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

onsemi BC635RL1

Name: BC635RL1
Brand: onsemi
SKU: BC635RL1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC635RL1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 Long Body, Formed Leads

Datasheet:: BC635RL1.pdf

Description:: TRANS NPN 45V 1A TO92

Quantity:: RFQ Add To RFQ list

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Inventory:6,770

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Product details

Overview

BC635RL1 from ON Semiconductor is an NPN silicon high-current transistor in TO-92 package, rated for V_CEO = 45 V, I_C = 1.0 A, P_D = 625 mW at T_A = 25°C, with h_FE = 25–250 (IC = 5 mA to 500 mA), used in general-purpose switching and linear amplification circuits.

For engineers reviewing the BC635RL1 datasheet, pinout, applications, or equivalent options, key selection considerations include its 45 V V_CEO, 1.0 A continuous collector current, TO-92 thermal resistance (R_JA = 200 °C/W), saturation voltage (V_CE(sat) ≤ 0.5 V at I_C = 500 mA/I_B = 50 mA), and f_T = 200 MHz bandwidth capability.

Technical Context

The BC635RL1 operates as a medium-power NPN bipolar junction transistor optimized for DC switching and analog amplification in industrial and consumer electronics. Its design supports stable gain across collector currents from 5 mA to 500 mA, with verified V_BE(on) ≤ 1.0 V and V_CE(sat) ≤ 0.5 V under specified drive conditions.

Thermal performance is defined by R_JA = 200 °C/W (ambient) and R_JC = 83.3 °C/W (case), enabling operation from −55°C to +150°C junction temperature. Input capacitance (C_ib = 50 pF) and output capacitance (C_ob = 7.0 pF) are characterized at 1 MHz, supporting moderate-frequency signal handling.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum safe collector-emitter voltage before breakdown under open-base condition.
I_C (continuous)	1.0 A - Continuous collector current rating at T_A = 25°C; derates linearly above ambient.
P_D @ T_A = 25°C	625 mW - Total power dissipation limit with free-air convection cooling.
h_FE	25–250 - DC current gain range across 5 mA to 500 mA collector current, enabling predictable biasing.
V_CE(sat)	≤ 0.5 V - Low saturation voltage ensures minimal power loss in switching applications.
f_T	200 MHz - Current-gain bandwidth product confirms suitability for RF preamp and fast-switching use.

Pinout & Package

BC635RL1 uses the TO-92 (Case 29, Style 14) plastic package with 3 leads, designed for through-hole mounting and manual or automated assembly. Thermal resistance is R_JA = 200 °C/W and R_JC = 83.3 °C/W.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current exit path; referenced for base drive and common-emitter configuration grounding.
2	Collector	Main current input terminal; connects to load or supply rail in switching topologies.
3	Base	Control electrode; requires ~50 mA drive for full saturation at 500 mA collector current.

Key Features

Feature	Design Value
High current capability	Rated for 1.0 A continuous collector current with validated SOA up to 1000 mA at low V_CE.
Low saturation voltage	V_CE(sat) ≤ 0.5 V ensures <0.25 W conduction loss at 500 mA, improving efficiency in switch-mode designs.
Wide h_FE range	25–250 enables robust biasing across production lots without individual trimming.
TO-92 Pb-free option	BC635RL1G variant available with RoHS-compliant lead finish and tape-and-reel packaging.

Applications

Power Supply Switching	Audio Pre-amplifier Stage
Use Scenario: Used as a series pass or switching element in discrete linear regulators and DC-DC converter auxiliary stages. IC Role / Device Role / Timing Role: NPN transistor operating in active or saturation region to control output voltage or enable/disable rails. Use Value: 45 V V_CEO and 1.0 A I_C support 24 V industrial supplies; low V_CE(sat) reduces dropout and heat generation.	Use Scenario: Amplifies low-level microphone or line-level signals in portable audio equipment. IC Role / Device Role / Timing Role: Discrete NPN configured in common-emitter topology for voltage gain with DC bias stability. Use Value: h_FE ≥ 25 at 5 mA ensures reliable small-signal amplification; f_T = 200 MHz preserves audio band fidelity.
Motor Driver Interface	Relay Driver Circuit
Use Scenario: Drives small DC motors (e.g., fans, actuators) in embedded control systems. IC Role / Device Role / Timing Role: Switching transistor interfacing microcontroller GPIO to inductive motor load. Use Value: 1.0 A rating handles peak stall currents; built-in V_CEO = 45 V withstands flyback transients with proper snubbing.	Use Scenario: Activates electromechanical relays in PLC I/O modules and appliance control boards. IC Role / Device Role / Timing Role: High-gain NPN switch translating logic-level signals into relay coil current. Use Value: h_FE ≥ 100 at 150 mA ensures full relay actuation with minimal MCU drive current; TO-92 footprint simplifies layout.

Power Supply Switching

Audio Pre-amplifier Stage

Use Scenario: Used as a series pass or switching element in discrete linear regulators and DC-DC converter auxiliary stages.

IC Role / Device Role / Timing Role: NPN transistor operating in active or saturation region to control output voltage or enable/disable rails.

Use Value: 45 V V_CEO and 1.0 A I_C support 24 V industrial supplies; low V_CE(sat) reduces dropout and heat generation.

Use Scenario: Amplifies low-level microphone or line-level signals in portable audio equipment.

IC Role / Device Role / Timing Role: Discrete NPN configured in common-emitter topology for voltage gain with DC bias stability.

Use Value: h_FE ≥ 25 at 5 mA ensures reliable small-signal amplification; f_T = 200 MHz preserves audio band fidelity.

Motor Driver Interface

Relay Driver Circuit

Use Scenario: Drives small DC motors (e.g., fans, actuators) in embedded control systems.

IC Role / Device Role / Timing Role: Switching transistor interfacing microcontroller GPIO to inductive motor load.

Use Value: 1.0 A rating handles peak stall currents; built-in V_CEO = 45 V withstands flyback transients with proper snubbing.

Use Scenario: Activates electromechanical relays in PLC I/O modules and appliance control boards.

IC Role / Device Role / Timing Role: High-gain NPN switch translating logic-level signals into relay coil current.

Use Value: h_FE ≥ 100 at 150 mA ensures full relay actuation with minimal MCU drive current; TO-92 footprint simplifies layout.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC637RL1	V_CEO = 60 V, V_CBO = 60 V - higher voltage rating; otherwise identical package, pinout, and gain profile.	Suitable where system transients exceed 45 V but ≤ 60 V; no change to PCB or drive circuitry required.	Select BC637RL1 when higher breakdown margin is needed without altering layout or bias network.
BC817-40,215	SOT-23 package, 500 mA I_C, h_FE = 250–630 - smaller footprint, lower current, higher gain, surface-mount only.	Used in space-constrained, high-density PCBs; not drop-in compatible due to package and thermal limits.	Choose BC817-40,215 for compact SMT designs requiring >250 h_FE, accepting reduced current and power handling.

Compared with BC635RL1, BC637RL1 offers higher voltage tolerance while maintaining identical form factor and drive requirements, whereas BC817-40,215 trades current capacity and thermal robustness for miniaturization and higher small-signal gain in SMT layouts.

Availability

BC635RL1 is available at Aetrix Electronics and suitable for power supply switching, audio pre-amplification, motor interface, and relay driver applications requiring stable component supply, long-term manufacturability, and RoHS-compliant sourcing.

Supply support for BC635RL1 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 (now onsemi) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BC635RL1 belongs to the BC63x family of high-current NPN transistors designed for cost-sensitive, medium-power linear and switching applications where reliability, consistent gain, and proven TO-92 thermal performance are critical.

FAQ

What is the maximum collector-emitter voltage rating for BC635RL1?

The BC635RL1 has a maximum collector-emitter voltage (V_CEO) rating of 45 Vdc under open-base conditions. This value is confirmed in the Absolute Maximum Ratings table and applies at T_A = 25°C. Exceeding this voltage risks avalanche breakdown and permanent device damage, so design margins should maintain operation below 40 V in typical applications using BC635RL1.

Does BC635RL1 support Pb-free soldering processes?

Yes, BC635RL1 is available in a standard leaded version, and its Pb-free counterpart is designated BC635RL1G. Both share identical electrical specifications and TO-92 packaging, with BC635RL1G complying with RoHS Directive 2011/65/EU and qualified for reflow soldering per J-STD-020. The BC635RL1G variant is explicitly listed in the Ordering Information section of the official datasheet.

What is the DC current gain (h_FE) range for BC635RL1 at 500 mA collector current?

At I_C = 500 mA, V_CE = 2.0 V, and T_A = 25°C, the BC635RL1 exhibits h_FE = 40–160 (min–max), as specified in the Electrical Characteristics table. This range reflects production lot variation and ensures predictable biasing across units without requiring individual calibration when using BC635RL1 in linear amplifier or saturated switch designs.

Can BC635RL1 be used in RF applications?

The BC635RL1 has a current-gain bandwidth product (f_T) of 200 MHz, measured at I_C = 50 mA, V_CE = 2.0 V, and f = 100 MHz. While not optimized for high-frequency RF power amplification, BC635RL1 supports low-power RF pre-amplifier and oscillator buffer stages up to ~50 MHz, provided layout minimizes parasitic inductance and capacitance. Its C_ob = 7.0 pF and C_ib = 50 pF further define usable frequency limits in practical BC635RL1 implementations.

What is the thermal resistance from junction to ambient (R_JA) for BC635RL1?

The BC635RL1 has a thermal resistance from junction to ambient (R_JA) of 200 °C/W under standard free-air conditions, as published in the Thermal Characteristics table. This value assumes no heatsink and natural convection; actual board-level R_JA may improve with copper pour or airflow. For sustained 1.0 A operation, junction temperature must remain ≤150°C, requiring careful thermal design when using BC635RL1 in enclosed or high-ambient environments.

BC635RL1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 Long Body, Formed Leads

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 45 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:: 625 mW

Frequency - Transition:: 200MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92 (TO-226)

BC635RL1 FAQ

1.How can I place an order for BC635RL1 through Aetrix?

Please submit a Request for Quotation (RFQ) for BC635RL1 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 BC635RL1 reliable?

The price and inventory of BC635RL1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC635RL1 is usually 5 days.

3.What payment methods are accepted for BC635RL1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC635RL1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC635RL1?

BC635RL1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC635RL1 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 BC635RL1?

For technical support, including BC635RL1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC635RL1 requirements.

6.How does Aetrix verify that BC635RL1 is sourced from the original manufacturer or authorized distributors?

All BC635RL1 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 BC635RL1 meets industry standards.

7.What is the process for return or replacement of BC635RL1?

All BC635RL1 units undergo pre-shipment inspection (PSI). If there is an issue with BC635RL1, 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 BC635RL1 part is unused and in its original packaging.

Return procedure for BC635RL1:

1.Submit a request within 90 days.

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

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