The following PCB layout design guidelines are recommended:
- Place the input decoupling caps from
VIN to GND, SYS (A5) to GND, and SYS (F5) to GND close to the IC with wide and short
traces. The input decoupling caps from SYS (A5) to GND and from SYS (F5) to GND are
required.
- Place the output caps from BBOUT to
GND, SYS to GND, BAT to GND, LSLDO1 to GND, and LSLDO2 to GND close to the IC with wide
and short traces.
- All SYS pins must be connected with a wide trace for strong connection.
- 2nd layer should be the
ground layer for strong ground connection with vias for all the GND connections,
especially for BKGND, BBGND, and all the input/output caps' GND connections. Avoid
routing which can intterupt or cut the ground planes.
- The Buck output voltage feedback from
Buck output cap to BKOUT should be realized with an independent trace with no current
flow. This feedback line is a sensitive, high impedance line and should be routed away
from noisy components and traces (for example, switch nodes of Buck and Buck-boost) or
other noise sources.
- The power (high current) paths traces must be sized appropriately for the maximum
charge current in order to avoid large voltage drops on these traces.