A good PCB layout for optimal thermal performance involves placing the device near a thermal pad or a heat sink, and ensuring good thermal conductivity between the device and the heat sink. A 4-layer PCB with a solid ground plane and a thermal relief pattern can also help to dissipate heat efficiently.
To ensure reliable start-up and shutdown, it is recommended to use a soft-start circuit to limit the inrush current, and to add a delay between power-on and the enable signal. Additionally, a voltage supervisor can be used to ensure that the device is only enabled when the input voltage is within the recommended range.
To ensure EMI and EMC compliance, it is recommended to use a shielded inductor, to keep the switching node (SW) as short as possible, and to use a common-mode choke to reduce common-mode noise. Additionally, a good PCB layout with a solid ground plane and a Faraday shield can help to reduce radiated emissions.
To optimize the device for low standby power consumption, it is recommended to use a low-quiescent-current (Iq) mode, to disable unnecessary blocks, and to use a low-power oscillator. Additionally, using a low-dropout regulator (LDO) with a low quiescent current can also help to reduce standby power consumption.
The key considerations for thermal design and heat sinking include selecting a heat sink with a high thermal conductivity, ensuring good thermal interface material (TIM) between the device and the heat sink, and using a thermal relief pattern on the PCB to improve heat dissipation.
LP3943ISQX/NOPB datasheet
by Texas Instruments
