- BSS84 is P-Channel Enhancement Mode MOSFET (Metal Oxide Semiconductor Field Effect Transistor) and is used as a high-speed switching device in applications. The device is designed using ON Semiconductor’s proprietary, high cell density, DMOS technology.
Pin Configuration
BSS84 is a three-pin device as shown in the figure and the function of each of those pins is stated below.
| Pin | Name | Function |
|---|---|---|
| 1 | Drain | Current which comes into the device through the Source pin goes out through the Drain pin. |
| 2 | Gate | MOSFET gets turned ON and OFF depending on the voltage applied to gate. |
| 3 | Source | Current comes into the device from the Source pin. |
Working
- When the -5V gate signal is given through the microcontroller at a set time, then MOSFET will start performing.
- The current supplies throughout the transistor & this current flow can lead to a drop in voltage beyond load. This voltage drop will switch ON the load.
- The load used in the circuit is the motor which will rotate continuously until the microcontroller negative voltage is there & the direct voltage like ‘Vo’ will go to 0V to stop the motor from rotating.
- Thus, BSS84 is used as a switching device in the above application & in a similar method, we can utilize the transistor in other different circuits.
Applications of BSS84 MOSFET
- Functions of Power Management.
- Line Current Interrupter within Telephone Sets.
- Liner Transformer Drivers.
- Load Switching.
- Protection of Battery.
![](https://www.semiconductorforu.com/wp-content/uploads/2025/03/2020-Battery_KE1010R2-970x250-ROTATING-FINAL-V3.gif")
