isl8560 Intersil Corporation, isl8560 Datasheet - Page 16

• Manufacturer Part Number: isl8560
• Description: Dc/dc Power Switching Regulator
• Manufacturer: Intersil Corporation

ISL8560
A multi-layer printed circuit board is recommended.
Figure 32 shows the connections of the critical components
in the converter. Note that capacitors C
and C
could
IN
OUT
each represent numerous physical capacitors. Dedicate one
solid layer, usually a middle layer of the PC board, for a
ground plane and make all critical component ground
connections with vias to this layer. Dedicate another solid
layer as a power plane and break this plane into smaller
islands of common voltage levels. Keep the metal runs from
the LX terminals to the output inductor short. The power
plane should support the input power and output power
nodes. Use copper filled polygons on the top and bottom
circuit layers for the LX nodes. Use the remaining printed
circuit layers for small signal wiring.
In order to dissipate heat generated by the internal LDO and
other power components, the ground pad at the bottom of
the device should be connected to the ground plane through
at least nine vias. This allows the heat to move away from
the IC and also ties the pad to the ground plane through a
low impedance path.
The switching components should be placed close to the
ISL8560 first. Minimize the length of the connections
between the input capacitors, C
. Make the PGND and the
IN
output capacitors as short as possible.
NOTE: It is recommended that any applications with input
voltage greater than 30VDC should be polymer coated to
meet Intersil’s IPC-2221 creepage and clearance
specification.
16
FN9244.6
September 18, 2007