2SA608NG-NPA-AT

2SA608NG-NPA-AT Application Field and Working Principle

The 2SA608NG-NPA-AT is a bipolar transistor, specifically a PNP type, with a low voltage, low power and a high current capability. This transistor is of the small signal variant and can be used in applications where the signals are not too intense such as small audio amplifiers, and low power switching circuits. It has a maximum voltage rating of 40V and can source up to 1A of current.

Application Fields

The 2SA608NG-NPA-AT is especially suited for many low power audio applications such as low power amplifiers and head-phones drivers. It is also used in the control of motors to provide assistance in re-circulating current and providing overload protection. Its high current capabilities make it suitable for applications in lights, relays, and other switching applications. The applications for this device are numerous and varied.

Working Principle

The 2SA608NG-NPA-AT is a PNP bipolar transistor, and as such is composed of three layers of semiconductor material, each layer having different dopant types and concentrations. The layers are called emitter, base, and collector. The emitter region is heavily doped with P type dopants to allow for positive charge carriers to enter and leave the emitter region. The base region is lightly doped with a combination of P and N type dopants. The P type dopants mostly are on the emitter side while the N type dopants are on the collector side. This configuration of N and P type dopants adds a double change effect on the electronic flow between the emitter and collector. The collector region is heavily doped with N type dopants to allow for more severe control of the flow of current within the device.

The operation of the 2SA608NG-NPA-AT is based primarily on the number of majority carriers in the two junctions, the emitter-base junction and the collector-base junction. The bipolar junction transistor operates because of the pulling effect called the ‘Early Effect’. The voltage between the base and emitter controls the current flow between the collector and emitter by altering the depletion zone in the base collector junction. As the depletion zone width decreases, the transistor’s current amplification factor (β) increases. When the base voltage increases, the magnitude of the emitter-base junction’s majority carriers (electrons or holes) increases and, therefore, the current flow increases. This phenomenon is called the ‘Forward Early Effect’.

When the emitter-base junction is reverse bias, the majority carriers in the emitter-base junction and collector-base junction start to deplete and the current flow begins to decrease. This phenomenon is referred to as the ‘Reverse Early Effect’. The current flow in the 2SA608NG-NPA-AT is largely determined by the reverse Early effect. The higher the current flow, the higher the voltage is needed to slow it down.

Conclusion

The 2SA608NG-NPA-AT is a low voltage and low power PNP bipolar transistor equipped with a high current capability. It is specifically suited for low power audio applications and small motor applications, as well as other light and relay switches. Its operation is based on the emitter-base junction and collector-base junction’s majority carriers, resulting in the Forward and Reverse Early Effect.