AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
1
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
General Description
The AAT3683 BatteryManager is a highly integrated sin-
gle-cell lithium-ion / polymer (Li-Ion) battery charger
that operates from a USB port or an AC adapter input up
to an input voltage of 7.5V.
The AAT3683 precisely regulates battery charge voltage
and current for 4.2V Li-Ion battery cells. The battery
charging current can be set by an external resistor up to
1A.
Digital Thermal Loop Control maintains the maximum
possible battery charging current for the given set of
input to output power dissipation and ambient tempera-
ture conditions.
Battery charge state is continuously monitored for fault
conditions. In the event of an over-current, over-voltage,
short-circuit, or over-temperature condition, the device
will shut down automatically, thus protecting the charg-
ing device, control system, and the battery under
charge. A status monitor output pin is provided to indi-
cate the battery charge status by directly driving an
external LED. An open-drain power source detection out-
put is provided to report the power supply status.
The AAT3683 is available in the Pb-free, thermally-
enhanced, space-saving 2.2 x 2.2mm 10-pin STDFN
(AAT3683-2) and 16-pin QFN33 (AAT3683-4) packages
and is specified for operation over the -40°C to +85°C
temperature range.
Features
• USB or AC Adapter Input
• Programmable from 100mA to 1A
• 4.0V to 7.5V Input Voltage Range
• High Level of Integration with Internal:
Charging Device
Reverse Blocking Diode
Current Sensing
• Digital Thermal Regulation
• Charge Current Programming (ISET)
• Charge Termination Current Programming (TERM)
• Charge Timer (CT)
• Battery Temperature Sensing (TS)
• TS Pin Open Detection
• Automatic Recharge Sequencing
• Automatic Trickle Charge for Battery Pre-Conditioning
(no trickle charge option available)
• Full Battery Charge Auto Turn-Off / Sleep Mode /
Charge Termination
• 1A Max. Shutdown Current
• Over-Voltage and Over-Current Protection
• Emergency Thermal Protection
• Power On Reset and Soft Start
• 2.2 x 2.2mm STDFN-10 (AAT3863-2) and QFN33-16
(AAT3683-4) Packages
Applications
• Bluetooth Headsets, Headphones, Accessories
• Cellular Phones
• Digital Still Cameras
• MP3, Portable Music, and Portable Media Players
• Personal Data Assistants (PDAs) and Handheld
Computers
• Other Li-Ion Battery-Powered Devices
Typical Application
VIN
RTERM
ADPP#
ENABLE
EN
TERM
GND
BAT
STAT
RSET
ISET
IN
AAT3683-2
BATT-
TEMP
Battery
Pack
BATT+
BATT
TEMP
Battery
Pack
BATT+
TS
CBAT
CIN
CT
CT
RTERM
STAT2
EN
TERM
BAT
STAT1
IN
AAT3683-4
BATT-
TEMP
Battery
Pack
BATT+
BATT-
TEMP
Battery
Pack
BATT+
TS
CBAT
RT
VIN
ENABLE
CIN
GND RSET
ISET
CT
CT
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
2Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Pin Descriptions
Pin
Name Type Function
AAT3683-2 AAT3683-4
1 n/a STAT OCharge status pin, open drain.
n/a 16 STAT1 Charge status pin, open drain.
2 2 TERM
I
Charge termination current programming input pin (internal default 10%
termination current if TERM is open).
3 3 GND Ground.
4 4 CT Charge timer programming input pin (no timer if grounded).
5 n/a ADPP# OInput supply power-good status pin, open drain.
n/a 5 STAT2 Charge status pin, open drain.
6 7 TS I/O Battery temperature sense pin. (Leave this TS pin open to disable this
function in AAT3683-2).
7 6 BAT O Connect to Li-Ion battery.
815IN
I
Input from USB port/AC adapter connector.
9 11 ISET Charge current programming input pin.
10 12 EN Active high enable pin (with internal pull-down).
n/a 1, 8, 9, 10,
13, 14 N/C Not connected.
EP Exposed paddle (bottom); connect to ground as closely as possible to the
device.
Pin Configuration
AAT3683-2 AAT3683-4
STDFN2.2x2.2-10 QFN33-16
(Top View) (Top View)
GND
A
DPP#
CT
STAT
TERM
IN
TS
BAT
EN
ISE
T
3
4
5
1
2
8
7
6
10
9
EN
ISE
T
N/C
STAT1
N/C
TERM
GND
1
2
3
4
BAT
STAT2
TS
16
15
14
13
5
6
7
8
12
11
10
9
N/C
N/C
N/C
N/C
IN
CT
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
3
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
AAT3683 Feature Options
Product Battery Temperature Sense Status Indicator Display
AAT3683-2 For Use With 10k NTC Thermistor 1 LED
AAT3683-4 For Use With Any Thermistor 2 LEDs
Absolute Maximum Ratings1
Symbol Description Value Units
VIN IN Continuous -0.3 to 8.0 V
VNBAT, STAT, ADPP#, EN, ISET, TS, STAT1, STAT2 -0.3 to VIN + 0.3
TJJunction Temperature Range -40 to 150
°CTLEAD Maximum Soldering Temperature (at Leads) 300
TAOperating Temperature Range -40 to 85
Thermal Information2
Symbol Description Value Units
JA Thermal Resistance STDFN2.2x2.2-10 50 °C/W
QFN33-16
PDMaximum Power Dissipation (TA = 25°C) STDFN2.2x2.2-10 2W
QFN33-16
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions
specified is not implied.
2. Mounted on an FR4 board.
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
4Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Electrical Characteristics
VIN = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.
Symbol Description Conditions Min Typ Max Units
Operation
VIN Input Voltage Range 4.0 7.5 V
VUVLO
Under-Voltage Lockout Threshold Rising Edge 3 4
UVLO Hysteresis 150
mV
VADPP_TH
Adapter Present Indicator Threshold
Voltage, VIN - VBA VIN > VUVLO 60 110
IOP Operating Current Charge Current = 100mA 0.3 1mA
ISHUTDOWN Shutdown Current VBAT = 4.25V, EN = GND 0.4 A
ILEAKAGE Leakage Current from BAT Pin VBAT = 4V, IN Pin Open 2
Voltage Regulation
VBAT_EOC End of Charge Accuracy 4.158 4.20 4.242 V
VBAT_EOC/
VBAT_EOC
End of Charge Tolerance 0.5 %
VMIN Preconditioning Voltage Threshold (Option available for no trickle charge) 2.5 2.6 2.7
V
VRCH Battery Recharge Voltage Threshold VBAT_EOC
- 0.1
Current Regulation
ICC_RANGE Charge Current Programmable Range 100 1000 mA
ICH_CC Constant Current Mode Charge Current VIN = 6.5V and VBAT = 3.6V -12.5 12.5 %
VISET ISET Pin Voltage 2V
KISET Charge Current Set Factor: ICH_CC/IISET Constant Current Mode, VBAT = 3.6V 800
VTERM TERM Pin Voltage RTERM = 13.3K0.2 V
ICH_TRK Trickle-Charge Current 5 10 15 % ICH_CC
TERM Pin Open
ICH_TERM Charge Termination Threshold Current RTERM = 13.3K, ICH_CC 800mA 8 12 %
Charging Devices
RDS(ON) Charging Transistor On Resistance VIN = 5V 0.5 0.7
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
5
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Electrical Characteristics
VIN = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.
Symbol Description Conditions Min Typ Max Units
Logic Control / Protection
VEN(H) Input High Threshold 1.6
VVEN(L) Input Low Threshold 0.4
VSTAT Output Low Voltage STAT Pin Sinks 4mA 0.2
ISTAT STAT Pin Current Sink Capability 8mA
VADDP# Output Low Voltage ADPP# Pin Sinks 4mA 0.2 V
IADPP# ADDP# Pin Current Sink Capability 8mA
VOVP Over-Voltage Protection Threshold 4.4 V
IOCP Over-Current Protection Threshold 105 %ICH_CC
TK Trickle Timeout
CT = 0.1F, V IN = 5V
25 Minute
TC Trickle and Constant Current Mode Timeout 3 Hour
TV Constant Voltage Mode Timeout
ITS Current Source from TS Pin AAT3683-2 Only 69 75 81 A
TS1 TS Hot Temperature Fault Threshold, AAT3683-2 Only 316 331 346 mV
Hysteresis, AAT3683-2 Only 25
TS2 TS Cold Temperature Fault Threshold, AAT3683-2 Only 2.30 2.39 2.48 V
Hysteresis, AAT3683-2 Only 25 mV
VTS1 High Temperature Threshold AAT3683-4 Only 29.1 30 30.9 %VIN
VTS2 Low Temperature Threshold 58.2 60 61.8
TLOOP_IN Thermal Loop Entering Threshold 115
ºC
TLOOP_OUT Thermal Loop Exiting Threshold 85
TREG Thermal Loop Regulation 100
TSHDN Over-Temperature Shutdown Threshold 140
Hysteresis 15
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
6Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Typical Characteristics
Constant Charging Current
vs. Set Resistor Values
RSET (kΩ
Ω
)
CC Mode Charge Current (mA)
10
100
1000
10000
11010
0
Charging Current vs. Battery Voltage
VBAT (V)
ICH (mA)
0
200
400
600
800
1000
1200
2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.
3
RSET = 1.58k
RSET = 2k
RSET = 3.24k
RSET = 8.06k
End of Charge Regulation Accuracy
vs. Input Voltage
(VBAT_EOC = 4.2V)
Input Voltage (V)
Δ
Δ
VBAT_EOC/VBAT_EOC (%)
-0.20
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
4.5 5.0 5.5 6.0 6.5 7.0 7.5
End of Charge Voltage vs. Temperature
Temperature (°
°
C)
VEOC (V)
4.180
4.190
4.200
4.210
4.220
-50 -25 0 25 50 75 10
0
Preconditioning Charge Current
vs. Input Voltage
Input Voltage (V)
ICH_TRK (mA)
0
20
40
60
80
100
120
4 4.5 5 5.5 6 6.5 7 7.5
RSET = 1.58k
RSET = 2k
RSET = 3.24k
RSET = 8.06k
Preconditioning Voltage Threshold
vs. Temperature
Temperature (°
°
C)
VMIN (V)
2.4
2.45
2.5
2.55
2.6
2.65
2.7
-40 -15 10 35 60 85
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
7
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Typical Characteristics
Preconditioning Charge Current vs. Temperature
(RSET = 8.06k; ICH_CC = 200mA)
Temperature (°
°
C)
Preconditioning
Charge Current (mA)
17
18
19
20
21
22
23
-40 -15 10 35 60 85
Battery Recharge Voltage
Threshold vs. Temperature
Temperature (°
°
C)
VRCH (V)
4.04
4.06
4.08
4.10
4.12
4.14
-40 -15 10 35 60 8
5
Constant Charging Current vs. Input Voltage
(RSET = 1.58KΩ
Ω
)
Input Voltage (V)
Constant Charging Current
(mA)
700
750
800
850
900
950
1000
1050
1100
4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5
VBAT = 3.3V
VBAT = 3.5V
VBAT = 3.9V
Temperature Sense Output Current
vs. Temperature (AAT3683-2 Only)
Temperature (°
°
C)
ITS (µA)
68.0
70.0
72.0
74.0
76.0
78.0
-40 -15 10 35 60 85
Temperature Sense Too Hot Threshold
vs. Temperature (AAT3683-2 Only)
Temperature (°
°
C)
Temperature Sense
Threshold Voltage - TS1 (V)
0.320
0.325
0.330
0.335
0.340
0.345
-40 -15 10 35 60 8
5
Temperature Sense Too Cold Threshold
vs. Temperature (AAT3683-2 Only)
Temperature (°
°
C)
Temperature Sense
Threshold Voltage- TS2 (V)
2.37
2.38
2.39
2.40
2.41
2.42
-40 -15 10 35 60 85
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
8Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Typical Characteristics
Operating Current vs. ISET Resistor
RSET (kΩ
)
IOP (mA)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1 10 100 1000
Preconditioning Mode
Constant Current Mode
Shutdown Current vs. Input Voltage
Input Voltage (V)
ISHUTDOWN (µA)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
4 4.5 5 5.5 6 6.5 7 7.5
85°C
25°C
-40°C
Counter Timeout vs. Temperature
(CT = 0.1µF)
Temperature (°
°
C)
Counter Timeout (%)
-0.10
-0.05
0.00
0.05
0.10
-40 -15 10 35 60 85
CT Pin Capacitance vs. Counter Timeout
Time (hours)
Capacitance (µF)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
01 2 3 45
Preconditioning Timeout
Preconditioning + Constant Current
Timeout or Constant Voltage Timeout
Termination Current to Constant Current Ratio (%
)
vs. Termination Resistance
ITERM Resistance (kΩ
Ω
)
ICH_TERM/ICH_CC (%)
0%
10%
20%
30%
40%
50%
0 102030405060
Charging Transistor On Resistance
vs. Supply Voltage
VIN (V)
RDS(ON) (mΩ
Ω
)
400
450
500
550
600
650
700
750
800
3.6 3.9 4.2 4.5 4.8 5.1
85°C
25°C
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
9
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Typical Characteristics
Input High Threshold vs. Input Voltage
Input Voltage (V)
VEN(H) (V)
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.
5
85°C
25°C
-40°C
Input Low Threshold vs. Input Voltage
Input Voltage (V)
VEN(L) (V)
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.
5
85°C
25°C
-40°C
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
10 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Functional Description
The AAT3683 is a high performance battery charger
designed to charge single-cell lithium-ion or lithium-
polymer batteries with up to 1A of current from an exter-
nal power source. It is a stand-alone charging solution,
with just one external component required for complete
functionality.
The AAT3683 precisely regulates battery charge voltage
and current for 4.2V lithium-ion/polymer battery cells
with constant current level being programmed up to 1A
for rapid charging applications. The charge termination
current can be programmed by an external resistor.
The AAT3683 is rated for operation from -40°C to
+85°C. In the event of operating ambient temperatures
exceeding the power dissipation abilities of the device
package for a given constant current charge level, the
charge control will enter into thermal limit.
AAT3683-2 provides one status monitor output pin
(STAT) by directly driving one external LED to indicate
the battery charging state. AAT3683-4 provides two sta-
tus pins to indicate the battery charging state.
Device junction temperature and charge state are fully
monitored for fault conditions. In the event of an over-
voltage or over-temperature failure, the device will auto-
matically shut down, protecting the charging device,
control system, and the battery under charge.
During battery charging, the device temperature will
rise. In some cases with adapter (ADP) charging, the
power dissipation in the device may causethe junction
temperature to rise to close to its thermal shutdown
threshold. In the event of an internal over-temperature
condition caused by excessive ambient operating tem-
perature or excessive power dissipation condition, the
AAT3683 enables a digitally controlled thermal loop sys-
tem that will reduce the charging current to prevent the
device from thermal shutdown. The digital thermal loop
will maintain the maximum possible battery charging
current for the given set of input to output power dissi-
pation and ambient temperature conditions.
Functional Block Diagram
Charge
Control
Current
Compare
Reverse Blocking
CV/ Pre-
charge
Constant
Current
IN BAT
ISET UVLO
Over-
Temp.
Protect
Power
Detection
STAT (3683-2 only)
GND
EN
Thermal
Loop
ADPP#
Charge
Status
Battery OV
Protection
STAT1 (3683-4 only)
STAT2 (3683-4 only)
(3683-2 only)
IC Enable Watchdog
Timer
CT
75μA
TS
(3683-2 only)
Window
Comparator
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
11
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
The digital thermal loop control is dynamic in the sense
that it will continue to adjust the battery charging cur-
rent as operating conditions change.
The digital thermal loop will reset and resume normal
operation when the power dissipation or over-tempera-
ture conditions are removed.
Battery Charging Operation
Figure 1 illustrates the entire battery charging profile or
operation, which consists of three phases:
1. Preconditioning (Trickle) Charge
2. Constant Current Charge
3. Constant Voltage Charge
Battery Preconditioning
Battery charging commences only after the AAT3683
checks several conditions in order to maintain a safe
charging environment. The input supply must be above
the minimum operating voltage (VUVLO) and the enable
pin must be high. When the battery is connected to the
BAT pin, the AAT3683 checks the condition of the bat-
tery and determines which charging mode to apply. If
the battery voltage is below the preconditioning voltage
threshold, VMIN, then the AAT3683 begins precondition-
ing the battery cell (trickle charging) by charging at
10% of the programmed constant current. For example,
if the programmed current is 500mA, then the precon-
ditioning mode (trickle charge) current is 50mA. Battery
cell preconditioning (trickle charging) is a safety precau-
tion for deeply discharged cells and will also reduce the
power dissipation in the internal series pass MOSFET
when the input-output voltage differential is at the
greatest potential.
Constant Current Charging
Battery cell preconditioning continues until the battery
voltage reaches the preconditioning voltage threshold,
VMIN. At this point, the AAT3683 begins constant current
charging. The current level for this mode is programmed
using a single resistor from the ISET pin to ground.
Programmed current can be set at a minimum 100mA up
to a maximum of 1A.
Constant Voltage Charging
Constant current charging will continue until such time
that the battery voltage reaches the voltage regulation
point, VBAT_EOC. When the battery voltage reaches VBAT_EOC,
the AAT3683 will transition to constant voltage mode.
The regulation voltage is factory programmed to a nom-
inal 4.2V and will continue charging until the charge
termination current is reached.
Constant Current
Charge Phase
Constant Voltage
Charge Phase
Preconditioning
Trickle Charge
Phase
Charge Complete Voltage
Constant Current Mode
Voltage Threshold
Regulated Current
Trickle Charge and
Termination Threshold
I = CC / 10
I = Max CC
Figure 1: Current vs. Voltage Profile During Charging Phases.
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
12 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
System Operation Flow Chart
Power On Reset
Power Input
Voltage
V
IN
> V
UVLO
Fault
Conditions Monitoring
OV, OT,
TS>V
TS2
or TS<V
TS1
Preconditioning
Test
V
MIN
> V
BAT
Current Phase Test
V
IN
> V
BAT_EOC
Voltage Phase Test
I
BAT
> I
TERM
No
No
Yes
No
Preconditioning
(Trickle Charge)
Constant
Current Charge
Mode
Constant
Voltage Charge
Mode
Yes
Yes
Yes
Charge Completed
Charge Timer
Control
No
Recharge Test
V
RCH
> V
BAT
Yes
No
Shut Down Yes
Enable
Yes
No
Device Thermal
Loop Monitor
T
J
> 115°C
Thermal Loop
Current
Reduction in ADP
Charging Mode
Thermal Loop
Current
Reduction in
C.C. Mode
No
Enable
Expired
Yes
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
13
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Application Information
Adapter or USB Power Input
Constant current charge levels up to 1A may be pro-
grammed by the user when powered from a sufficient
input power source. The AAT3683 will operate from the
adapter input over a 4.0V to 7.5V range. The constant
current mode fast charge current for the adapter input
is set by the RSET resistor connected between ISET and
ground. Refer to Table 4 for recommended RSET values
for a desired constant current charge level.
Adapter Input Charge Inhibit and Resume
The AAT3683 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 IN 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.
Digital Thermal Loop Control
Due to the integrated nature of the linear charging con-
trol pass device for the adapter mode, a special thermal
loop control system has been employed to maximize
charging current under all operation conditions. The
thermal management system measures the internal cir-
cuit die temperature and reduces the fast charge current
when the device exceeds a preset internal temperature
control threshold. Once the thermal loop control becomes
active, the fast charge current is initially reduced by a
factor of 0.44.
The initial thermal loop current can be estimated by the
following equation:
ITLOOP = ICH_CC · 0.44
The thermal loop control re-evaluates the circuit die tem-
perature every three seconds and adjusts the fast charge
current back up in small steps to the full fast charge cur-
rent level or until an equilibrium current is discovered
and maximized for the given ambient temperature condi-
tion. The thermal loop controls the system charge level;
therefore, the AAT3683 will always provide the highest
level of constant current in the fast charge mode possible
for any given ambient temperature condition.
Enable / Disable
The AAT3683 provides an enable function to control the
charger IC on and off. The enable (EN) pin is internally
pulled down. When pulled to a logic high level, AAT3683
is enabled. When left open or pulled to a logic low level,
the AAT3683 will be shut down. 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.
Programming Charge Current
The constant current mode charge level is user pro-
grammed with a set resistor placed between the ISET pin
and ground. The accuracy of the constant charge cur-
rent, as well as the preconditioning trickle charge cur-
rent, is dominated by the tolerance of the set resistor
used. For this reason, a 1% tolerance metal film resistor
is recommended for the set resistor function. The con-
stant charge current levels from 100mA to 1A may be set
by selecting the appropriate resistor value from Table 1.
Constant Charging
Current (mA)
Set Resistor
Value (k)
100 16.2
200 8.06
300 5.36
400 4.02
500 3.24
600 2.67
700 2.26
800 2
900 1.78
1000 1.58
Table 1: RSET Values.
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
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RSET (kΩ
Ω
)
ICH_CC (mA)
10
100
1000
10000
11010
0
Figure 2: Constant Charging Current
vs. Set Resistor Values.
Programmable Charge
Termination Current
The charge termination current ICH_TERM can be pro-
grammed by connecting a resistor from TERM to GND:
ICH_TERM = · ICH_CC
15µA · RTERM
2V
If the TERM pin is left open, the termination current will
set to 10% of the constant charging current as the
default value.
When the charge current drops to the defaulted 10% of
the programmed charge current level or programmed
terminated current in the constant voltage mode, the
device terminates charging and goes into a sleep state.
The charger will remain in this sleep state until the bat-
tery voltage decreases to a level below the battery
recharge voltage threshold (VRCH).
Consuming very low current in sleep state, the AAT3683
minimizes battery drain when it is not charging. This
feature is particularly useful in applications where the
input supply level may fall below the battery charge or
under-voltage lockout level. In such cases where the
AAT3683 input voltage drops, the device will enter sleep
state and automatically resume charging once the input
supply has recovered from the fault condition.
Charge Status Output
The AAT3683 provides battery charge status via a status
pin (AAT3683-4 provides battery charge status via two
status pins). This pin is internally connected to an
N-channel open-drain MOSFET, which can be used drive
an external LED. The status pin can indicate the follow-
ing conditions (AAT3683-2):
Event Description STATUS
No battery charging activity OFF
Battery charging via adapter or USB port ON
Charging completed OFF
Table 2: LED Status Indicator
(AAT3683-2).
The status pins can indicate the following conditions
(AAT3683-4):
Event Description STAT1 STAT2
Charge enabled without battery FLASH1FLASH1
Battery charging ON OFF
Charge completed OFF ON
Fault OFF
Table 3: LEDs Status Indicator
(AAT3683-4).
The LED should be biased with as little current as neces-
sary to create reasonable illumination; therefore, a bal-
last resistor should be placed between the LED cathode
and the STAT pin. LED current consumption will add to
the overall thermal power budget for the device pack-
age, hence it is good to keep the LED drive current to a
minimum. 2mA should be sufficient to drive most low-
cost green or red LEDs. It is not recommended to exceed
8mA for driving an individual status LED.
1. Flashing rate depends on output capacitance.
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
15
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The required ballast resistor values can be estimated
using the following formula:
V
IN -
V
F(LED)
R
BALLAST
= I
LED
Example:
5.0V
- 2.0
V
R
BALLAST
= = 1.5kΩ
2mA
Note: Red LED forward voltage VF is typically 2.0V @
2mA.
Protection Circuitry
Programmable Watchdog Timer
The AAT3683 contains a watchdog timing circuit to shut
down charging functions in the event of a defective bat-
tery cell not accepting a charge over a preset period of
time. Typically, a 0.1F ceramic capacitor is connected
between the CT pin and ground. When a 0.1F ceramic
capacitor is used, the device will time out a shutdown
condition if the trickle charge mode exceeds 25 minutes
and a combined trickle charge plus constant current
mode of 3 hours. When the device transitions to the
constant voltage mode, the timing counter is reset and
will time out after an additional 3 hours if the charge
current does not drop to the charge termination level.
The 3683-4 has a battery fault detector, which, when
used in conjunction with a 0.1F capacitor on the CT pin,
outputs a 1Hz signal with 50% duty cycle at the STAT1
pin in the event of a timeout while in the trickle charge
mode.
Mode Time
Trickle Charge (TC) Time Out 25 minutes
Trickle Charge (TC) + Constant Current
(CC) Mode Time Out 3 hours
Constant Voltage (VC) Mode Time Out
Table 4: Summary for a 0.1μF Ceramic Capacitor
Used for the Timing Capacitor.
The CT pin is driven by a constant current source and
will provide a linear response to increases in the timing
capacitor value. Thus, if the timing capacitor were to be
doubled from the nominal 0.1F value, the time-out
periods would be doubled.
If the programmable watchdog timer function is not
needed, it can be disabled by terminating the CT pin to
ground. The CT pin should not be left floating or un-
terminated, as this will cause errors in the internal tim-
ing control circuit.
The constant current provided to charge the timing
capacitor is very small, and this pin is susceptible to
noise and changes in capacitance value. Therefore, the
timing capacitor should be physically located on the
printed circuit board layout as close as possible to the CT
pin. Since the accuracy of the internal timer is domi-
nated by the capacitance value, a 10% tolerance or bet-
ter ceramic capacitor is recommended. Ceramic capaci-
tor materials, such as X7R and X5R types, are a good
choice for this application.
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 (VOVP). If an over-voltage condition
occurs, the AAT3683 charge control will shut down the
device until the voltage on the BAT pin drops below VOVP
.
The AAT3683 will resume normal charging operation
after the over-voltage condition is removed. During an
over-voltage event, the STAT LEDs (3683-4 only) will
report a system fault.
Over-Temperature Shutdown
The AAT3683 has a thermal protection control circuit
which will shut down charging functions should the inter-
nal die temperature exceed the preset thermal limit
threshold. Once the internal die temperature falls below
the thermal limit, normal operation will resume the pre-
vious charging state.
Battery Temperature Fault Monitoring
In the event of a battery over-temperature condition,
the charge control will turn off the internal pass device
and report a battery temperature fault on the STAT pins.
After the system recovers from a temperature fault, the
device will resume charging operation.
The AAT3683-2 checks battery temperature before
starting the charge cycle, as well as during all stages of
charging. This is accomplished by monitoring the voltage
at the TS pin. This system is intended for use with
negative temperature coefficient thermistors (NTC)
which are typically integrated into the battery package.
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
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201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Most of the commonly used NTC thermistors in battery
packs are approximately 10k at room temperature
(25°C). The TS pin (3683-2 only) has been specifically
designed to source 75A of current to the thermistor.
The voltage on the TS pin resulting from the resistive
load should stay within a window of 331mV to 2.39V. If
the battery becomes too hot during charging due to an
internal fault or excessive constant charge current, the
thermistor will heat up and reduce in value, pulling the
TS pin voltage lower than the TS1 threshold, and the
AAT3683-2 will stop charging until the condition is
removed, when charging will be resumed.
If the use of the TS pin function is not required by the
system, it should be terminated to ground using a 10k
resistor. Alternatively, on the AAT3683-2 only, the TS pin
may be left open.
For AAT3683-4, the internal battery temperature sensing
system is comprised of two comparators which establish
a voltage window for safe operation. The thresholds for
the TS operating window are bounded by the TS1 and
TS2 specifications. Referring to the electrical characteris-
tics table in this datasheet, the TS1 threshold = 0.30 · VIN
and the TS2 threshold = 0.60 · VIN. If the use of the TS
pin function is not required on AAT3683-4, the TS pin
should be connected to input supply VIN.
0.60x V
IN
x V
IN
V
IN
Battery Cold Fault
Battery Hot Fault
IN
TS
AAT3683-4
Battery
Pack
Figure 3: AAT3683-4 Battery Temperature Sense
Circuit.
Thermal Considerations
The AAT3683 is offered in two packages (STDFN2.2x2.2-10
and QFN33-16) both of which can provide up to 2W of
power dissipation when properly bonded to a printed
circuit board and have a maximum thermal resistance of
50°C/W. Many considerations should be taken into
account when designing the printed circuit board layout,
as well as the placement of the charger IC package in
proximity to other heat generating devices in a given
application design. The ambient temperature around the
charger IC will also have an effect on the thermal limits
of a battery charging application. The maximum limits
that can be expected for a given ambient condition can
be estimated by the following discussion.
First, the maximum power dissipation for a given situa-
tion should be calculated:
T
J
- T
A
P
D(MAX)
= Θ
JA
Where:
PD(MAX) = Maximum Power Dissipation (W)
JA = Package Thermal Resistance (°C/W)
TJ = Thermal Loop Entering Threshold (ºC) [115ºC]
TA = Ambient Temperature (°C)
Figure 4 shows the relationship of maximum power dis-
sipation and ambient temperature of AAT3683.
TA (°
°
C)
PD(MAX) (W)
0
0.5
1
1.5
2
2.5
025507510
0
Figure 4: Maximum Power Dissipation Before
Entering Thermal Loop.
Next, the power dissipation can be calculated by the fol-
lowing equation:
PD = (VIN - VBAT) · ICH + VIN · IOP
Where:
PD = Total Power Dissipation by the Device
VIN = Input Voltage
VBAT = Battery Voltage as Seen at the BAT Pin
ICH = Constant Charge Current Programmed for the
Application
IOP = Quiescent Current Consumed by the Charger IC
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
17
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for Normal Operation [0.3mA]
By substitution, we can derive the maximum charge cur-
rent before reaching the thermal limit condition (thermal
loop). The maximum charge current is the key factor
when designing battery charger applications.
PD(MAX)
-
VIN
·
IOP
VIN - VBAT
ICH(MAX) =
TJ - TA
ΘJA
ICH(MAX) =
- VIN
·
IOP
VIN - VBAT
In general, the worst condition is the greatest voltage
drop across the charger IC, when battery voltage is
charged up to the preconditioning voltage threshold and
before entering thermal loop regulation. Figure 5 shows
the maximum charge current in different ambient tem-
peratures.
VIN (V)
ICC_MAX (mA)
0
200
400
600
800
1000
4.25 4.5 4.75 5 5.25 5.5 5.75 6 6.25 6.5 6.75 7
TA = 85°CTA = 60°C
TA = 45°C
TA = 25°C
Figure 5: Maximum Charging Current Before the
Digital Thermal Loop Becomes Active.
Capacitor Selection
Input Capacitor
In general, it is good design practice to place a decou-
pling capacitor between the IN pin and GND. An input
capacitor in the range of 1F to 22F is recommended.
If the source supply is unregulated, it may be necessary
to increase the capacitance to keep the input voltage
above the under-voltage lockout threshold during device
enable and when battery charging is initiated. If the
AAT3683 adapter input is to be used in a system with an
external power supply source, such as a typical AC-to-
DC wall adapter, then a CIN capacitor in the range of
10F should be used. A larger input capacitor in this
application will minimize switching or power transient
effects when the power supply is “hot plugged” in.
Output Capacitor
The AAT3683 only requires a 1F ceramic capacitor on
the BAT pin to maintain circuit stability. This value should
be increased to 10F or more if the battery connection
is made any distance from the charger output. If the
AAT3683 is to be used in applications where the battery
can be removed from the charger, such as with desktop
charging cradles, an output capacitor greater than 10F
may be required to prevent the device from cycling on
and off when no battery is present.
Printed Circuit Board
Layout Considerations
For the best results, it is recommended to physically
place the battery pack as close as possible to the
AAT3683 BAT pin. To minimize voltage drops on the PCB,
keep the high current carrying traces adequately wide.
When designing with >500mA charging current system,
a multilayer PCB design is highly recommended. Putting
thermal vias on the thermal pad design will effectively
transfer heat from the top metal layer of the PCB to the
inner or bottom layers. The number of thermal vias will
depend on the application and power dissipation. Refer
to the AAT3683 evaluation board for a good layout
example.
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
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Figure 6: AAT3683-2 Evaluation Board Figure 7: AAT3683-2 Evaluation Board
Top Side Layout. Middle Layer.
Figure 8: AAT3683-2 Evaluation Board
Bottom Side Layout.
R3 1.5k
C1
10μF
C2
10μF
VIN
R1
1.58k
Enable
JP1
VBAT
STDFN2.2x2.2-10
JP2
STAT
1
TERM
2
GND
3
CT
4
BAT
7
IN
8
ISET
9
EN
10
TS
6
ADPP#
5
U1 AAT3683-2 R5
10K
C3
0.1μF
D2
RED
LED
D1
GRN
LED
R4
1.5k R2
13.3k
Figure 9: AAT3683-2 Evaluation Board Schematic.
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
19
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201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Figure 10: AAT3683-4 Evaluation Board Figure 11: AAT3683-4 Evaluation Board
Top Side Layout. Middle Layer.
Figure 12: AAT3683-4 Evaluation Board Bottom Side Layout.
GRN LED
RED LED
D1
R3 1.5k
10μF
C2
VIN
R1
1.58k
Enable
JP1
VBAT
JP2
R5
10K
C3
0.1μF
D2
1.5k
R4
R2
13.3k
N/C
1
TERM
2
GND
3
CT
4
STAT2
5
BAT
6
TS
7
N/C
8
N/C
9
N/C
10
ISET
11
EN
12
N/C
13
N/C
14
IN
15
STAT1
16
AAT3683-4
QFN33-16
U1
R6
10K
Figure 13: AAT3683-4 Evaluation Board Schematic.
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
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201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Component Part Number Description Manufacturer
U1 AAT3683IOQ-4.2-2 1A Linear Li-Ion Battery Charger, 2.2x2.2mm STDFN-10 Package Skyworks
R1
Chip Resistor
1.58K, 1%, 1/4W 0603
Vishay
R2 13.3K, 1%, 1/4W 0603
R3, R4 1.5K, 5%, 1/4W 0402
R5 10K, 1%, 1/4W 0603
C1, C2 ECJ-1VB0J106M CER 10F 6.3V 10% X5R 0603 Panansonic
C3 GRM188R71C104KA01 CER 0.1F 6.3V 10% X7R 0603 Murata
JP1 PRPN401PAEN Conn. Header, 2mm zip Sullins Electronics
D1 CMD15-21VGC/TR8 Green LED 1206 Chicago Miniature Lamp
D2 CMD15-21SRC/TR8 Red LED 1206
Table 5: AAT3683-2 Evaluation Board Bill of Materials.
Component Part# Description Manufacturer
U1 AAT3683IVN-4.2-4 1A Linear Li-Ion Battery Charger, QFN33-16 Package Skyworks
R1
Chip Resistor
1.58K, 1%, 1/4W 0603
Vishay
R2 13.3K, 1%, 1/4W 0603
R3, R4 1.5K, 5%, 1/4W 0402
R5, R6 10K, 1%, 1/4W 0603
C1, C2 GRM21BR61A106KE19 CER 10F 10V 10% X5R 0805 Murata
C3 GRM188R71C104KA01 CER 0.1F 6.3V 10% X7R 0603
JP1 PRPN401PAEN Conn. Header, 2mm zip Sullins Electronics
D1 CMD15-21VGC/TR8 Green LED 1206 Chicago Miniature Lamp
D2 CMD15-21SRC/TR8 Red LED 1206
Table 6: AAT3683-4 Evaluation Board Bill of Materials.
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
21
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Ordering Information
Package Marking1Part Number (Tape and Reel)2
STDFN-10 (2.2x2.2mm) WIXYY AAT3683IOQ-4.2-2-T1
QFN33-16 WKXYY AAT3683IVN-4.2-4-T1
Skyworks Green™ products are compliant with
all applicable legislation and are halogen-free.
For additional information, refer to Skyworks
Definition of Green™, document number
SQ04-0074.
Package Information3
STDFN2.2x2.2-10
Top View Bottom View
2.200
±
0.050
1.710
±
0.050
2.200
±
0.050 1.000
±
0.050
Index Area
0.025
±
0.025
0.550
±
0.050
0.152 REF
Side View
Pin 1 Indicator
(optional)
R0.200
0.400 BSC0.210
±
0.050
0.350
±
0.050
Detail "A"
Detail "A"
All dimensions in millimeters.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
3. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing
process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection.
AAT3683
DATA SHEET
1A Linear Li-Ion Battery Charger
22 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
201885B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 25, 2012
Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved.
Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products or services. These materials, including the information contained herein, are provided by Skyworks as a
service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. Sky-
works may change its documentation, products, services, specifi cations or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no
responsibility whatsoever for confl icts, incompatibilities, or other diffi culties arising from any future changes.
No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided here-
under, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale.
THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR
PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES
NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. SKYWORKS SHALL NOT BE LIABLE FOR ANY DAMAGES, IN-
CLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM
THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, or other equipment in which the failure of the Skyworks products could lead to personal injury, death, physical or en-
vironmental damage. Skyworks customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper
use or sale.
Customers are responsible for their products and applications using Skyworks products, which may deviate from published specifi cations as a result of design defects, errors, or operation of products outside of pub-
lished parameters or design specifi cations. Customers should include design and operating safeguards to minimize these and other risks. Skyworks assumes no liability for applications assistance, customer product
design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifi cations or parameters.
Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for
identifi cation purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference.
QFN33-16
3.000
±
0.050
Pin 1 Dot By Marking
1.250
±
0.050
0.400
±
0.100
1.250
±
0.050
3.000
±
0.050
0.500
±
0.050
0.900
±
0.100
Pin 1 Identification
C0.3
0.025
±
0.025
0.214
±
0.036
0.230
±
0.050
Top View Bottom View
Side View
1
13
5
9
All dimensions in millimeters.