www.ti.com

PCB Layout Considerations

bq24070

SLUS694A – MARCH 2006 – REVISED MARCH 2006

APPLICATION INFORMATION (continued)

It is important to pay special attention to the PCB layout. The following provides some guidelines:

•

To obtain optimal performance, the decoupling capacitor from the input terminal to VSS and the output filter

capacitor from OUT to VSS should be placed as close as possible to the bq24070, with short trace runs to

both signal and VSS pins.

•

All low-current VSS connections should be kept separate from the high-current charge or discharge paths

from the battery. Use a single-point ground technique incorporating both the small signal ground path and

the power ground path.

•

The high-current charge paths into IN and from the BAT and OUT pins must be sized appropriately for the

maximum charge current in order to avoid voltage drops in these traces.

•

The bq24070 is packaged in a thermally enhanced MLP package. The package includes a QFN thermal pad

to provide an effective thermal contact between the device and the printed-circuit board. Full PCB design

guidelines for this package are provided in the application note entitled QFN/SON PCB Attachment

(SLUA271).

22

Submit Documentation Feedback