The 2N7002LT1G from onsemi is an N-Channel MOSFET designed for small signal switching applications. Housed in a compact SOT-23 package, this MOSFET supports a drain-source voltage (VDSS) of up to 60V and a continuous drain current (ID) of 115mA at 25°C. It features a low on-state resistance (RDS(on)) of 7.5 Ohms at VGS = 10V, enhancing its efficiency in circuit operation.
The device also offers robust thermal performance with a maximum junction-to-ambient thermal resistance (RθJA) of 556 °C/W on an FR-5 board. For applications requiring higher thermal efficiency, the device's performance on an alumina substrate shows an improved RθJA of 417 °C/W. The 2N7002LT1G is designed to handle pulsed drain currents (IDM) up to 800mA, providing flexibility for a range of design requirements. Its dynamic characteristics include input, output, and reverse transfer capacitances, facilitating accurate modeling in switching applications.
MOSFET
MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) are a type of transistor used for amplifying or switching electronic signals. They are widely used in electronic devices due to their high input impedance, which minimizes the current draw from the input source, and their ability to operate at high speeds. N-channel MOSFETs, like the 2N7002LT1G, conduct when a positive voltage is applied to the gate relative to the source, making them suitable for a variety of applications including power management, load switching, and signal amplification.
When selecting a MOSFET for a specific application, important parameters to consider include the drain-source voltage (VDSS), drain current (ID), on-state resistance (RDS(on)), and thermal characteristics. The VDSS rating indicates the maximum voltage the MOSFET can block when off, while the ID rating provides the maximum current it can conduct when on. The RDS(on) value is critical for power efficiency, as lower values result in less power dissipation. Thermal characteristics, such as junction-to-ambient thermal resistance (RθJA), are also important for ensuring the device operates within safe temperature limits.
In addition to these parameters, the switching characteristics of the MOSFET, such as turn-on and turn-off times, are crucial for applications requiring fast switching speeds. The body-diode characteristics, which describe the behavior of the intrinsic diode between the drain and source, are relevant for applications involving reverse current flow. Overall, the selection of a MOSFET should be based on a comprehensive evaluation of its electrical and thermal performance to meet the specific requirements of the intended application.