AAT3698 Datasheet, PDF (15/21 Pages) Skyworks Solutions Inc. – 1.6A Linear Li-Ion Battery Charger in a 3x3 TDFN Package

DATA SHEET
AAT3698
1.6A Linear Li-Ion Battery Charger in a 3x3 TDFN Package
Application Information
Constant Charge Current
The constant current charge level is user programmed
with a set resistor connected between the ISET pin and
ground. The tolerance of the set resistor determines the
accuracy of the constant charge current as well as the
preconditioning trickle charge current. For this reason, a
1% tolerance metal film resistor is recommended for the
set resistor function. The constant charge current level
from 100mA to 1.6A is set by selecting the appropriate
resistor value from Table 4.
The approximate charge current (I_{CH_CC_typ}) can be found
using the following formula:
10000
1000
100
10
1
0.1
1
10
100
R_SET (KΩ)
Figure 3: Constant Charging Current vs.
Set Resistor Values.
I_{CH_CC_TYP} =
V_ISET
R_ISET
· K_ISET = V_ISET · GM_OUT
Where:
GM_OUT =
I_{CH_CC_TYP}
V_ISET
=
K_ISET
R_SET
=
250ms
When R_SET = 3.16kΩ and K_ISET = 790.
Typical Constant Charge
Current (mA)
50
100
200
400
500
600
800
1000
1580
Set Resistor Value
(kΩ)
31.6
15.8
7.87
3.92
3.16
2.67
1.96
1.58
1.00
Table 4: R_SET Values
Figure 3 shows the relationship of constant charging cur-
rent and set resistor values for the AAT3698-1/-2.
Charge Termination Current
The charge termination current level is programmed by
an external resistor (R_TERM) connected between the TERM
pin and ground. Use the resistor values listed in Table 5
to set the desired charge termination current.
R_TERM (KΩ)
6.65
13.3
26.7
40.2
53.6
I_{CH_TERM} (%)
5%
10%
20%
30%
40%
Table 5: Charge Termination Current
Programming Resistor Values.
50%
40%
30%
20%
10%
0%
0
10
20
30
40
50
60
R_TERM (kΩ)
Figure 4: Charge Termination Current vs. R_TERM.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
201902B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012
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