MPSA29 Darlington Transistor Pinout, Equivalent, Features, Applications and More

MPSA29 is an NPN Darlington BJT (bipolar junction transistor) available in a TO-92 package. The transistor is designed to provide very high DC current gain with 500mA or 0.5A collector current. As mentioned above, it is a Darlington transistor, which means it contains 2 NPN transistors inside in a special way which makes it capable of controlling higher current with minimum base current compared to a normal BJT. Moreover, the transistor also has a collector-emitter voltage of upto 100V, making it useful for high voltage applications. These and other features and capabilities of this transistor make it ideal for use in a variety of applications. In this article we will understand the MPSA29 Darlington Transistor Pinout, Equivalent, Features, Applications and other details.

MPSA29 Pin Configuration:

Pin1 is the Emitter pin: In an NPN transistor the emitter pin is connected to the ground, the current exits through the pin to the ground.

Pin2 is the Base pin: The base pin controls the flow of current from the collector to the emitter.

Pin3 is the Collector pin: The Collector pin is the output pin of the transistor. The current first enters from the positive rail of the circuit to the positive wire or pin of the load, then passes through the load and reaches the negative wire or pin of the load that is connected to the collector pin of the transistor. From there, the current goes through the transistor and reaches to its emitter pin and exits through the emitter pin to the ground or the negative rail of the circuit, making the circuit complete.

 

Key Specifications of 2N5771 Transistor:

• Package Type: TO-92
• Transistor Type: NPN Darlington
• Max Collector Current(I_C): 500mA
• Max Collector-Emitter Voltage (V_CEO): 100V
• Max Collector-Base Voltage (V_CBO): 100V
• Max Emitter-Base Voltage (VEBO): 12V
• Max Power Dissipation (PD): 625mW
• Collector to Emitter Saturation Voltage is: 2V to 1.5V
• DC Current Gain (h_FE): 10,000
• Transition Frequency (f_T): 125MHz
• Max Storage & Operating Temperature: -55 to +150 Centigrade

 

Replacement & Equivalent:

MPSA29G

 

MPSA29 Short Description:

MPSA29 is an NPN Darlington high voltage transistor designed for applications where very high current gain is required. The DC current gain of MPSA29 is up to 10,000 which makes it ideal for applications where you have a very small signal current at the base and want to drive a high current load, in these situations a normal NPN BJT transistor will not work because it has a current gain of only a few hundreds. Therefore, to overcome this problem, a Darlington transistor is used, for example, with a weak signal from a microcontroller, a logic IC or a sensor.

Inside the transistor there are 2 NPN transistors connected in a special way called a Darlington pair, which increases the gain to a great extent. The first transistor amplifies the base current to some extent and that amplified current goes to the second transistor which amplifies it more which results in an overall high current gain, due to which the transistor can drive a load with a very small amount of base current.

The collector-emitter voltage of the transistor is 100V which is another good advantage to use it in medium voltage applications, but it can also be used in low voltage circuits. Moreover the collector current of up to 500mA makes it capable to drive LEDs, lamps, relays, DC motors and other loads under 500mA.

Since it is a Darlington transistor, it contains two transistors inside so its base-emitter voltage is almost double that of a normal BJT transistor. For example, a normal BJT transistor requires 0.7V to turn ON, whereas the MPSA29 requires 1.2V to 2V. Additionally, its collector-emitter saturation voltage is also higher than that of a normal BJT transistor. So, it is important to keep these points in mind when you are using it in low voltage circuits.

Additionally the transistor features a good transition frequency of up to 125MHz, low leakage current and many other features which make it ideal for use in applications such as automation, industrial control, switching, amplification and wide variety of other general purpose applications.

 

Key Features:

High Collector Emitter Voltage of Up to 100V

Collector Current of Up to 500mA

DC Current Gain of Up to 10,000

Low Base Current Requirement

Low Leakage Current

Small TO-92 Package

Good Transition Frequency (125MHz)

Ideal for Sensor Applications

Ideal for Microcontroller Output Driving

High Reliability

Good Switching Performance

 

MPSA29 Applications:

Switching Circuits

Sensor Applications

Relay Drivers

Microcontroller Output Circuits

Alarm Circuits

Arduino Projects

Low Current DC Motor Driver Circuits

Raspberry Pi Projects

Signal Amplification

High Gain Amplification Circuits

Battery Operated Applications

Instrumentation Applications

And Wide Variety of Other General Purpose Applications

 

Safe Operating Guidelines:

Here are some important guidelines to safely operate the transistor.

• Do not operate the transistor at its absolute maximum ratings and always stay at least 20% below the maximum ratings.
• Always check the pin configuration of the transistor before using it in a circuit.
• Do not drive a load of more than 400mA, the maximum collector current is 500mA so by subtracting 20%, it will be 400mA.
• Do not drive a load of more than 80V. The same formula of 20% applies here.
• Always use a flyback diode when using motors, relays, solenoids or any other inductive loads.
• Operate the transistor within the given temperature range of -55°C to +150°C.

 

Datasheet:

To download the datasheet just copy and paste the below link in your browser.

https://www.alldatasheet.com/datasheet-pdf/view/157171/ONSEMI/MPSA29.html