (Right)	Base	Control input; negative current injection turns device on; requires current-limiting resistor for safe drive.

Key Features

Feature	Design Value
Complementary Pairing	Designed as direct PNP complement to NPN BC639 - enables matched push-pull output stages and differential amplifiers.
Low Saturation Voltage	V_CE(sat) ≤ −0.5 V at rated I_C/I_B - reduces power loss and thermal stress in saturated-switch applications.
Wide h_FE Range	Guaranteed h_FE = 25–160 across three collector current points - simplifies base resistor selection for diverse load conditions.
High f_T	100 MHz gain-bandwidth product - supports stable small-signal amplification up to mid-audio frequencies without external compensation.

Applications

Relay Driver Circuit	DC Motor Speed Control
Use Scenario: Driving 12 V/24 V electromagnetic relays in PLC I/O modules and industrial control panels. IC Role / Device Role / Timing Role: PNP switch controlling relay coil current path; base driven by microcontroller GPIO through current-limiting resistor. Use Value: V_CEO = −80 V provides 3× safety margin over 24 V rail; I_C = −1 A accommodates typical relay coils (≤700 mA); low V_CE(sat) limits self-heating during continuous hold.	Use Scenario: Controlling brushed DC motor direction and speed in battery-powered tools and HVAC actuators. IC Role / Device Role / Timing Role: High-side switch in H-bridge half-bridge stage or single-direction PWM driver. Use Value: TO-92 package allows compact layout; h_FE consistency across I_C enables predictable base drive scaling; f_T > 10 MHz supports PWM frequencies up to 20 kHz without gain roll-off.
Audio Preamp Stage	LED Constant-Current Dimmer
Use Scenario: Low-noise, low-distortion voltage amplifier in microphone preamplifiers and sensor signal conditioning circuits. IC Role / Device Role / Timing Role: Common-emitter linear amplifier with emitter degeneration resistor for stability and gain control. Use Value: f_T = 100 MHz ensures flat response to 20 kHz; low I_CBO (≤ −0.1 μA) minimizes input offset drift; V_BE(on) = −1 V enables precise bias point setting.	Use Scenario: Regulating current through high-brightness LEDs in signage and automotive interior lighting. IC Role / Device Role / Timing Role: Adjustable constant-current sink using emitter-follower configuration with sense resistor feedback. Use Value: P_C = 1 W supports ≥500 mA LED strings at 2 V drop; V_CEO = −80 V allows series connection of multiple LEDs; tight h_FE binning improves current matching across channels.

Relay Driver Circuit

DC Motor Speed Control

Use Scenario: Driving 12 V/24 V electromagnetic relays in PLC I/O modules and industrial control panels.

IC Role / Device Role / Timing Role: PNP switch controlling relay coil current path; base driven by microcontroller GPIO through current-limiting resistor.

Use Value: V_CEO = −80 V provides 3× safety margin over 24 V rail; I_C = −1 A accommodates typical relay coils (≤700 mA); low V_CE(sat) limits self-heating during continuous hold.

Use Scenario: Controlling brushed DC motor direction and speed in battery-powered tools and HVAC actuators.

IC Role / Device Role / Timing Role: High-side switch in H-bridge half-bridge stage or single-direction PWM driver.

Use Value: TO-92 package allows compact layout; h_FE consistency across I_C enables predictable base drive scaling; f_T > 10 MHz supports PWM frequencies up to 20 kHz without gain roll-off.

Audio Preamp Stage

LED Constant-Current Dimmer

Use Scenario: Low-noise, low-distortion voltage amplifier in microphone preamplifiers and sensor signal conditioning circuits.

IC Role / Device Role / Timing Role: Common-emitter linear amplifier with emitter degeneration resistor for stability and gain control.

Use Value: f_T = 100 MHz ensures flat response to 20 kHz; low I_CBO (≤ −0.1 μA) minimizes input offset drift; V_BE(on) = −1 V enables precise bias point setting.

Use Scenario: Regulating current through high-brightness LEDs in signage and automotive interior lighting.

IC Role / Device Role / Timing Role: Adjustable constant-current sink using emitter-follower configuration with sense resistor feedback.

Use Value: P_C = 1 W supports ≥500 mA LED strings at 2 V drop; V_CEO = −80 V allows series connection of multiple LEDs; tight h_FE binning improves current matching across channels.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC640TA	Same die, identical electrical specs; differs only in tape-and-reel packaging (TO-92, 2000 pcs/reel vs. BC640TF's 1000 pcs/reel).	No functional difference; suited for automated SMT assembly where reel format required.	Select BC640TA when high-volume pick-and-place integration is needed; BC640TF preferred for manual prototyping or low-volume production.
MPSA92	Higher V_CEO (−300 V), lower I_C (−500 mA), smaller h_FE range (25–100); TO-92 compatible but not pin-identical (E-C-B vs. E-B-C pinout).	Better for high-voltage flyback snubbers or CRT deflection circuits; unsuitable for direct BC640TF replacement without board revision.	Choose MPSA92 only when >100 V blocking is mandatory; avoid as drop-in substitute due to pinout mismatch and reduced current capability.

Compared with BC640TA and MPSA92, BC640TF offers optimal balance of current handling, gain linearity, and TO-92 mechanical fit for general-purpose medium-power PNP switching - making it preferable for relay, motor, and LED control where −1 A/−80 V ratings and E-C-B pinout are essential.

Availability

BC640TF is available at Aetrix Electronics and suitable for relay drivers, DC motor controllers, and LED dimmers requiring stable component supply, long-term manufacturability, and consistent parametric performance across production lots.

Supply support for BC640TF 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 (acquired Fairchild Semiconductor in 2016) is a global leader in energy-efficient semiconductor solutions for automotive, industrial, cloud computing, and IoT applications.

The BC640TF belongs to Fairchild's legacy general-purpose bipolar transistor family, engineered for reliability and ease of use in cost-sensitive, medium-power analog and switching circuits across industrial and consumer electronics.

FAQ

What is the pinout configuration of BC640TF?

The BC640TF uses a standard TO-92 package with Emitter–Collector–Base (ECB) pinout: when viewing the flat side with leads pointing downward, the leftmost pin is Emitter (1), center is Collector (2), and rightmost is Base (3). This ECB arrangement matches the original Fairchild BC640 series and differs from EBC layouts used in some other PNP transistors like MPSA92.

Is BC640TF RoHS compliant and lead-free?

Yes, BC640TF is RoHS compliant and lead-free per ON Semiconductor's product change notification PCN-1507-01. The device meets EU Directive 2011/65/EU and contains no intentionally added lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), or polybrominated diphenyl ethers (PBDE).

What is the maximum junction temperature for BC640TF?

The BC640TF has a maximum junction temperature (T_J) of +150°C, as specified in the Absolute Maximum Ratings table. This allows reliable operation in ambient temperatures up to +100°C when derated per the thermal resistance curve and mounted on PCBs with adequate copper area for heat spreading.

How does BC640TF compare to BC639 in circuit design?

BC640TF is the designated PNP complement to the NPN BC639, sharing identical package (TO-92), pinout (ECB), and matched electrical parameters including V_CEO/V_CEO, I_C, h_FE ranges, and f_T. This pairing enables symmetrical push-pull outputs, differential amplifiers, and complementary Darlington configurations without redesigning bias networks or layout.

Can BC640TF be used in linear amplifier applications?

Yes, BC640TF is qualified for linear amplifier use, with verified h_FE stability across I_C = −5 mA to −500 mA and f_T = 100 MHz. Its low V_CE(sat) and controlled V_BE(on) support Class-A and Class-AB biasing; however, thermal management is critical above 400 mW to maintain gain linearity and prevent thermal runaway.

BC640TF Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 1 A

Voltage - Collector Emitter Breakdown (Max):: 80 V

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

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 150mA, 2V

Power - Max:: 1 W

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC640TF FAQ

1.How can I place an order for BC640TF through Aetrix?

Please submit a Request for Quotation (RFQ) for BC640TF 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 BC640TF reliable?

The price and inventory of BC640TF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC640TF is usually 5 days.

3.What payment methods are accepted for BC640TF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC640TF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC640TF?

BC640TF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC640TF 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 BC640TF?

For technical support, including BC640TF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC640TF requirements.

6.How does Aetrix verify that BC640TF is sourced from the original manufacturer or authorized distributors?

All BC640TF 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 BC640TF meets industry standards.

7.What is the process for return or replacement of BC640TF?

All BC640TF units undergo pre-shipment inspection (PSI). If there is an issue with BC640TF, 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 BC640TF part is unused and in its original packaging.

Return procedure for BC640TF:

1.Submit a request within 90 days.

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

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