BQ35100 Datasheet, PDF (18/26 Pages) Texas Instruments – Lithium Primary Battery Fuel Gauge

bq35100
SLUSCM6A – JUNE 2016 – REVISED JULY 2016
Typical Applications (continued)
8.2.4 Application Curves
15
10
5
0
-5
-10
-15
-20
2800
-40qC
-20qC
25qC
65qC
85qC
3000 3200 3400 3600 3800 4000 4200
Battery Voltage (mV)
Figure 14. V_(Err) Across VIN (0 mA)
4400
D001
25
20
15
10
5
0
-5
-10
-15
-20
-25
-3000
-40qC
-20qC
-2000
25qC
65qC
85qC
-1000
0
1000
Current (mA)
Figure 16. I_(Err)
2000
3000
D003
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200
160
120
80
40
0
-40
-80
-120
-160
-200
25.2
-40°C
-20°C
25°C
65°C
85°C
27 28.8 30.6 32.4 34.2 36 37.8
Battery Voltage (V)
Figure 15. V_(Err) Across VIN (0 mA) 9 s
39.6
D002
2
1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-40 -20
0
20
40
60
Temperature (qC)
Figure 17. T_(Err)
80 100
D004
9 Power Supply Recommendations
Power supply requirements for the bq35100 are simplified due to the presence of the internal LDO voltage
regulation. The REGIN pin accepts any voltage level between 2.7 V and 4.5 V, which is optimum for single-cell
Li-primary applications.
Decoupling the REGIN pin should be done with a 0.1-μF 10% ceramic X5R capacitor placed close to the device.
REGIN can be powered from an alternate power source, such as, for example, the boost converter output, as
long as it is not also connected to the BAT input. In this case, BAT should only remain connected to the top of
the cell.
10 Layout
10.1 Layout Guidelines
10.1.1 Introduction
Attention to layout is critical to the success of any battery management circuit board. The mixture of high-current
paths with an ultralow-current microcontroller creates the potential for design issues that are not always trivial to
solve. Some of the key areas of concern are described in the following sections, and can help to enable success.
18
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