EV1380QI Datasheet, PDF (16/18 Pages) Enpirion, Inc. – 8a synchronous highly integrated dc-dc

Design Considerations
Exposed Metal on Bottom of Package
Package lead frames offer advantages in
thermal performance, in reduced electrical lead
resistance, and in overall foot print. They do,
however, require some special considerations.
In the assembly process, lead-frame
construction requires-for mechanical support-
that some of the lead-frame cantilevers be
exposed at the point where wire-bonds or
internal passives are attached. Because of this
EV1380 Datasheet
lead frame requirement, several small pads are
exposed on the bottom of the package. Only
the large thermal pad and the perimeter pads
should be mechanically or electrically
connected to the PC board. The PCB top layer
under the EV1380QI should be clear of any
metal except for the large thermal pad. The
“grayed-out” area in Figure 10 represents the
area that should be clear of all metal (traces,
vias, or planes) on the top layer of the PCB.
Figure 10: Lead-Frame Exposed Metal. Gray area highlights exposed metal below which there
should not be any metal (traces, vias, or planes) on the top layer of the PCB
08888
16
March 18, 2015
www.altera.com/enpirion
Rev C