Texas Instruments provides a recommended PCB layout in the datasheet, but it's also important to follow general best practices for high-frequency PCB design, such as using a solid ground plane, minimizing trace lengths, and using vias to connect signals to the ground plane.
To ensure stability, make sure to follow the recommended compensation network and component values, and also consider the output capacitor selection and PCB layout. Additionally, simulate the design using tools like SPICE or TI's WEBENCH to verify stability.
While the datasheet specifies a maximum input voltage of 15V, it's recommended to derate the input voltage to 12V to ensure reliable operation and to prevent damage to the device.
The LMR62014XMFE is rated for operation up to 125°C, but it's essential to consider the thermal design and ensure proper heat sinking to prevent overheating. Also, be aware that high temperatures can affect the device's performance and reliability.
Start by verifying the input voltage, output load, and PCB layout. Check for any signs of overheating, and ensure that the device is properly soldered and connected. Use oscilloscopes and other diagnostic tools to identify the root cause of the issue, and consult the datasheet and application notes for guidance.