A good PCB layout for optimal thermal performance would involve placing thermal vias under the IC, using a solid ground plane, and keeping the thermal traces as short and wide as possible. It's also recommended to use a thermal pad on the bottom of the IC.
To ensure stability, make sure to follow the recommended component values and layout guidelines in the datasheet. Additionally, use a low-ESR output capacitor, and consider adding a small ceramic capacitor in parallel with the output capacitor to improve stability.
Although the datasheet specifies a maximum input voltage of 18V, it's recommended to derate the input voltage to 15V to ensure reliable operation and to prevent damage to the IC.
The output voltage ripple can be calculated using the formula: ΔVout = (Iout * ESL) / (Cout * fsw), where Iout is the output current, ESL is the equivalent series inductance of the output capacitor, Cout is the output capacitance, and fsw is the switching frequency.
The AP3154AFG-7 is rated for operation up to 125°C, but it's recommended to derate the output current and input voltage at high temperatures to ensure reliable operation. Consult the datasheet for more information on thermal derating.
AP3154AFG-7 datasheet
by Diodes Incorporated
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