PCB modular design 23——LDO linear regulated power supply module PCB layout design specification

PCB modular design 23——LDO linear regulated power supply module PCB layout design specification

1. Composition and concept of LDO linear regulated power supply

The LDO linear regulator is the most basic regulated power supply conversion, it can only be used for step-down (such as 3.3V down to 1.8V).
Generally, the LDO is used in a power supply circuit with a current less than 2A. It has the advantages of low cost, simple and easy-to-use circuit, small power supply ripple, relatively stable, and fast power-on.

Second, the main road layout points of the LDO circuit

1. Analyze the main input/output path of the power module, and place it in a straight or L shape when laying out;

2. The capacitors are placed in the order of first large and then small, and the nearest input/output pins;

3. The width of the input/output wiring path and the number of layer-changing vias must meet the size of the power supply current;

4. The vias at the input end are placed in front of the capacitor, the vias at the output end are placed behind the capacitor, and the GND vias are placed near the pins. The number of input, output, and GND vias should be equal;

5. The large GND pad must be drilled to facilitate heat dissipation, and the solder resist window must be opened on the back.

6. The GND of the input/output should be connected together as much as possible to maintain a complete return flow.