TIP121 NPN Transistor: Darlington NPN, TIP121 Datasheet, Pinout
Trans Darlington NPN 80V 5A 3-Pin(3 Tab) TO-220 Tube
TIP121 is a transistor with an NPN Darlington pair. It is housed in a TO220 enclosure and is designed for standard amplification and low speed switching submissions. This post will unlock its pinout, datasheet, equivalent, circuit and more detailed information about TIP121.

Transistors TIP120 121 122 125 126 127
- TIP121 Pinout
- TIP121 CAD Model
- What is TIP121?
- What Feature does TIP121 have?
- What Application does TIP121 have?
- What can Replace TIP121?
- How does TIP121 Perform in a Circuit?
- Where & How to Use TIP121?
- What Package is TIP121 Available in?
- TIP121 Manufacturer
- Specifications
- Parts with Similar Specs
- Datasheet PDF
TIP121 Pinout

TIP121 Pinout
Pin# | Type | Parameters |
Pin#1 | Emitter | It is usually linked with the ground terminal. |
Pin#2 | Base | It used to turn on or off the transistor. We can say it works like a switch. |
Pin#3 | Collector | This terminal of the transistor is connected with the load. |
TIP121 CAD Model
Symbol

TIP121 Symbol
Footprint

TIP121 Footprint
3D Model

TIP121 3D Model
What is TIP121?
TIP121 is a transistor with an NPN Darlington pair. It is housed in a TO220 package and is designed for standard amplification and low speed switching submissions.
This transistor is ideal for simple switching circuits and can be used for loads that require moderate power.
It is the transistor category that is easily accessible in markets and has a lower price.
It provides many applications in electrical circuitries that way it is also famous in electrical industries. Because of these capabilities, it is the finest gadget to use when selecting an arbitrary swapping expedient.
What Feature does TIP121 have?
It is a transistor with medium power consumption.
Its attainable gain is fifty per cent (50).
The maximum voltage it can withstand around its collector and emitter terminals is one hundred volts (100).
The maximum current that may pass through the thrush's collector is three (3) amperes of direct current (DC).
The maximum voltage it can withstand around its base and emitter is five volts.
The maximum current that can pass through its base is one (1) ampere direct current (DC).
The maximum voltage that can be applied between the collector and the base is one hundred (100) volts.
Its maximum working temperature is 150 degrees Celsius.
It has a power dissipation of -65 watts.
What Application does TIP121 have?
Motor Drivers
Battery Chargers
Audio Amplifier Stages
Audio Power Amplifier Circuits
Audio Preamplifiers and Its Stages
Driving or Switching Loads under 5A
Output of Microcontrollers
What can Replace TIP121?
You can replace the TIP121 transistor with TIP100, TIP101, TIP102, TIP105, TIP106, TIP107, TIP110 or TIP126.
How does TIP121 Perform in a Circuit?
We're using a direct current motor as a load in this circuit. We use a controller component, which is mentioned in this circuit, to turn on or off. This control device sends a five-volt pulse to the transistor's base terminal. The mechanism to remember is that the controller circuit's ground must be linked with the transistor's emitter terminal. To limit the current, a ten-ohm resistance is linked with the base. Normally, the transistor will be turned off and there will be no base current.
Normally, the transistor will be turned off and there will be no base current. When the control unit sends a pulse to the base, electricity begins to flow and the transistor turns on. After this collector current is produced and the motor is started, the motor will continue to run until the base current is supplied. When the output of the control unit is reduced, the base current begins to fall, and the transistor ceases to function. The transistor then stops working, causing the collector current to drop to zero and the motor to shut down, as it was operating on collector current. We can see the circuit given below.

TIP121 Performance Circuit
Where & How to Use TIP121?
TIP121 can be utilized for switching as well as amplification. As a switch, it can drive a load of 5A, which is a strong collector current for driving a multitude of loads at once in electronic circuits such as motors, relays, parts of a circuit, high power LEDs, and so on. It can also be used to drive many loads from the output of an Arduino, Raspberry Pi, or another platform. It can also be utilized at the output of practically any microcontroller. With its high gain capabilities, it may also be used as an amplifier to amplify low level or low gain audio signals and other forms of low level or low gain signals to extremely high level or high gain.
What Package is TIP121 Available in?

TIP121 Package
TIP121 Manufacturer
STMicroelectronics is a global independent semiconductor company and is a leader in developing and delivering semiconductor solutions across the spectrum of microelectronics applications. An unrivalled combination of silicon and system expertise, manufacturing strength, Intellectual Property (IP) portfolio and strategic partners positions the Company at the forefront of System-on-Chip (SoC) technology and its products play a crucial role in enabling today's convergence trends.
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TIP102 NPN Transistor: Datasheet, Pinout, and Application
Specifications
- TypeParameter
- Factory Lead Time8 Weeks
- Mount
In electronic components, the term "Mount" typically refers to the method or process of physically attaching or fixing a component onto a circuit board or other electronic device. This can involve soldering, adhesive bonding, or other techniques to secure the component in place. The mounting process is crucial for ensuring proper electrical connections and mechanical stability within the electronic system. Different components may have specific mounting requirements based on their size, shape, and function, and manufacturers provide guidelines for proper mounting procedures to ensure optimal performance and reliability of the electronic device.
Through Hole - Mounting Type
The "Mounting Type" in electronic components refers to the method used to attach or connect a component to a circuit board or other substrate, such as through-hole, surface-mount, or panel mount.
Through Hole - Package / Case
refers to the protective housing that encases an electronic component, providing mechanical support, electrical connections, and thermal management.
TO-220-3 - Number of Pins3
- Transistor Element Material
The "Transistor Element Material" parameter in electronic components refers to the material used to construct the transistor within the component. Transistors are semiconductor devices that amplify or switch electronic signals and are a fundamental building block in electronic circuits. The material used for the transistor element can significantly impact the performance and characteristics of the component. Common materials used for transistor elements include silicon, germanium, and gallium arsenide, each with its own unique properties and suitability for different applications. The choice of transistor element material is crucial in designing electronic components to meet specific performance requirements such as speed, power efficiency, and temperature tolerance.
SILICON - Collector-Emitter Breakdown Voltage80V
- Collector-Emitter Saturation Voltage4V
- Number of Elements1
- hFEMin1000
- Operating Temperature
The operating temperature is the range of ambient temperature within which a power supply, or any other electrical equipment, operate in. This ranges from a minimum operating temperature, to a peak or maximum operating temperature, outside which, the power supply may fail.
150°C TJ - Packaging
Semiconductor package is a carrier / shell used to contain and cover one or more semiconductor components or integrated circuits. The material of the shell can be metal, plastic, glass or ceramic.
Tube - JESD-609 Code
The "JESD-609 Code" in electronic components refers to a standardized marking code that indicates the lead-free solder composition and finish of electronic components for compliance with environmental regulations.
e3 - Part Status
Parts can have many statuses as they progress through the configuration, analysis, review, and approval stages.
Active - Moisture Sensitivity Level (MSL)
Moisture Sensitivity Level (MSL) is a standardized rating that indicates the susceptibility of electronic components, particularly semiconductors, to moisture-induced damage during storage and the soldering process, defining the allowable exposure time to ambient conditions before they require special handling or baking to prevent failures
1 (Unlimited) - Number of Terminations3
- ECCN Code
An ECCN (Export Control Classification Number) is an alphanumeric code used by the U.S. Bureau of Industry and Security to identify and categorize electronic components and other dual-use items that may require an export license based on their technical characteristics and potential for military use.
EAR99 - Terminal Finish
Terminal Finish refers to the surface treatment applied to the terminals or leads of electronic components to enhance their performance and longevity. It can improve solderability, corrosion resistance, and overall reliability of the connection in electronic assemblies. Common finishes include nickel, gold, and tin, each possessing distinct properties suitable for various applications. The choice of terminal finish can significantly impact the durability and effectiveness of electronic devices.
Matte Tin (Sn) - Voltage - Rated DC
Voltage - Rated DC is a parameter that specifies the maximum direct current (DC) voltage that an electronic component can safely handle without being damaged. This rating is crucial for ensuring the proper functioning and longevity of the component in a circuit. Exceeding the rated DC voltage can lead to overheating, breakdown, or even permanent damage to the component. It is important to carefully consider this parameter when designing or selecting components for a circuit to prevent any potential issues related to voltage overload.
80V - Max Power Dissipation
The maximum power that the MOSFET can dissipate continuously under the specified thermal conditions.
65W - Current Rating
Current rating is the maximum current that a fuse will carry for an indefinite period without too much deterioration of the fuse element.
5A - Base Part Number
The "Base Part Number" (BPN) in electronic components serves a similar purpose to the "Base Product Number." It refers to the primary identifier for a component that captures the essential characteristics shared by a group of similar components. The BPN provides a fundamental way to reference a family or series of components without specifying all the variations and specific details.
TIP121 - Pin Count
a count of all of the component leads (or pins)
3 - Polarity
In electronic components, polarity refers to the orientation or direction in which the component must be connected in a circuit to function properly. Components such as diodes, capacitors, and LEDs have polarity markings to indicate which terminal should be connected to the positive or negative side of the circuit. Connecting a component with incorrect polarity can lead to malfunction or damage. It is important to pay attention to polarity markings and follow the manufacturer's instructions to ensure proper operation of electronic components.
NPN - Number of Channels1
- Element Configuration
The distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals.
Single - Power Dissipation
the process by which an electronic or electrical device produces heat (energy loss or waste) as an undesirable derivative of its primary action.
2W - Transistor Application
In the context of electronic components, the parameter "Transistor Application" refers to the specific purpose or function for which a transistor is designed and used. Transistors are semiconductor devices that can amplify or switch electronic signals and are commonly used in various electronic circuits. The application of a transistor can vary widely depending on its design and characteristics, such as whether it is intended for audio amplification, digital logic, power control, or radio frequency applications. Understanding the transistor application is important for selecting the right type of transistor for a particular circuit or system to ensure optimal performance and functionality.
SWITCHING - Transistor Type
Transistor type refers to the classification of transistors based on their operation and construction. The two primary types are bipolar junction transistors (BJTs) and field-effect transistors (FETs). BJTs use current to control the flow of current, while FETs utilize voltage to control current flow. Each type has its own subtypes, such as NPN and PNP for BJTs, and MOSFETs and JFETs for FETs, impacting their applications and characteristics in electronic circuits.
NPN - Darlington - Collector Emitter Voltage (VCEO)
Collector-Emitter Voltage (VCEO) is a key parameter in electronic components, particularly in transistors. It refers to the maximum voltage that can be applied between the collector and emitter terminals of a transistor while the base terminal is open or not conducting. Exceeding this voltage limit can lead to breakdown and potential damage to the transistor. VCEO is crucial for ensuring the safe and reliable operation of the transistor within its specified limits. Designers must carefully consider VCEO when selecting transistors for a circuit to prevent overvoltage conditions that could compromise the performance and longevity of the component.
80V - Max Collector Current
Max Collector Current is a parameter used to specify the maximum amount of current that can safely flow through the collector terminal of a transistor or other electronic component without causing damage. It is typically expressed in units of amperes (A) and is an important consideration when designing circuits to ensure that the component operates within its safe operating limits. Exceeding the specified max collector current can lead to overheating, degradation of performance, or even permanent damage to the component. Designers must carefully consider this parameter when selecting components and designing circuits to ensure reliable and safe operation.
5A - DC Current Gain (hFE) (Min) @ Ic, Vce
The parameter "DC Current Gain (hFE) (Min) @ Ic, Vce" in electronic components refers to the minimum value of the DC current gain, denoted as hFE, under specific operating conditions of collector current (Ic) and collector-emitter voltage (Vce). The DC current gain hFE represents the ratio of the collector current to the base current in a bipolar junction transistor (BJT), indicating the amplification capability of the transistor. The minimum hFE value at a given Ic and Vce helps determine the transistor's performance and efficiency in amplifying signals within a circuit. Designers use this parameter to ensure proper transistor selection and performance in various electronic applications.
1000 @ 3A 3V - Current - Collector Cutoff (Max)
The parameter "Current - Collector Cutoff (Max)" refers to the maximum current at which a transistor or other electronic component will cease to conduct current between the collector and emitter terminals. This parameter is important in determining the maximum current that can flow through the component when it is in the cutoff state. Exceeding this maximum cutoff current can lead to malfunction or damage of the component. It is typically specified in the component's datasheet and is crucial for proper circuit design and operation.
500μA - JEDEC-95 Code
JEDEC-95 Code is a standardized identification system used by the Joint Electron Device Engineering Council to categorize and describe semiconductor devices. This code provides a unique alphanumeric identifier for various memory components, ensuring consistency in documentation and communication across the electronics industry. The format includes information about the type, capacity, and technology of the device, facilitating easier specification and understanding for manufacturers and engineers.
TO-220AB - Vce Saturation (Max) @ Ib, Ic
The parameter "Vce Saturation (Max) @ Ib, Ic" in electronic components refers to the maximum voltage drop across the collector-emitter junction when the transistor is in saturation mode. This parameter is specified at a certain base current (Ib) and collector current (Ic) levels. It indicates the minimum voltage required to keep the transistor fully conducting in saturation mode, ensuring that the transistor operates efficiently and does not enter the cutoff region. Designers use this parameter to ensure proper transistor operation and to prevent overheating or damage to the component.
4V @ 20mA, 5A - Collector Base Voltage (VCBO)
Collector Base Voltage (VCBO) is the maximum allowable voltage that can be applied between the collector and base terminals of a bipolar junction transistor when the emitter is open. It is a critical parameter that determines the voltage rating of the transistor and helps prevent breakdown in the collector-base junction. Exceeding this voltage can lead to permanent damage or failure of the component.
80V - Emitter Base Voltage (VEBO)
Emitter Base Voltage (VEBO) is a parameter used in electronic components, particularly in transistors. It refers to the maximum voltage that can be applied between the emitter and base terminals of a transistor without causing damage to the device. Exceeding this voltage limit can lead to breakdown of the transistor and potential failure. VEBO is an important specification to consider when designing circuits to ensure the proper operation and reliability of the components. It is typically provided in the datasheet of the transistor and should be carefully observed to prevent any potential damage during operation.
5V - VCEsat-Max
VCEsat-Max refers to the maximum collector-emitter saturation voltage of a bipolar junction transistor (BJT) or an insulated gate bipolar transistor (IGBT). It is a crucial parameter that indicates the minimum voltage drop across the collector-emitter junction when the transistor is in saturation mode. This parameter is important for determining the efficiency and performance of the transistor in switching applications. A lower VCEsat-Max value indicates better performance and reduced power losses in the transistor during operation. Designers often consider this parameter when selecting transistors for applications where minimizing power dissipation is critical.
4 V - Height15.75mm
- Length10.4mm
- Width4.6mm
- REACH SVHC
The parameter "REACH SVHC" in electronic components refers to the compliance with the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) regulation regarding Substances of Very High Concern (SVHC). SVHCs are substances that may have serious effects on human health or the environment, and their use is regulated under REACH to ensure their safe handling and minimize their impact.Manufacturers of electronic components need to declare if their products contain any SVHCs above a certain threshold concentration and provide information on the safe use of these substances. This information allows customers to make informed decisions about the potential risks associated with using the components and take appropriate measures to mitigate any hazards.Ensuring compliance with REACH SVHC requirements is essential for electronics manufacturers to meet regulatory standards, protect human health and the environment, and maintain transparency in their supply chain. It also demonstrates a commitment to sustainability and responsible manufacturing practices in the electronics industry.
No SVHC - Radiation Hardening
Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation, especially for environments in outer space (especially beyond the low Earth orbit), around nuclear reactors and particle accelerators, or during nuclear accidents or nuclear warfare.
No - RoHS Status
RoHS means “Restriction of Certain Hazardous Substances” in the “Hazardous Substances Directive” in electrical and electronic equipment.
ROHS3 Compliant - Lead Free
Lead Free is a term used to describe electronic components that do not contain lead as part of their composition. Lead is a toxic material that can have harmful effects on human health and the environment, so the electronics industry has been moving towards lead-free components to reduce these risks. Lead-free components are typically made using alternative materials such as silver, copper, and tin. Manufacturers must comply with regulations such as the Restriction of Hazardous Substances (RoHS) directive to ensure that their products are lead-free and environmentally friendly.
Lead Free
Parts with Similar Specs
- ImagePart NumberManufacturerMountPackage / CasePolarityCollector Emitter Breakdown VoltageMax Collector CurrentCollector Emitter Saturation VoltagehFE MinMax Power DissipationView Compare
TIP121
Through Hole
TO-220-3
NPN
80 V
5 A
4 V
1000
65 W
Through Hole
TO-220-3
-
100 V
6 A
1.5 V
15
2 W
Through Hole
TO-220-3
NPN
100 V
8 A
2 V
1000
80 W
Through Hole
TO-220-3
NPN
100 V
2 A
2.5 V
500
50 W
Datasheet PDF
- Datasheets :
What type of power does TIP121 need?
Moderate power.
In what industries is TIP121 famous?
Electrical industries.
What is TIP121's load?
5A.
What is TIP121s ability to be used as an amplifier to amplify low level or low gain audio signals?
High gain capabilities.
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