onsemi SPZT2907AT1G PNP Bipolar Junction Transistor: Datasheet, Pinout, and Application Circuit Guide

The SPZT2907AT1G from onsemi is a popular PNP Bipolar Junction Transistor (BJT) housed in a compact SOT-223 package, designed for a variety of switching and amplification purposes. This device is renowned for its high current handling capability and robust performance in consumer and industrial electronics. This guide provides a detailed overview of its datasheet specifications, pinout configuration, and a practical application circuit.

Datasheet Overview and Key Specifications

The SPZT2907AT1G is a general-purpose PNP transistor characterized by its ability to switch and amplify electronic signals. Its key electrical specifications make it suitable for a wide range of applications, from power management to signal inversion.

Polarity: PNP

Package: SOT-223

Collector-Base Voltage (VCBO): -60 V

Collector-Emitter Voltage (VCEO): -40 V

Emitter-Base Voltage (VEBO): -5.0 V

Continuous Collector Current (IC): -600 mA

Total Power Dissipation (Ptot): 1.5 W (at Ta = 25°C)

DC Current Gain (hFE): Typically 100 to 300 at IC = -10 mA, VCE = -1.0 V

Transition Frequency (fT): 200 MHz (typical)

These specifications highlight the transistor's high-voltage and high-current capabilities, making it an excellent choice for driving loads like relays, motors, and LEDs.

Pinout Configuration

Correctly identifying the pinout is crucial for proper circuit design and PCB layout. The SOT-223 package has four pins, but two are internally connected to the same terminal (typically the collector), providing a larger thermal pad for better heat dissipation.

The pinout for the SPZT2907AT1G is as follows:

Pin 1 (Base): The control input. A current applied to this pin (sunk from it for a PNP device) controls the flow of current between the emitter and collector.

Pin 2 (Collector): The output terminal. This pin is connected to the load.

Pins 3 & 4 (Emitter): These two pins are internally connected. They represent the common reference point and are typically connected to the positive supply rail (for a PNP in a switching role).

Application Circuit Guide: A Simple Switch

One of the most common uses for the SPZT2907AT1G is as a low-side switch. This circuit allows a small signal from a microcontroller (e.g., an Arduino) to control a much larger load, such as a motor or a string of high-power LEDs.

Components Required:

Microcontroller (MCU)

SPZT2907AT1G Transistor

Load (e.g., a 12V DC Motor)

Diode (1N4001 or similar Flyback Diode for inductive loads)

Base Resistor (1kΩ typical)

12V Power Supply

Circuit Operation:

1. The emitter is connected to the positive terminal of the 12V supply.

2. The load (motor) is connected between the collector and ground.

3. The flyback diode is placed in reverse bias across the motor (anode to collector, cathode to emitter) to protect the transistor from voltage spikes when the motor is turned off.

4. A current-limiting resistor (e.g., 1kΩ) is connected between the MCU's digital output pin and the base of the transistor.

5. When the MCU output is LOW (0V), a current flows out of the base, turning the PNP transistor ON. This allows current to flow from the emitter, through the transistor, to the collector, and through the motor to ground, activating it.

6. When the MCU output is HIGH (e.g., 5V), the voltage difference between the base and emitter is minimized, turning the transistor OFF and cutting power to the motor.

This circuit effectively uses the transistor as a solid-state switch, enabling a low-power MCU to safely control a high-power device.

ICGOOODFIND Summary

The onsemi SPZT2907AT1G is a versatile and robust PNP BJT ideal for a multitude of switching applications. Its SOT-223 package offers superior power dissipation, and its electrical characteristics provide a reliable solution for designers needing to interface control logic with higher-power loads. Understanding its pinout and basic switching circuit is fundamental for effective implementation in electronic designs.

Keywords: PNP Transistor, SOT-223, Switching Circuit, BJT, SPZT2907AT1G