Texas Instruments recommends a 2-layer or 4-layer PCB with a solid ground plane on the bottom layer to improve thermal performance. Additionally, keeping the thermal pad connected to the ground plane and using thermal vias can help reduce thermal resistance.
To ensure reliable operation at high temperatures, it's essential to follow the recommended operating conditions, including derating the output current and voltage according to the temperature derating curve. Additionally, using a heat sink and ensuring good airflow can help keep the device within its operating temperature range.
Texas Instruments recommends using a low-ESR ceramic capacitor (X5R or X7R dielectric) with a value between 10uF to 22uF for the input capacitor. This helps to filter out noise and ensure stable operation.
To troubleshoot output voltage regulation issues, check the input voltage, output load, and feedback resistors for correct values and connections. Ensure that the output capacitor is properly sized and connected. Also, verify that the device is not overheating and that the thermal shutdown is not triggered.
The maximum allowed output capacitance for stable operation is 100uF. Exceeding this value can cause instability and oscillations in the output voltage.
PT6905C datasheet
by Texas Instruments
