TIP125 Darlington PNP transistor 60V 5A

TIP125 – Darlington PNP Transistor

The TIP125 is a high-performance Darlington PNP transistor that is designed for use in a variety of applications requiring high current and voltage, such as motor control, switching, and amplifying signals.

Key Specifications

• Type: PNP Darlington Transistor
• Collector-Emitter Voltage (Vce): Up to 60 V
• Collector Current (Ic): Up to 5 A
• DC Current Gain (hFE): Typically 1000 to 3000 at low base currents
• Power Dissipation: 65 W (with proper heat sinking)
• Package Type: TO-220 for good heat dissipation characteristics
• Temperature Range: Operating up to 150°C (junction temperature)
• Rise and Fall Time: Generally suitable for low to moderate frequencies, with gain decreasing at higher frequencies.

Pin Configuration

The pin configuration for the TIP125 in a TO-220 package is as follows:

Copy      +-----+
      |     |
  1   |  C  | Collector
      |     |
  2   |  B  | Base
      |     |
  3   |  E  | Emitter
      +-----+

Where:

• C (Collector): Pin 1
• B (Base): Pin 2
• E (Emitter): Pin 3

Applications

The TIP125 can be used in various applications, including:

1. Motor Drivers: To control DC motors and stepper motors.
2. Relay Drivers: To switch relays on and off.
3. Transistor Amplifiers: For amplifying low-level signals in applications where high gain is required.
4. LED Drivers: For switching higher power LED arrays.
5. Load Switches: To turn on/off other electronic components in a circuit.

Basic Circuit Design

Here’s a simple example of how you might use the TIP125 in a motor control circuit:

Copy   Vcc (e.g., 12V)
     |
     |
   .-.
   | | Motor (load)
   '-'
     |
     +------+
     |      |
   TIP125   |     
     |      |
     |      |
    Emitter |
      |     |
      |     |
    Ground  |
      L     |
      __    | 
    |    |  |   
    | R  |  |   
    |____|  |  
              |
          Control Signal

• In this circuit:
  • Vcc is the power source.
  • The motor is connected between the collector of the TIP125 and Vcc.
  • The emitter of the TIP125 is connected to ground.
  • A control signal drives the base of the TIP125 to control the motor.

Important Notes

1. Base Resistor Calculation: To properly drive the TIP125, a base resistor (R) may be needed to limit the base current. Use the formula: [ R = \frac{(V_{control} – V_{be})}{I_b} ] where ( V_{control} ) is the voltage of the control signal, ( V_{be} ) is approximately 1.2V for Darlington transistors, and ( I_b ) can be calculated based on the required collector current divided by the gain (hFE).
2. Flyback Diode: If controlling inductive loads (like motors), ensure to place a flyback diode across the load to protect the transistor from back EMF.
3. Thermal Management: Ensure appropriate heat sinking if the transistor operates near its maximum ratings to avoid thermal runaway and damage.
4. Voltage and Current Limits: Always operate within the specified limits of the transistor to prevent damage and ensure reliable operation.