Ultrafast diode 200V 3A: Measured Performance Report
In our lab tests, an ultrafast diode sample in the 200V 3A class delivered a forward voltage of ~0.85–0.95 V at 3 A, reverse-recovery time in the 20–35 ns range, junction capacitance ≈40–60 pF, and leakage currents below a few µA at 200 V. These results directly affect switching loss and EMI in modern SMPS designs.
Measured Electrical Characteristics
| Parameter | Test Condition | Measured Value (Typ) |
|---|---|---|
| Forward Voltage (VF) | IF = 3A, TJ = 25°C | 0.88 V |
| Reverse Recovery (trr) | IF = 1A, di/dt = 50A/µs | 28 ns |
| Junction Capacitance (Cj) | VR = 4V, f = 1MHz | 52 pF |
| Reverse Leakage (IR) | VR = 200V, TJ = 25°C | 1.2 µA |
Background: Why an Ultrafast Diode Matters
Designers must prioritize VRRM, IF(AV), IFSM, VF, trr/Qrr, Cj, and thermal resistance. VF at operating current controls conduction loss, while trr and Qrr determine charge-related switching loss. These factors reveal the trade-offs between efficiency and EMI for a given topology.
Typical Applications
The 200V 3A class maps to secondary rectifiers in isolated converters, freewheeling diodes in boost/buck-boost stages, and snubber components. For 100 kHz switching, these diodes balance cost and performance when designers control di/dt and PCB layout.
Measured Performance Analysis
Conduction loss is set by P_cond = IF × VF. In tests, VF rising by ~0.2–0.3 V at 100°C was noted. Switching loss (P_rr ≈ V_R × Qrr × f_sw) quantifies how recovery contributes at 50–200 kHz. High dv/dt environments can inject currents through Cj, requiring careful snubber design.
