The recommended PCB layout for optimal thermal performance involves placing a thermal pad on the bottom of the package, connecting it to a large copper area on the PCB, and using multiple vias to dissipate heat to the other layers. A minimum of 2oz copper thickness is recommended.
To ensure stability and prevent oscillation, it's essential to follow the recommended layout and component placement guidelines, use a sufficient output capacitor, and add a compensation capacitor (if necessary) as specified in the datasheet. Additionally, minimize the distance between the regulator and the output capacitor, and use a low-ESR capacitor.
Although the datasheet specifies a maximum input voltage of 15V, it's recommended to limit the input voltage to 12V to ensure reliable operation and prevent damage to the device. Applying voltages above 12V may reduce the device's lifespan or cause it to fail prematurely.
The AP78L08SG-13 is rated for operation up to 125°C, but its performance and reliability may degrade at higher temperatures. If your design requires operation above 105°C, consider using a heat sink or a thermally enhanced package to ensure reliable operation. Always follow the recommended operating conditions and derate the device accordingly.
To calculate the power dissipation, use the formula Pd = (Vin - Vout) x Iout. Then, use the thermal resistance (RθJA) specified in the datasheet to calculate the junction temperature (Tj) using the formula Tj = Tc + (Pd x RθJA), where Tc is the case temperature. Ensure that the calculated junction temperature does not exceed the maximum rated value.
AP78L08SG-13 datasheet
by Diodes Incorporated
