BQ24070 Datasheet, PDF (22/26 Pages) Texas Instruments – SINGLE-CHIP CHARGE AND SYSTEM POWER-PATH MANAGEMENT IC

bq24070
SLUS694A – MARCH 2006 – REVISED MARCH 2006
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APPLICATION INFORMATION (continued)
PCB Layout Considerations
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).
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