STBC21 Datasheet, PDF (49/54 Pages) STMicroelectronics – LI+ battery charger with thermal regulation

STBC21
Charger, battery and alarm status registers
Table 46. Battery temperature range
000
001
010
011
100
101
110
111
No battery
Battery temperature > 60 ºC
Battery temperature > 50 ºC
Battery temperature > 45 ºC
Battery temperature > 10 ºC
Battery temperature > 0 ºC
Battery temperature < 0 ºC
Battery temperature < 0 ºC
H.1
Layout guidelines
The layout of the application board for the STBC21 is very critical due to the high precision
required on charging parameters which can be met only by minimizing the voltage drops
across the connecting tracks and the noise in the ground plane.
For these reasons the following guidelines are strongly suggested:
1. Input and output decoupling capacitor should be placed as close as possible to the
STBC21 with short trace runs to both IN, OUT.
2. All low current GND connections should be kept separate from the high current charge
or discharge paths from the battery.
3. Use a single-point ground technique incorporating both the small signal ground path
and the power ground path.
4. The high current charge paths into the IN pin and from the OUT pin must be sized
appropriately in order to avoid voltage drops in these traces.
5. VBAT_SNS must be connected to VBAT as near as possible to the battery pin.
The layout of the board is reported below.
Figure 17. Layout board (top through view)
Doc ID 023256 Rev 1
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