BQ24070_14 Datasheet, PDF (23/33 Pages) Texas Instruments – System Power-Path Management IC

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bq24070, bq24071
SLUS694G – MARCH 2006 – REVISED DECEMBER 2014
10 Power Supply Recommendations
A power supply capable of providing VCC between 4.35 V and 16 V and at least 100 mA up to 2 A is required for
the IC to operate. For the battery to fully charge, the power supply must be capable of providing at least V_O(BAT-
REG) ^{+ V}(BATDO)^{. As the input voltage increases, the IC's power dissipation increases. The thermal protection loop}
of the IC, as explained in Temperature Regulation and Thermal Protection, reduces the input current current from
the maximum (2 A when MODE = H and either 100 mA or 500 mA per ISET2 if MODE = L) to prevent damage to
the IC.
11 Layout
11.1 Layout Guidelines
• For optimal performance, place the decoupling capacitor from the input terminal to VSS and the output filter
capacitor from OUT to VSS as close as possible to the bq2407x, with short trace runs to both signal and VSS
pins.
• Keep all low-current VSS connections separate from the high-current charge or discharge paths from the
battery. Use a single-point ground technique incorporating 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 to avoid voltage drops in these traces.
• The bq2407x is packaged in a thermally enhanced MLP package. The MLP package includes a QFN thermal
pad to provide an effective thermal contact between the device and the printed-circuit board (PCB). For
detailed PCB design guidelines for this package, see the QFN/SON PCB Attachment Application Note
(SLUA271).
The recommend layout is shown in Figure 11.
11.2 Layout Example
Figure 11. Recommended Layout
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