With the proviso to locate the controller as close as possible to the MOSFETs to minimize gate driver trace runs, the components related to the analog and feedback signals, current limit setting, and temperature sense are considered in the following:
- Separate power and signal traces, and use a ground plane to provide noise shielding.
- Place all sensitive analog traces and components
such as COMP, FB, RT, ILIM, and SS/TRK away from high-voltage switching
nodes such as SW, HO, LO, or BST to avoid mutual coupling. Use an internal
layer or layers as a ground plane or ground planes. Pay particular attention
to shielding the feedback (FB) trace from power traces and components.
- The upper feedback resistor can be connected directly to the output voltage sense point at the load device or the bulk capacitor at the converter side.
- Connect the ILIM setting resistor from the drain
of the low-side MOSFET to ILIM and make the
connections as close as possible to the LV5144. The trace from
the ILIM pin to the resistor must avoid coupling
to a high-voltage switching net.
- Minimize the loop area from the VCC and VIN pins
through their respective decoupling capacitors to
the GND pin. Locate these capacitors as close as
possible to the LV5144.