06489

April 16, 2012

Rev: C

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Enpirion 2011 all rights reserved, E&OE

Design Considerations for Lead

Exposed Metal on Bottom of Package

Lead-frames offer many advantages in

overall foot print. However, they do require some special considerations.

In the assembly process lead frame construction requires that, for mechanical support, some of the lead

cantilevers be exposed at the point where wire

small pads being exposed on the bottom of the package, as shown in

Only the thermal pad and the perimeter pads are to be mechanically or e

The PCB top layer under the EN6360QI should be clear of any metal (copper pours, traces, or vias) except for

the thermal pad. The “shaded-out” area in

the top layer of the PCB. Any layer 1 metal under the

connections even if it is covered by soldermask.

The solder stencil aperture should be sma

causing bridging between adjacent pins or other exposed metal under the package. Please consult the

Enpirion Manufacturing Application Note for more details and recommendations.

Figure 11

Shaded area highlights exposed metal that is not to be mechanically or electrically connected to the PCB.

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Design Considerations for Lead-Frame Based Modules

Exposed Metal on Bottom of Package

frames offer many advantages in thermal performance, in reduced electrical lead resistance, and in

overall foot print. However, they do require some special considerations.

In the assembly process lead frame construction requires that, for mechanical support, some of the lead

ilevers be exposed at the point where wire-bond or internal passives are attached. This results in several

small pads being exposed on the bottom of the package, as shown in Figure 11.

Only the thermal pad and the perimeter pads are to be mechanically or electrically connected to the PC board.

The PCB top layer under the EN6360QI should be clear of any metal (copper pours, traces, or vias) except for

out” area in Figure 11 represents the area that should be clear of any metal on

the top layer of the PCB. Any layer 1 metal under the shaded-out area runs the risk of undesirable shorted

connections even if it is covered by soldermask.

perture should be smaller than the PCB ground pad. This will prevent excess solder from

causing bridging between adjacent pins or other exposed metal under the package. Please consult the

Enpirion Manufacturing Application Note for more details and recommendations.

11: Lead-Frame exposed metal (Bottom View)

area highlights exposed metal that is not to be mechanically or electrically connected to the PCB.

EN6360QI

thermal performance, in reduced electrical lead resistance, and in

In the assembly process lead frame construction requires that, for mechanical support, some of the lead-frame

bond or internal passives are attached. This results in several

lectrically connected to the PC board.

The PCB top layer under the EN6360QI should be clear of any metal (copper pours, traces, or vias) except for

represents the area that should be clear of any metal on

out area runs the risk of undesirable shorted

ller than the PCB ground pad. This will prevent excess solder from

causing bridging between adjacent pins or other exposed metal under the package. Please consult the

area highlights exposed metal that is not to be mechanically or electrically connected to the PCB.