Analog Integrated Circuit Device Data

Freescale Semiconductor

13

34710

TYPICAL APPLICATIONS

This layout provides the lowest possible impedance as

well as lowest possible dc resistance for the power routing.

Note that the power path and its return should be placed, if

possible, on top of each other on different layers or opposite

sides of the pcb.

Small ceramic capacitors are placed in parallel with the

Aluminum electrolytics so that the overall bulk filtering

presents a low ESL to the high di/dt switching currents.

Alternatively, special low ESL/ESR switching-grade

electrolytics may be used.

An additional feature of the MC34710 is the 32 SOICW-EP

exposed pad package. The package allows heat to be

conducted from the die down through the exposed metal pad

underneath the package and into the copper of the pcb. In

order to best take advantage of this feature, a grid array of

thru-hole vias should be placed in the area corresponding to

the exposed pad, and these vias then should then connect to

a large ground plane of copper to dissipate the heat into the

ambient environment. An example of these vias can be seen

in the previous figures of a typical pcb layout.