Onsemi MBRA1H100T3G 100V Schottky Barrier Rectifier: Datasheet, Application Notes, and Circuit Design Guidelines

The Onsemi MBRA1H100T3G is a highly efficient Schottky Barrier Rectifier designed for high-frequency switching power supplies and other applications where low forward voltage drop and fast switching are critical. This surface-mount device (SMB package) offers a low forward voltage drop of just 0.55V (typical at 1A) and a high current capability of 1A with a repetitive peak reverse voltage of 100V. Its Schottky barrier design inherently provides extremely fast switching performance, which minimizes switching losses and improves overall system efficiency.

Key Datasheet Parameters

The datasheet for the MBRA1H100T3G highlights several crucial specifications. The maximum average forward rectified current (IO) is 1A at a case temperature of 110°C, derating linearly to zero at 150°C. The device features a low maximum reverse leakage current of 100µA at 25°C and 100V, which increases with temperature but remains manageable for most designs. Its operational and storage junction temperature range is from -65°C to +150°C, ensuring reliability in a wide array of environments. The SMB package offers a compact footprint with good thermal characteristics.

Application Notes

This rectifier is ideally suited for high-frequency DC power conversion circuits. Its primary applications include:

Freewheeling diode in switch-mode power supplies (SMPS), such as buck, boost, and flyback converters.

Polarity protection diode in DC input circuits.

Output rectification in low-voltage, high-current power supplies.

A critical consideration in these applications is thermal management. Despite its low VF, power dissipation (IF(AV) VF) can still generate significant heat, especially under high load conditions. Proper PCB layout with adequate copper pour acting as a heat sink is essential to keep the junction temperature within safe limits.

Circuit Design Guidelines

1. Snubber Circuits: While Schottky diodes are generally faster than PN junction diodes, parasitic inductance and capacitance in the circuit can still cause ringing. A small RC snubber network across the diode may be necessary to dampen these oscillations and prevent electromagnetic interference (EMI).

2. Surge Current Protection: Designers must ensure that the inrush or surge currents (e.g., during capacitor charging) do not exceed the device's non-repetitive peak surge current (IFSM) rating of 30A. A fuse or a negative temperature coefficient (NTC) thermistor can be used for protection.

3. Reverse Voltage Margin: Although rated for 100V, it is a best practice to derate the maximum operating voltage. For a 100V part, designing for a maximum of 70-80V in the application provides a safety margin against voltage spikes and transients, enhancing long-term reliability.

4. Thermal Design: Calculate the expected power dissipation (P = IF(AV) VF) and use the device's thermal resistance (RθJA ≈ 75 °C/W for the SMB package on a minimum recommended pad) to estimate the temperature rise above the ambient. Ensure the calculated junction temperature (TJ = TA + (P RθJA)) remains well below the maximum rating of 150°C.

ICGOOODFIND Summary

The Onsemi MBRA1H100T3G Schottky rectifier is a robust and efficient solution for modern power electronics. Its exceptional combination of low forward voltage and fast recovery characteristics makes it a superior choice over standard PN diodes in high-frequency applications, directly contributing to higher efficiency and better thermal performance. Careful attention to thermal management and voltage derating is key to unlocking its full potential and ensuring a reliable design.

Keywords:

Schottky Barrier Rectifier, Low Forward Voltage, Fast Switching, Thermal Management, Power Conversion