MOSFET Selection for Power Switching Solutions: STL7N6F7, STD6N80K5 vs. China Alternatives VBQG1620, VBE18R07S
In modern power design, choosing the right MOSFET involves balancing voltage rating, current capability, switching performance, and footprint. This article takes two classic STMicroelectronics MOSFETs—the compact STL7N6F7 and the high-voltage STD6N80K5—as references, and compares them with domestic alternatives VBQG1620 and VBE18R07S from VBsemi. By analyzing their key parameters and design focus, we provide a clear selection guide for your next power switching application.
Comparative Analysis: STL7N6F7 (N-channel) vs. VBQG1620
Original Model (STL7N6F7) Core Analysis:
This is a 60V N-channel MOSFET in a compact DFN-8 (2x2) package. It belongs to ST’s STripFET F7 series, offering a good balance of low on-resistance and moderate current in a small form factor. Key features include a continuous drain current of 7A and a typical on-resistance of 19mΩ (25mΩ max @10V). Its fast switching characteristics and small footprint make it suitable for space-constrained, efficiency-sensitive applications.
Domestic Alternative (VBQG1620) Compatibility and Differences:
VBsemi’s VBQG1620 is a pin-to-pin compatible alternative in a similar DFN6(2x2) package. It matches the 60V voltage rating but offers improved performance: a lower on-resistance of 19mΩ (at 10V) and a higher continuous current rating of 14A. This makes it a performance-enhanced drop-in replacement for the original.
Key Application Areas:
- STL7N6F7: Ideal for compact 48V-60V systems requiring efficient switching, such as:
- DC-DC converters in telecom/industrial boards.
- Load switches and power management in portable equipment.
- Motor drive circuits for small motors.
- VBQG1620: Suitable for the same applications but where higher current capability and lower conduction loss are desired, offering an upgraded solution without board redesign.
Comparative Analysis: STD6N80K5 (N-channel) vs. VBE18R07S
Original Model (STD6N80K5) Core Analysis:
This is an 800V N-channel MOSFET in a TO-252 (DPAK) package, designed for high-voltage off-line applications. It offers a drain current of 4.5A and a gate threshold voltage of 5V. Its robust voltage rating and through-hole compatible surface-mount package make it a reliable choice for medium-power AC-DC and high-voltage switching.
Domestic Alternative (VBE18R07S) Compatibility and Differences:
VBsemi’s VBE18R07S is a direct alternative in the same TO-252 package. It matches the 800V voltage rating but provides enhanced performance: a higher continuous current of 7A and a lower on-resistance of 770mΩ (at 10V). The gate threshold voltage is 3.5V, which may allow for easier drive compatibility in some circuits.
Key Application Areas:
- STD6N80K5: Commonly used in:
- Switch-mode power supplies (SMPS) for AC-DC conversion.
- Power factor correction (PFC) stages.
- Lighting ballasts and industrial controls.
- VBE18R07S: Suitable for the same high-voltage applications but offers higher current handling and lower conduction losses, making it ideal for designs requiring increased power density or efficiency.
Conclusion
This comparison highlights two distinct replacement strategies:
For compact, medium-voltage N-channel applications, the original STL7N6F7 provides a reliable solution in a tiny DFN package. Its domestic alternative VBQG1620 not only maintains package compatibility but also delivers superior on-resistance and higher current capability, making it a performance-upgraded choice for space-constrained designs.
For high-voltage switching needs, the original STD6N80K5 offers a proven 800V solution in a robust TO-252 package. The alternative VBE18R07S enhances key parameters—higher current (7A) and lower on-resistance—providing a stronger performance option for high-voltage power supplies and industrial systems.
The core insight remains: selection depends on precise requirement matching. Domestic alternatives like VBQG1620 and VBE18R07S not only serve as reliable backups but also offer performance advantages, giving engineers greater flexibility in design optimization and cost management. Understanding each device’s parameter profile ensures its full potential is realized in the circuit.