Texas Instruments provides a recommended PCB layout in the LM3658SD evaluation module documentation, which includes guidelines for component placement, thermal management, and routing. Following this layout can help ensure optimal performance and minimize electromagnetic interference (EMI).
The input capacitor selection depends on the input voltage, output voltage, and output current requirements. A general rule of thumb is to choose a capacitor with a voltage rating at least 1.5 times the maximum input voltage, and a capacitance value that ensures the input ripple voltage is within the recommended range (typically 1-2% of the input voltage).
While the datasheet specifies an operating junction temperature range of -40°C to 125°C, the maximum ambient temperature for reliable operation depends on the specific application and thermal management. As a general guideline, the ambient temperature should be kept below 85°C to ensure reliable operation and minimize thermal-related failures.
To ensure EMC compliance, follow the recommended PCB layout and component placement guidelines, use a shielded inductor, and add EMI filters (such as common-mode chokes and capacitors) as needed. Additionally, consider using a metal shield or enclosure to contain radiated emissions.
The recommended output capacitor type is a low-ESR ceramic or polymer capacitor, with a value that depends on the output voltage and current requirements. A general guideline is to choose a capacitor with a capacitance value of at least 10 μF for every 1 A of output current, and a voltage rating at least 1.5 times the output voltage.
LM3658SD datasheet
by Texas Instruments
