Dual P-Channel 2.5V Specified PowerTrench TM MOSFET# FDS6875 Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The FDS6875 is a dual N-channel PowerTrench® MOSFET specifically designed for high-efficiency power management applications. Its primary use cases include:
DC-DC Converters
- Synchronous buck converters for voltage regulation
- Low-side switching in half-bridge configurations
- Point-of-load (POL) converters in distributed power systems
- Voltage regulator modules (VRMs) for processor power delivery
Power Switching Applications
- Motor drive circuits in automotive systems
- Solid-state relay replacements
- Battery protection circuits
- Hot-swap power controllers
Load Management
- Power distribution switches
- OR-ing controllers for redundant power supplies
- Load disconnect circuits
### Industry Applications
Computing and Telecommunications
- Server power supplies and motherboard VRMs
- Network equipment power management
- Base station power systems
- Data center power distribution units
Automotive Electronics
- Electronic control unit (ECU) power management
- LED lighting drivers
- Infotainment system power supplies
- Advanced driver assistance systems (ADAS)
Consumer Electronics
- Gaming console power systems
- High-end audio amplifier power stages
- LCD/LED TV power management
- Portable device charging circuits
### Practical Advantages and Limitations
Advantages
- Low RDS(ON) : 9.5mΩ maximum at VGS = 10V enables high efficiency operation
- Fast Switching : Typical rise time of 15ns and fall time of 20ns reduces switching losses
- Thermal Performance : Low thermal resistance (RθJC = 1.0°C/W) supports high power density designs
- Dual Configuration : Two independent MOSFETs in single package saves board space
- Avalanche Rated : Robustness against voltage transients and inductive load switching
Limitations
- Gate Charge : Total gate charge of 30nC requires careful gate driver selection
- Voltage Rating : 30V maximum limits use in higher voltage applications
- Package Constraints : SO-8 package thermal limitations in very high current applications
- Parasitic Capacitance : CISS of 1800pF may cause gate drive challenges at very high frequencies
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Gate Drive Issues
- Pitfall : Insufficient gate drive current causing slow switching and excessive losses
- Solution : Use dedicated gate driver ICs capable of delivering 2-3A peak current
- Pitfall : Gate oscillation due to layout parasitics
- Solution : Implement series gate resistors (2-10Ω) and minimize gate loop area
Thermal Management
- Pitfall : Inadequate heatsinking leading to thermal runaway
- Solution : Use thermal vias, adequate copper area, and consider external heatsinks for currents >15A
- Pitfall : Poor thermal coupling between dual MOSFETs
- Solution : Ensure symmetrical layout and thermal relief for both devices
PCB Layout Recommendations
Power Path Layout
- Use thick copper traces (≥2oz) for high current paths
- Minimize loop area in switching circuits to reduce EMI
- Place input and output capacitors close to MOSFET terminals
- Implement star grounding for power and signal grounds
Gate Drive Layout
- Keep gate drive traces short and direct
- Route gate traces away from switching nodes
- Use ground plane for return paths
- Place gate resistors close to MOSFET gates
Thermal Management
- Use thermal relief patterns for solder joint reliability
- Implement multiple thermal vias under the package
- Provide adequate copper area for heat spreading
- Consider exposed pad connection to internal ground plane
### Compatibility Issues
Gate Driver Compatibility
- Compatible with most standard gate driver ICs
