IR21531STRPBF datasheet by International Rectifier

IR21531STRPBF Frequently Asked Questions (FAQs)

• What is the recommended PCB layout for optimal performance?
  The recommended PCB layout for the IR21531STRPBF involves keeping the high-frequency switching nodes (e.g., pins 3 and 4) as small as possible, using a solid ground plane, and placing the bootstrap capacitor (CBOOT) close to the IC. Additionally, it's essential to minimize the length of the traces connecting the IC to the power MOSFETs and to use a low-impedance path for the high-current signals.
• How do I choose the right bootstrap capacitor (CBOOT) value?
  The bootstrap capacitor (CBOOT) value depends on the specific application and the switching frequency. A general guideline is to choose a capacitor with a value between 10nF to 100nF. A larger capacitor value can provide a more stable voltage supply to the high-side driver, but it may also increase the IC's power consumption. It's recommended to consult the application notes and evaluate the trade-offs for the specific design.
• What is the maximum allowed voltage on the VCC pin?
  The maximum allowed voltage on the VCC pin is 20V, according to the datasheet. However, it's recommended to keep the voltage below 18V to ensure reliable operation and to prevent damage to the IC. Exceeding the maximum voltage can lead to IC failure or reduced lifespan.
• Can I use the IR21531STRPBF with a different power MOSFET than the recommended ones?
  While it's possible to use the IR21531STRPBF with a different power MOSFET, it's essential to ensure that the chosen MOSFET meets the recommended specifications, such as the gate-source voltage rating, gate charge, and on-resistance. Using a non-recommended MOSFET may affect the IC's performance, reliability, or even lead to IC failure. It's recommended to consult the application notes and evaluate the compatibility of the chosen MOSFET with the IR21531STRPBF.
• How do I handle the dead time between the high-side and low-side switches?
  The IR21531STRPBF has a built-in dead time generator that ensures a minimum dead time of 100ns between the high-side and low-side switches. However, the actual dead time may vary depending on the specific application and the chosen components. It's essential to ensure that the dead time is sufficient to prevent shoot-through currents and to minimize losses. The dead time can be adjusted by adding external components, such as resistors and capacitors, to the IC's dead time generator circuit.