A good PCB layout for the LM5122QMHX/NOPB should include a solid ground plane, wide power traces, and a thermal relief pattern under the device to facilitate heat dissipation. TI provides a recommended PCB layout in the datasheet and application notes.
To ensure stability, it's essential to follow the recommended component values and PCB layout guidelines. Additionally, ensure that the output capacitor has a low ESR and is placed close to the output pin. You can also add a small ceramic capacitor (e.g., 10nF) in parallel with the output capacitor to improve stability.
The LM5122QMHX/NOPB can withstand a maximum input voltage of 42V, but it's recommended to operate within the specified input voltage range (up to 36V) for optimal performance and reliability.
The output voltage ripple and noise can be calculated using the equations provided in the datasheet. You'll need to know the output capacitor value, ESR, and the switching frequency. TI also provides a ripple calculator tool to simplify the calculation process.
A low-ESR ceramic capacitor (e.g., X5R or X7R) with a value of 10uF to 22uF is recommended for the input capacitor. This helps to filter out input voltage noise and ensure stable operation.
LM5122QMHX/NOPB datasheet
by Texas Instruments
