It is good to use an N MOSFET when you need a device that has lower on-resistance and higher electron mobility, which makes it more efficient for high-speed switching applications. N MOSFETs are typically used when you need to switch the low side of the load (connecting the load to ground) because they require a positive voltage relative to the source to turn on.
They are ideal for applications such as power management, DC-DC converters, and motor control, where efficient switching is critical.
You should use an n-channel MOSFET or a p-channel MOSFET depending on the polarity of the voltage you need to control and the position of the load in your circuit. N-channel MOSFETs are generally used for low-side switching, where the source is connected to ground, and the load is connected between the drain and the positive supply.
P-channel MOSFETs are used for high-side switching, where the source is connected to the positive supply, and the load is connected between the drain and ground.
P-channel MOSFETs require a negative voltage relative to the source to turn on, making them suitable for applications where the control signal needs to be referenced to ground.
N-MOSFETs are preferred over P-MOSFETs in many applications due to their superior electrical characteristics.
N-MOSFETs have higher electron mobility compared to hole mobility in P-MOSFETs, which translates to lower on-resistance and faster switching times. This makes N-MOSFETs more efficient and better suited for high-speed and high-efficiency applications.
Additionally, N-MOSFETs tend to be cheaper to manufacture because the process for creating n-type channels is simpler and more cost-effective than that for p-type channels.
The difference between P and N type MOSFETs lies in the type of charge carriers that flow through their channels and their corresponding electrical characteristics.
In N type MOSFETs, the primary charge carriers are electrons, which have higher mobility, resulting in lower on-resistance and faster switching. In P type MOSFETs, the primary charge carriers are holes, which have lower mobility, leading to higher on-resistance and slower switching compared to N type MOSFETs. N type MOSFETs are turned on by applying a positive voltage to the gate relative to the source, while P type MOSFETs are turned on by applying a negative voltage to the gate relative to the source.
To know which MOSFET to use, consider the requirements of your specific application.
If you need lower on-resistance, faster switching, and are working with low-side switching, an N-channel MOSFET is likely the better choice. If your application requires high-side switching and you need the control signal to be referenced to ground, a P-channel MOSFET might be more suitable. Additionally, evaluate the voltage and current ratings, switching speed, thermal performance, and cost of the MOSFET to ensure it meets the needs of your circuit.
Examining the datasheets of potential MOSFETs can help you make an informed decision based on these parameters.