Plastic High-Efficiency Rectifiers Reverse Voltage 50 to 1000V Forward Current 1.0A # Technical Documentation: HER107G Fast Recovery Rectifier Diode
## 1. Application Scenarios
### 1.1 Typical Use Cases
The HER107G is a 1A, 1000V fast recovery rectifier diode designed for high-frequency switching applications where rapid reverse recovery is critical. Key use cases include:
- Switching Mode Power Supplies (SMPS) : Used in flyback, forward, and bridge rectifier configurations in AC-DC converters operating at frequencies from 20kHz to 100kHz
- Freewheeling/Clamping Circuits : Provides protection for switching transistors (MOSFETs/IGBTs) by clamping voltage spikes in inductive load applications
- Output Rectification : In DC-DC converters and inverter output stages where efficiency at higher frequencies is paramount
- Snubber Circuits : Dissipates energy from parasitic inductances to protect sensitive components
### 1.2 Industry Applications
- Consumer Electronics : LCD/LED TV power supplies, computer ATX power supplies, adapters/chargers
- Industrial Equipment : Motor drives, welding equipment, UPS systems
- Renewable Energy : Solar microinverters, wind turbine control circuits
- Automotive Electronics : DC-DC converters in electric/hybrid vehicles (secondary circuits)
- Lighting : LED driver circuits, HID ballasts
### 1.3 Practical Advantages and Limitations
Advantages:
- Fast Recovery Time : Typical trr = 75ns reduces switching losses significantly compared to standard rectifiers
- High Voltage Rating : 1000V repetitive peak reverse voltage (VRRM) provides margin for voltage spikes
- Low Forward Voltage : VF = 1.3V max at 1A reduces conduction losses
- Glass Passivated Junction : Provides stable performance and reliability under varying environmental conditions
- Compact DO-41 Package : Industry-standard through-hole package for easy assembly and thermal management
Limitations:
- Current Handling : Limited to 1A average forward current, requiring parallel configurations for higher current applications
- Thermal Considerations : Maximum junction temperature of 150°C necessitates proper heatsinking in high-power applications
- Reverse Recovery Charge : While improved over standard diodes, still generates EMI that requires filtering in sensitive circuits
- Voltage Derating : Recommended to operate at ≤80% of VRRM for reliability in high-temperature environments
## 2. Design Considerations
### 2.1 Common Design Pitfalls and Solutions
Pitfall 1: Inadequate Thermal Management
- Problem : Junction temperature exceeds 150°C during continuous operation at full load
- Solution : Calculate thermal resistance (RθJA ≈ 100°C/W for DO-41 without heatsink) and implement:
- Proper PCB copper area (≥100mm² for natural convection)
- External heatsinks for high ambient temperatures
- Derating current above 75°C ambient
Pitfall 2: Voltage Overshoot During Switching
- Problem : Parasitic inductance causes voltage spikes exceeding VRRM during reverse recovery
- Solution : Implement RC snubber networks across the diode with values calculated using:
```
Rsnubber = √(Lparasitic / (C * 0.5 * trr))
Csnubber = (Irr * trr) / (2 * ΔV)
```
Pitfall 3: EMI Generation from Fast Switching
- Problem : High di/dt during reverse recovery creates electromagnetic interference
- Solution :
- Use ferrite beads in series with the diode
- Implement proper grounding and shielding
- Add small capacitors (100pF-1nF) in parallel for high-frequency bypass
### 2.2 Compatibility Issues with Other Components
With
