AAT3681AIJS-4.2-3-T1 AnalogicTech, AAT3681AIJS-4.2-3-T1 Datasheet - Page 12

• Manufacturer Part Number: AAT3681AIJS-4.2-3-T1
• Description: 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger: Trickle Charge: Yes; Enable: Active Low Active Low; Package: SC70JW-8
• Manufacturer: AnalogicTech

Application Information
Adapter or USB Power Input
Constant current charge levels up to 500mA may be
programmed by the user when powered from a sufficient
input power source. The AAT3681A will operate from the
adapter input over a 4.0V to 7.5V range. The constant
current fast charge current for the adapter input is set
by the R
Refer to Table 1 for recommended R
desired constant current charge level.
Adapter Input Charge Inhibit and Resume
The AAT3681A has a UVLO and power on reset feature
so that if the input supply to the ADP pin drops below the
UVLO threshold, the charger will suspend charging and
shut down. When power is re-applied to the ADP pin or
the UVLO condition recovers, the system charge control
will assess the state of charge on the battery cell and will
automatically resume charging in the appropriate mode
for the condition of the battery.
Enable / Disable
The AAT3681A provides an enable function to control the
charger IC on and off. The EN pin functions as follows on
the various AAT3681A options:
AAT3681A,
AAT3681A-5: The enable (EN) pin is internally pulled
down through a 6MΩ resistor. When pulled to a logic high
level, the AAT3681A is enabled. When left open or pulled
to a logic low level, the AAT3681A will be shut down and
forced into the sleep state.
AAT3681A-2: The enable (EN) pin is internally pulled
down. When left open or pulled to a logic low level, the
AAT3681A-2 is enabled. When pulled to a logic high
level, the AAT3681A-2 will be shut down and forced into
the sleep state.
Charging will be halted regardless of the battery voltage
or charging state. When the device is re-enabled, the
charge control circuit will automatically reset and resume
charging functions with the appropriate charging mode
based on the battery charge state and measured cell
voltage on the BAT pin.
12
BatteryManager
SET
resistor connected between ISET and ground.
AAT3681A-1,
TM
500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger
AAT3681A-4,
SET
values for a
w w w . a n a l o g i c t e c h . c o m
and
Programming Charge Current
The fast charge constant current charge level is user
programmed with a set resistor placed between the ISET
pin and ground. The accuracy of the fast charge, as well
as the preconditioning trickle charge current, is domi-
nated by the tolerance of the set resistor used. For this
reason, a 1% tolerance metal film resistor is recom-
mended for the set resistor function. Fast charge con-
stant current levels from 15mA to 500mA may be set by
selecting the appropriate resistor value from Table 1.
Protection Circuitry
Over-Voltage Protection
An over-voltage event is defined as a condition where
the voltage on the BAT pin exceeds the maximum bat-
tery charge voltage and is set by the over-voltage pro-
tection threshold (V
I
CHARGE
Figure 2: Constant Charging Current
Nominal
1000
100
10
1
500
450
400
350
300
250
200
150
100
50
40
30
20
15
1
(mA)
vs. Set Resistor Values.
Table 1: R
OVP
PRODUCT DATASHEET
). If an over-voltage condition
10
AAT3681A
R
SET
SET
(kΩ Ω )
Values.
Set Resistor
Value (kΩ)
100
3.24
3.57
4.12
4.64
5.36
6.49
8.06
10.7
16.2
31.6
38.3
53.6
78.7
3681A.2009.12.1.7
105
1000