Texas Instruments recommends a 2-layer PCB with a solid ground plane on the bottom layer and a thermal relief pattern on the top layer to ensure good thermal conductivity. Additionally, keeping the PCB thickness to a minimum (e.g., 0.8 mm) and using a thermal interface material (TIM) between the device and the heat sink can further improve thermal performance.
To ensure reliable operation at high temperatures, it's essential to follow the recommended operating conditions, including the maximum junction temperature (Tj) of 150°C. Additionally, consider using a heat sink with a thermal resistance of ≤ 10°C/W, and ensure good airflow around the device. It's also crucial to follow proper PCB design and layout guidelines to minimize thermal resistance.
The maximum allowed voltage drop across the internal resistance of the PTB78520WAH is approximately 1.5 V. Exceeding this voltage drop can lead to reduced efficiency, increased power losses, and potentially even device failure.
To calculate the power dissipation of the PTB78520WAH, use the following formula: Pd = (Vin - Vout) x Iout, where Vin is the input voltage, Vout is the output voltage, and Iout is the output current. Additionally, consider the device's efficiency, which is typically around 95% for this device.
Texas Instruments recommends using input capacitors with a minimum capacitance of 10 μF and an ESR of ≤ 100 mΩ. For output capacitors, use a minimum capacitance of 22 μF and an ESR of ≤ 50 mΩ. The capacitor selection should also consider the device's operating frequency, output voltage, and current requirements.
PTB78520WAH datasheet
by Texas Instruments
