A good PCB layout for the BD235 should include a large copper area for heat dissipation, with multiple vias connecting the top and bottom layers. The device should be placed near a thermal pad or a heat sink to improve heat dissipation.
The input capacitor should be chosen based on the input voltage ripple requirement and the output voltage regulation. A ceramic capacitor with a value between 1uF to 10uF is recommended, with a voltage rating higher than the maximum input voltage.
The maximum output current capability of the BD235 is 3.5A, but it can be limited by the thermal performance of the device and the PCB layout. It's recommended to derate the output current based on the ambient temperature and the device's thermal performance.
To ensure the stability of the BD235 output voltage, it's recommended to use a minimum output capacitance of 10uF, with a low ESR (Equivalent Series Resistance) and a voltage rating higher than the output voltage. Additionally, the output voltage should be monitored and adjusted as needed to prevent oscillations.
The recommended input voltage range for the BD235 is 4.5V to 18V, but it can operate with an input voltage as low as 3.5V. However, the device's performance and efficiency may be affected at lower input voltages.
BD235 datasheet
by STMicroelectronics
