STP24N65M2

The STMicroelectronics STP24N65M2 is an N-channel Power MOSFET based on STMicroelectronics MDmesh M2 technology, designed for high-voltage, high-efficiency switching applications in offline power conversion systems. It is optimized for low conduction losses and reduced switching losses, enabling improved efficiency in hard-switching and resonant topologies typically used in switch-mode power supplies and power factor correction stages. The device integrates a high breakdown voltage capability with relatively low on-resistance, making it suitable for power circuits operating directly from rectified mains voltage.

## Device Function and Technology Platform

The STP24N65M2 is an enhancement-mode N-channel MOSFET fabricated using STMicroelectronics’ MDmesh M2 superjunction technology. This structure combines vertical MOSFET conduction with charge-balanced superjunction architecture, allowing a significant reduction in on-state resistance without compromising high-voltage blocking capability. The device is intended for use as a primary switching element in offline AC-DC converters, DC-DC converters, and energy conversion stages where both efficiency and voltage robustness are required.

The MOSFET operates in enhancement mode, meaning it is normally off when gate-to-source voltage is zero and requires a positive gate voltage to form a conductive channel. The device is optimized for fast switching operation, with reduced gate charge and improved reverse recovery behavior compared to conventional planar MOSFET technologies.

## Absolute Maximum Ratings and Electrical Limits

The STP24N65M2 is rated for a drain-source voltage (VDS) of 650 V, which defines its maximum repetitive blocking capability in off-state conditions. This makes it suitable for offline applications connected to rectified universal AC mains with adequate design margin.

The continuous drain current (ID) is specified under defined thermal conditions and is dependent on case temperature and PCB thermal design. The device supports both continuous and pulsed drain current operation, with pulsed current capability significantly higher than steady-state limits due to the intrinsic thermal inertia of the silicon die and package.

The gate-source voltage (VGS) is typically limited to ±20 V, defining the maximum allowable voltage applied across the gate oxide to prevent dielectric breakdown. Avalanche energy capability (EAS) is specified in the datasheet and represents the device’s ability to absorb inductive energy during unclamped switching events without failure. Safe operating area (SOA) curves further define the simultaneous voltage-current-time boundaries under switching and linear-mode stress conditions.

The maximum junction temperature (TJ) is typically rated up to 150 °C, and storage temperature range extends beyond normal operating conditions to ensure robustness during assembly and handling.

## Static Electrical Characteristics

The STP24N65M2 exhibits low on-state resistance (RDS(on)), which is a key performance parameter for conduction loss minimization. This resistance is specified at defined gate-source voltages (typically 10 V) and junction temperatures, with higher values observed at elevated temperatures due to positive thermal coefficient behavior inherent to MOSFET conduction channels.

Gate threshold voltage (VGS(th)) defines the minimum gate-to-source voltage required to initiate channel formation. This parameter is characterized at low drain current levels and does not represent full enhancement conditions.

Drain-source leakage current (IDSS) is specified under high-voltage blocking conditions and is typically very low, reflecting the high quality of the superjunction structure and junction isolation design.

## Dynamic and Switching Characteristics

The switching performance of the STP24N65M2 is defined by parameters such as total gate charge (Qg), input capacitance (Ciss), output capacitance (Coss), and reverse transfer capacitance (Crss). These parameters directly influence switching speed, gate driver requirements, and overall switching losses.

Total gate charge represents the total charge required to transition the device from off-state to fully enhanced conduction. Lower gate charge contributes to reduced driver losses and improved efficiency in high-frequency switching applications.

Capacitance parameters are voltage-dependent and influence both turn-on and turn-off behavior. The reverse transfer capacitance (Miller capacitance) is particularly important in determining dv/dt sensitivity and switching stability in half-bridge and full-bridge topologies.

Switching energy losses are characterized through turn-on and turn-off energy parameters measured under standardized test conditions with defined inductive loads. These values are critical for thermal modeling in high-frequency converters.

## Thermal Characteristics and Package Structure

The STP24N65M2 is typically offered in a TO-220 or similar through-hole power package optimized for thermal conduction to external heatsinks. The thermal resistance from junction to case (RθJC) and junction to ambient (RθJA) define the device’s ability to dissipate heat under operating conditions.

Efficient thermal design requires direct mounting to heatsinks with appropriate thermal interface materials to minimize thermal resistance. The package structure is designed to provide a low-resistance thermal path from silicon die to mounting surface, ensuring stable operation under high-power switching conditions.

The device’s thermal behavior is strongly influenced by PCB layout, heatsinking strategy, and switching frequency, as both conduction and switching losses contribute to total junction temperature rise.

## Body Diode Characteristics

The intrinsic body diode of the STP24N65M2 is an important element in many switching topologies. It provides a freewheeling path for inductive current when the MOSFET is in off-state. The diode exhibits reverse recovery behavior characterized by reverse recovery time (trr) and reverse recovery charge (Qrr), which are key parameters in hard-switching applications.

In superjunction MOSFETs such as this device, body diode performance is generally optimized for reduced reverse recovery losses compared to older planar structures, but it is still not equivalent to dedicated fast recovery diodes in ultra-high-frequency rectification applications.

## Typical Application Domains

The STP24N65M2 is primarily used in offline power conversion systems, including switch-mode power supplies (SMPS), where it serves as a primary switching transistor in flyback, forward, and resonant converter topologies. It is also widely used in power factor correction (PFC) circuits, where high voltage blocking capability and efficient switching performance are required.

Additional applications include LED lighting drivers, industrial power supplies, battery chargers, and auxiliary power supply circuits in consumer and industrial electronics. Its combination of high voltage rating and optimized switching characteristics makes it suitable for universal input AC systems and high-efficiency energy conversion stages.

## Conduction and Switching Loss Considerations

Device performance in real circuits is governed by the trade-off between conduction losses, dominated by RDS(on), and switching losses, influenced by capacitance and gate charge parameters. The MDmesh M2 structure is specifically engineered to reduce the figure of merit (RDS(on) × Qg), enabling improved efficiency at medium-to-high switching frequencies.

Thermal design must account for both static conduction dissipation and dynamic switching energy dissipation, especially in hard-switched topologies where voltage and current overlap during transitions contribute significantly to total power loss.

## Conclusion

The STMicroelectronics STP24N65M2 is a high-voltage N-channel MOSFET built on MDmesh M2 superjunction technology, optimized for efficient power conversion in offline and industrial switching applications. With a 650 V drain-source rating, low on-resistance, and reduced switching losses, it is designed for high-efficiency SMPS, PFC stages, and power management systems. Its electrical and thermal characteristics are balanced to support high-voltage operation with controlled conduction and switching performance, making it a suitable component for modern energy-efficient power electronics architectures.