原创 开关电源Layout ADP2102

?  Use separate analog and power ground planes. Connect the ground reference of sensitive analog circuitry, such as output voltage divider components, to analog ground. In addition, connect the ground references of power components, such as input and output capacitors, to power ground. Connect both ground planes to the exposed pad of the ADP2102.

?  Place the input capacitor as close to the PVIN pin as possible and connect the other end to the closest power ground plane.

?  For low noise and better transient performance, a filter is recommended between PVIN and AVIN. Place the 0.1 μF, 10 Ω low-pass input filter between the AVIN pin and the PVIN pin, as close to AVIN as possible; or the AVIN pin can be bypassed with a ≥1 pF capacitor to the nearest GND plane.

?  Ensure that the high current loops are as short and as wide as possible. Make the high current path from CIN through L, COUT, and the PGND plane back to CIN as short as possible. To accomplish this, ensure that the input and output capacitors share a common PGND plane. In addition, make the high current path from the PGND pin through L and COUT back to the PGND plane as short as possible. To do this, ensure that the PGND pin of the ADP2102 is tied to the PGND plane as close as possible to the input and output capacitors.

?  Place the feedback resistor divider network as close as possible to the FB pin to prevent noise pickup. Try to minimize the length of trace connecting the top of the feedback resistor divider to the output while keeping away from the high current traces and the switch node (LX) that can lead to noise pickup. To reduce noise pickup, place an analog ground plane on either side of the FB trace and make it as small as possible to reduce the parasitic capacitance pickup.

Cin，Cou，L，Bootstrap电容，FB分压电阻都尽量靠近。

AGND和PGND在exposed pad处连接

红色的大电流loop应该尽量小。

FB 返回电压取自Vout，Cout之后。它的路径可以很长，但是需要远离LX和大电流路径，周围铺地。