The MBR4045PT is a dual-chip, center-tap Schottky barrier power rectifier diode housed in a heavy-duty TO-247 (TO-3P / SOT-93 compatible) through-hole package. Utilizing advanced Schottky barrier technology with platinum barrier metal, the MBR4045PT features a repetitive peak reverse voltage rating of 45V, a total continuous forward current rating of 40A (20A per diode leg), an ultra-low forward voltage drop (V_F), and negligible reverse recovery switching losses. It is widely used in high-efficiency switch-mode power supplies (SMPS), low-voltage DC-DC converters, solar charge controllers, OR-ing power diodes, and freewheeling clamp circuits.

Specifications

• Brand / Manufacturer: ON Semiconductor / Vishay / Diodes Inc. / Industry Standard
• Part Number / Marking: MBR4045PT / B4045
• Diode Configuration: Dual Common Cathode (Center Tap)
• Maximum Repetitive Peak Reverse Voltage (V_RRM): 45V
• Working Peak Reverse Voltage (V_RWM): 45V
• Maximum DC Blocking Voltage (V_R): 45V
• Average Rectified Forward Current (I_F(AV)): 40A Total (20A per Diode Leg at T_C = 125°C)
• Peak Repetitive Forward Current (I_FRM): 40A per leg (Rated V_R, Square Wave, 20kHz at T_C = 90°C)
• Non-Repetitive Peak Forward Surge Current (I_FSM): 400A (8.3ms single half sine-wave)
• Maximum Instantaneous Forward Voltage (V_F): < 0>F = 20A, T_J = 25°C) / < 0>F = 20A, T_J = 125°C)
• Maximum Reverse Leakage Current (I_R): 1.0mA @ T_J = 25°C / 50mA @ T_J = 125°C (at rated V_R)
• Maximum Thermal Resistance, Junction-to-Case (R_θJC): 1.4°C/W
• Operating Junction & Storage Temperature Range: -65°C to +175°C
• Package / Case: TO-247 / SOT-93 / TO-3P (Pin 1: Anode 1, Pin 2: Common Cathode / Tab, Pin 3: Anode 2)

Features

• Ultra-Low Forward Voltage Drop: Reduces conduction losses significantly, enhancing overall energy efficiency and reducing heatsink size in low-voltage power rails.
• Extremely Fast Switching Speed: Majority carrier conduction mechanism eliminates minority carrier storage time, ensuring virtually zero reverse recovery switching losses.
• Dual Center-Tap Configuration: Integrates two balanced 20A Schottky diodes with a shared cathode to simplify full-wave secondary output rectification.
• High Surge Capability: Handles non-repetitive peak surge currents up to 400A during startup and transient load conditions.
• High Junction Operating Temperature (175°C): Guard-ring stress protection provides high thermal stability and protection against transient over-voltage stress.
• Heavy-Duty TO-247 Package: Large thermal mounting tab enables direct bolting to heatsinks for high-current thermal management.

Common Applications

• High-Efficiency SMPS Secondary Rectification: Secondary output rectification in 3.3V, 5V, and 12V ATX power supplies, server power supplies, and battery chargers.
• Solar Charge Controllers & MPPT Units: Low-loss anti-reverse power blocking and solar panel output rectification.
• Power OR-ing & Redundancy Diodes: Seamless battery backup switching and dual power supply OR-ing with minimal voltage drop.
• High-Current DC-DC Buck Converters: Catch / freewheeling diode stage in high-power step-down voltage regulators.
• Reverse Polarity Protection: High-current, low-forward-drop reverse voltage blocking on DC input power rails.

Usage Tips

• Heatsink Mounting: Always bolt the TO-247 tab securely to an aluminum heatsink using thermal paste. If the heatsink is tied to chassis ground, use an insulating silicone/mica pad and bushing (Pin 2 and the mounting tab are internally connected to the Common Cathode).
• Parallel Leg Operation: To utilize the full 40A continuous capacity in single-channel circuits, connect Pin 1 (Anode 1) and Pin 3 (Anode 2) together in parallel on the PCB.
• Reverse Leakage Consideration: Schottky diodes exhibit increased reverse leakage current at elevated temperatures (up to 50mA at 125°C); ensure adequate cooling to prevent thermal runaway.
• Voltage Spike Clamping: Keep the operating reverse voltage within 80% of the 45V rating, and place a small RC snubber across each diode leg to absorb high-frequency inductive voltage spikes from transformer leakage inductance.

Datasheet