BQ24050 Datasheet, PDF (29/37 Pages) Texas Instruments – 800mA Single Cell Li-Ion Battery Charger With Automatic Adaptor/USB Detection

bq24050
bq24052
bq24055
www.ti.com.................................................................................................................................... SLUS940A – SEPTEMBER 2009 – REVISED SEPTEMBER 2009
Layout Tips
To obtain optimal performance, the decoupling capacitor from IN to GND (thermal pad) and the output filter
capacitors from OUT to GND (thermal pad) should be placed as close as possible to the bq2405x, with short
trace runs to both IN, OUT and GND (thermal pad).
• All low-current GND 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 pin and from the OUT pin must be sized appropriately for the maximum
charge current in order to avoid voltage drops in these traces
• The bq2405x family is packaged in a thermally enhanced MLP package. The package includes a thermal pad
to provide an effective thermal contact between the IC and the printed circuit board (PCB); this thermal pad is
also the main ground connection for the device. Connect the thermal pad to the PCB ground connection. It is
best to use multiple 10-mill vias in the power pad of the IC and in close proximity to conduct the heat to the
bottom ground plane. The bottom ground place should avoid traces that “cut off” the thermal path. The thinner
the PCB the less temperature rise. The EVM PCB has a thickness of 0.031 inches and uses 2 oz. (2.8-mill
thick) copper on top and bottom, and is a good example of optimal thermal performance.
SPACER
REVISION HISTORY
Changes from Original (August 2009) to Revision A ..................................................................................................... Page
• Changed the status of the devices From: Product Preview To: Prodcution Data ................................................................ 1
Copyright © 2009, Texas Instruments Incorporated
Submit Documentation Feedback
29
Product Folder Link(s): bq24050 bq24052 bq24055