STW4141_06 Datasheet, PDF (24/30 Pages) STMicroelectronics – Single-coil dual-output step-down DC/DC converter for digital base band and multimedia processor supply

Application information
STw4141
4.7.1
PCB layout
Figure 16 and Figure 17 show the PCB layout. All components are on the top side of the
board.
Figure 16. Demoboard top layer
Figure 17. Demoboard assembled with 22 µF
output capacitor
4.7.2
TFBGA16 internal bumps access
Pad centers are at 500 µm distance. Pad diameter is 275 µm. The distance between two
adjacent pad edges is only 225 µm. We recommend a distance for lead-out signals from the
center of pad matrix by 75 µm wide trace. Isolation distance in this case is 75 µm (see
Figure 18 and Figure 19).
Figure 18. TFBGA16 ball pad spacing and track parameters to internal pads
Grid dot distance :
with
A = 500µm
B = 275µm
C = 75µm
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