Analogic AAT3683IOQ-4.2-3-T1 1a linear li-ion battery charger Datasheet

AAT3683
1A Linear Li-Ion Battery Charger
General Description
Features
The AAT3683 BatteryManager is a highly integrated single-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 6.5V.
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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 temperature 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 charging device, control system, and the battery under charge. A status monitor output pin is provided to indicate the battery
charge status by directly driving an external LED.
An open-drain power source detection output is
provided to report the power supply status.
The AAT3683 is available in the Pb-free, thermallyenhanced, space-saving 2.2x2.2mm 10-pin STDFN
(AAT3683-2 and -3) and 16-pin QFN33 (AAT3683-4)
packages and is specified for operation over the
-40°C to +85°C temperature range.
USB or AC Adapter Input
Programmable from 100mA to 1A
4.0V to 6.5V 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 PreConditioning (no trickle charge option available)
Full Battery Charge Auto Turn-Off / Sleep
Mode / Charge Termination
1µA Max. Shutdown Current
Over-Voltage and Over-Current Protection
Emergency Thermal Protection
Power On Reset and Soft Start
2.2x2.2mm STDFN-10 (AAT3863-2 and -3)
and QFN33-16 (AAT3683-4) Packages
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Applications
•
•
•
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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
•
ENABLE
BatteryManager™
ENABLE
BATT+
EN
IN
VIN
C IN
CBAT
AAT3683-2
IN
BAT
C IN
CBAT
RT
BATTBATT
TERM
BATT+
EN
VIN
BAT
TERM
AAT3683-4
R TERM
R TERM
STAT1
STAT
TEMP
ADPP#
CT
CT
3683.2007.06.1.0
CT
ISET
GND
TEMP
TS
STAT2
TS
R SET
Battery
Pack
CT
BATT-
ISET
GND
R SET
Battery
Pack
1
AAT3683
1A Linear Li-Ion Battery Charger
Pin Descriptions
Pin
AAT3683-2,
AAT3683-3
AAT3683-4
Name
Type
1
n/a
STAT
O
Charge status pin, open drain.
n/a
16
STAT1
O
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
4
4
CT
I
Charge timer programming input pin (no timer if grounded).
5
n/a
ADPP#
O
Input supply power-good status pin, open drain.
n/a
5
STAT2
O
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.
8
15
IN
I
Input from USB port/AC adapter connector.
9
11
ISET
I
Charge current programming input pin.
10
12
EN
I
Active high enable pin (with internal pull-down).
n/a
1, 8, 9, 10,
13, 14
N/C
EP
EP
Function
Ground.
Not connected.
Exposed paddle (bottom); connect to ground as closely as possible
to the device.
Pin Configuration
AAT3683-2,
AAT3683-3
STDFN2.2x2.2-10
(Top View)
AAT3683-4
QFN33-16
(Top View)
N/C
N/C
IN
STAT1
8
3
8
4
7
5
6
EN
ISET
IN
BAT
TS
N/C
TERM
GND
CT
13
10
2
14
1
15
16
STAT
TERM
GND
CT
ADPP#
1
12
2
11
3
10
4
9
EN
ISET
N/C
N/C
8
7
6
5
N/C
TS
BAT
STAT2
2
3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
AAT3683 Feature Options
Product
AAT3683-2
AAT3683-3
AAT3683-4
Battery Temperature Sense
Status Indicator Display
For Use With 10kΩ NTC Thermistor
For Use With Any Thermistor
For Use With Any Thermistor
1 LED
1 LED
2 LEDs
Absolute Maximum Ratings1
Symbol
VIN
VN
TJ
TLEAD
Description
IN Continuous
BAT, STAT, ADPP#, EN, ISET, TS, STAT1, STAT2
Operating Junction Temperature Range
Maximum Soldering Temperature (at Leads)
Value
Units
-0.3 to 7.5
-0.3 to VIN + 0.3
-40 to 150
300
V
V
°C
°C
Value
Units
Thermal Information2
Symbol
Description
θJA
Thermal Resistance
PD
Maximum Power Dissipation (TA = 25°C)
STDFN2.2x2.2-10
QFN33-16
STDFN2.2x2.2-10
QFN33-16
50
50
2
2
°C/W
W
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. Only one Absolute Maximum Rating should be applied at any one time.
2. Mounted on an FR4 board.
3683.2007.06.1.0
3
AAT3683
1A Linear Li-Ion Battery Charger
Electrical Characteristics
VIN = 5V, TA = -25°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.
Symbol
Description
Operation
VIN
Input Voltage Range
Under-Voltage Lockout Threshold
VUVLO
UVLO Hysteresis
VADPP_TH Adapter Present Indicator Threshold
Voltage, VIN - VBAT
IOP
Operating Current
ISHUTDOWN Shutdown Current
IBAT
Leakage Current from BAT Pin
Voltage Regulation
VBAT_EOC End of Charge Accuracy
ΔVBAT_EOC/
End of Charge Tolerance
VBAT_EOC
VMIN
Preconditioning Voltage Threshold
VRCH
Battery Recharge Voltage Threshold
Current Regulation
ICC_RANGE Charge Current Programmable Range
ICH_CC
Constant Current Mode Charge Current
VISET
ISET Pin Voltage
KISET
4
Charge Current Set Factor: ICH_CC/IISET
VTERM
ICH_TRK
TERM Pin Voltage
Trickle-Charge Current
ICH_TERM
Charge Termination Threshold Current
Conditions
Min
Rising Edge
4.0
3
Typ
Max
Units
6.5
4
V
V
mV
150
VIN > VUVLO
60
110
mV
Charge Current = 100mA
VBAT = 4.25V, EN = GND
VBAT = 4V, IN Pin Open
0.3
0.4
0.4
1
1
2
mA
µA
µA
4.20
4.242
V
4.158
0.5
(Option available for no
trickle charge)
2.5
2.6
%
2.7
VBAT_EOC
- 0.1
VBAT = 3.6V
100
-12.5
V
1000
12.5
2
Constant Current Mode,
VBAT = 3.6V
RTERM = 13.3KΩ
TERM Pin Open
RTERM = 13.3KΩ,
ICH_CC ≥ 800mA
V
mA
%
V
800
5
5
0.2
10
10
15
15
V
% ICH_CC
% ICH_CC
8
10
12
%
3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
Electrical Characteristics
VIN = 5V, TA = -25°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C.
Symbol
Description
Charging Devices
RDS(ON)
Charging Transistor On Resistance
Logic Control / Protection
VEN(H)
Input High Threshold
VEN(L)
Input Low Threshold
VSTAT
Output Low Voltage
ISTAT
STAT Pin Current Sink Capability
VADDP#
Output Low Voltage
IADPP#
ADDP# Pin Current Sink Capability
VOVP
Over-Voltage Protection Threshold
IOCP
Over-Current Protection Threshold
TK
Trickle Timeout
Trickle and Constant Current Mode
TC
Timeout
TV
Constant Voltage Mode Timeout
ITS
Current Source from TS Pin
TS1
TS Hot Temperature Fault
TS2
TS Cold Temperature Fault
VTS1
VTS2
High Temperature Threshold
Low Temperature Threshold
Thermal Loop Entering Threshold
Thermal Loop Exiting Threshold
Thermal Loop Regulation
TLOOP_IN
TLOOP_OUT
TREG
TSHDN
3683.2007.06.1.0
Over-Temperature Shutdown
Conditions
Min
VIN = 5V
Typ
Max
Units
0.5
0.7
Ω
1.6
CT = 0.1µF, VIN = 5V
4.4
105
25
V
V
V
mA
V
mA
V
%ICH_CC
Minute
CT = 0.1µF, VIN = 5V
3
Hour
0.4
0.2
8
0.2
8
STAT Pin Sinks 4mA
ADPP# Pin Sinks 4mA
CT = 0.1µF, VIN = 5V
AAT3683-2 Only
Threshold, AAT3683-2 Only
Hysteresis, AAT3683-2 Only
Threshold, AAT3683-2 Only
Hysteresis, AAT3683-2 Only
AAT3683-3, AAT3683-4 Only
AAT3683-3, AAT3683-4 Only
Threshold
Hysteresis
69
316
2.30
29.1
58.2
3
75
331
25
2.39
25
30
60
115
85
100
140
15
81
346
2.48
30.9
61.8
Hour
µA
mV
V
mV
%VIN
%VIN
ºC
ºC
ºC
ºC
5
AAT3683
1A Linear Li-Ion Battery Charger
Typical Characteristics
Charging Current vs. Battery Voltage
1200
10000
RSET = 1.58k
1000
1000
ICH (mA)
CC Mode Charge Current (mA)
Constant Charging Current
vs. Set Resistor Values
100
RSET = 2k
800
600
RSET = 3.24k
400
RSET = 8.06k
200
0
2.5
10
1
10
100
2.7
2.9
3.1
3.3
RSET (kΩ
Ω)
4.1
4.3
4.220
0.10
0.08
4.210
0.05
VEOC (V)
ΔVBAT_EOC/VBAT_EOC (%)
3.9
End of Charge Voltage vs. Temperature
(VBAT_EOC = 4.2V)
0.03
0.00
-0.03
4.200
4.190
-0.05
-0.08
-0.10
4.5
4.75
5
5.25
5.5
5.75
6
6.25
4.180
-50
6.5
-25
0
25
50
75
100
Temperature (°°C)
Supply Voltage (V)
Preconditioning Charge Current
vs. Supply Voltage
Preconditioning Voltage Threshold
vs. Temperature
120
2.7
RSET = 1.58k
100
2.65
RSET = 2k
80
60
2.6
VMIN (V)
ICH_TRK (mA)
3.7
VBAT (V)
End of Charge Regulation Tolerance
vs. Supply Voltage
RSET = 3.24k
40
2.55
2.5
RSET = 8.06k
20
2.45
0
4
4.5
5
5.5
Output Current (mA)
6
3.5
6
6.5
2.4
-40
-15
10
35
60
85
Temperature (°°C)
3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
Typical Characteristics
Preconditioning Charge Current vs. Temperature
Battery Recharge Voltage
Threshold vs. Temperature
(RSET = 8.06k; ICH_CC = 200mA)
4.14
22
4.12
21
VRCH (V)
Preconditioning
Charge Current (mA)
23
20
19
4.08
4.06
18
17
-40
4.10
4.04
-15
10
35
60
-40
85
-15
Temperature (°°C)
35
60
85
Temperature (°°C)
Constant Charging Current vs. Supply Voltage
Temperature Sense Output Current
vs. Temperature (AAT3683-2 Only)
(RSET = 1.58KΩ
Ω)
78.0
1100
VBAT = 3.3V
76.0
1000
VBAT = 3.5V
900
800
700
4.0
ITS (µA)
Constant Charging Current (mA)
10
74.0
72.0
VBAT = 3.9V
70.0
4.5
5.0
5.5
6.0
6.5
68.0
-40
-15
0.345
0.340
0.335
0.330
0.325
10
35
Temperature (°°C)
3683.2007.06.1.0
60
85
Temperature Sense Too Cold Threshold
vs. Temperature (AAT3683-2 Only)
Temperature Sense
Threshold Voltage- TS2 (V)
Temperature Sense
Threshold Voltage - TS1 (V)
Temperature Sense Too Hot Threshold
vs. Temperature (AAT3683-2 Only)
-15
35
Temperature (°°C)
VIN (V)
0.320
-40
10
60
85
2.42
2.41
2.40
2.39
2.38
2.37
-40
-15
10
35
60
85
Temperature (°°C)
7
AAT3683
1A Linear Li-Ion Battery Charger
Typical Characteristics
Operating Current vs. ISET Resistor
1.6
1
1.4
0.9
0.8
ISHUTDOWN (µA)
Constant Current Mode
1.2
IOP (mA)
Shutdown Current vs. Supply Voltage
1.0
Preconditioning Mode
0.8
0.6
0.4
0.7
85°C
0.6
0.5
25°C
0.4
0.3
0.2
0.2
-40°C
0.1
0.0
0
1
10
100
1000
4
4.5
5
5.5
RSET (kΩ
Ω)
CT Pin Capacitance vs. Counter Timeout
1.0
0.10
0.9
Capacitance (µF)
Counter Timeout (%)
6.5
VIN (V)
Counter Timeout vs. Temperature
(CT = 0.1µF)
0.05
0.00
-0.05
0.8
0.7
Preconditioning Timeout
0.6
0.5
0.4
0.3
Preconditioning + Constant Current
Timeout or Constant Voltage Timeout
0.2
0.1
0.0
-0.10
-40
-15
10
35
60
0
85
1
Temperature (°°C)
2
3
4
5
Time (hours)
Termination Current to Constant Current Ratio (%)
vs. Termination Resistance
Charging Transistor On Resistance
vs. Supply Voltage
50%
800
750
85°C
40%
700
RDS(ON) (mΩ
Ω)
ICH_TERM/ICH_CC (%)
6
30%
20%
650
600
550
500
10%
25°C
450
0%
0
10
20
30
40
ITERM Resistance (kΩ
Ω)
8
50
60
400
3.6
3.9
4.2
4.5
4.8
5.1
VIN (V)
3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
Typical Characteristics
Input High Threshold vs. Supply Voltage
Input Low Threshold vs. Supply Voltage
1.1
1.1
1.0
1.0
0.9
VEN(L) (V)
VEN(H) (V)
-40°C
25°C
0.8
-40°C
0.9
25°C
0.8
85°C
0.7
85°C
0.7
0.6
0.6
4.0
4.5
5.0
5.5
Supply Voltage (V)
3683.2007.06.1.0
6.0
6.5
4.0
4.5
5.0
5.5
6.0
6.5
Supply Voltage (V)
9
AAT3683
1A Linear Li-Ion Battery Charger
Functional Block Diagram
Reverse Blocking
IN
BAT
Current
Compare
ADPP#
Charge
Control
Constant
Current
ISET
(3683-2/-3 only)
CV/ Precharge
OverTemp.
Protect
Power
Detection
Battery OV
Protection
Thermal
Loop
75μA
(3683-2 only)
Charge
Status
TS
IC Enable
Window
Comparator
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 external 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.
CT
STAT (3683-2/-3 only)
STAT1 (3683-4 only)
STAT2 (3683-4 only)
Watchdog
Timer
EN
10
UVLO
GND
AAT3683-2 and -3 provide one status monitor output pin (STAT) by directly driving one external LED
to indicate the battery charging state. AAT3683-4
provides two status 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 automatically 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 temperature or excessive power
dissipation condition, the AAT3683 enables a digi3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
battery voltage is below the preconditioning voltage
threshold, VMIN, then the AAT3683 begins preconditioning the battery cell (trickle charging) by charging at 10% of the programmed constant current.
For example, if the programmed current is 500mA,
then the preconditioning mode (trickle charge) current is 50mA. Battery cell preconditioning (trickle
charging) is a safety precaution 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.
tally controlled thermal loop system 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
dissipation and ambient temperature conditions.
The digital thermal loop control is dynamic in the
sense that it will continue to adjust the battery
charging current as operating conditions change.
The digital thermal loop will reset and resume normal operation when the power dissipation or overtemperature conditions are removed.
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.
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
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 nominal 4.2V and will
continue charging until the charge termination current is reached.
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 battery and
determines which charging mode to apply. If the
Preconditioning
Trickle Charge
Phase
Constant Current
Charge Phase
Constant Voltage
Charge Phase
Charge Complete Voltage
I = Max CC
Regulated Current
Constant Current Mode
Voltage Threshold
Trickle Charge and
Termination Threshold
I = CC / 10
Figure 1: Current vs. Voltage Profile During Charging Phases.
3683.2007.06.1.0
11
AAT3683
1A Linear Li-Ion Battery Charger
System Operation Flow Chart
Enable
No
Power On Reset
Yes
Power Input
Voltage
VIN > VUVLO
Enable
Yes
Shut Down
Yes
Fault
Conditions Monitoring
OV, OT,
VTS1 < TS < V TS2
Expired
Charge Timer
Control
No
Preconditioning
Test
VMIN > VBAT
Yes
Preconditioning
(Trickle Charge)
Thermal
Loop
Thermal
Loop
Current
Current
ReductionininADP
Reduction
C.C.
ModeMode
Charging
Yes
No
No
No
Recharge Test
VRCH > VBAT
Yes
Current Phase Test
VIN > VBAT_EOC
Yes
Constant
Current Charge
Mode
Yes
Constant
Voltage Charge
Mode
Device Thermal
Loop Monitor
TJ > 115°C
No
Voltage Phase Test
IBAT > ITERM
No
Charge Completed
12
3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
Application Information
Adapter or USB Power Input
Constant current charge levels up to 1A may be
programmed by the user when powered from a sufficient input power source. The AAT3683 will operate from the adapter input over a 4.0V to 6.5V
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 reapplied 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
control 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 circuit 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
temperature every three seconds and adjusts the
fast charge current back up in small steps to the full
fast charge current level or until an equilibrium current is discovered and maximized for the given
ambient temperature condition. The thermal loop
3683.2007.06.1.0
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
programmed with a set resistor placed between the
ISET pin and ground. The accuracy of the constant
charge current, as well as the preconditioning trickle charge current, 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 constant charge current levels from 100mA to 1A may be set by selecting the
appropriate resistor value from Table 1.
Constant Charging
Current (mA)
100
200
300
400
500
600
700
800
900
1000
Set Resistor
Value (kΩ)
16.2
8.06
5.36
4.02
3.24
2.67
2.26
2
1.78
1.58
Table 1: RSET Values.
13
AAT3683
1A Linear Li-Ion Battery Charger
Charge Status Output
ICH_CC (mA)
10000
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 following conditions
(AAT3683-2, AAT3683-3):
1000
100
10
1
10
100
RSET (kΩ
Ω)
Figure 2: Constant Charging Current
vs. Set Resistor Values.
Programmable Charge Termination
Current
The charge termination current ICH_TERM can be
programmed by connecting a resistor from TERM
to GND:
ICH_TERM =
15µA · RTERM
· ICH_CC
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 battery 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.
Event Description
No battery charging activity
Battery charging via adapter or
USB port
Charging completed
STATUS
OFF
ON
OFF
Table 2: LED Status Indicator
(AAT3683-2/AAT3683-3).
The status pins can indicate the following conditions
(AAT3683-4):
Event Description
STAT1 STAT2
Charge enabled without battery FLASH1 FLASH1
Battery charging
ON
OFF
Charge completed
OFF
ON
Fault
OFF
OFF
Table 3: LEDs Status Indicator.
(AAT3683-4).
The LED should be biased with as little current as
necessary to create reasonable illumination; therefore, a ballast 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 package, 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.
14
\3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
The required ballast resistor values can be estimated using the following formula:
RBALLAST =
(VIN - VF(LED))
ILED
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 timing control circuit.
Example:
RBALLAST =
(5.0V - 2.0V)
= 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 battery cell not accepting a charge over a preset
period of time. Typically, a 0.1µF ceramic capacitor
is connected between the CT pin and ground. When
a 0.1µF 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 0.1µF 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
Trickle Charge (TC) Time Out
Trickle Charge (TC) + Constant
Current (CC) Mode Time Out
Constant Voltage (VC)
Mode Time Out
Time
25 minutes
3 hours
3 hours
Table 4: Summary for a 0.1µF Ceramic
Capacitor Used for the Timing Capacitor.
3683.2007.06.1.0
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 0.1µF value,
the time-out periods would be doubled.
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 dominated by the capacitance value, a 10%
tolerance or better ceramic capacitor is recommended. Ceramic capacitor 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 battery charge voltage and is set by the overvoltage protection 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 overvoltage 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 internal die temperature exceed the preset thermal limit threshold. Once the internal die temperature falls below the thermal limit, normal operation
will resume the previous 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
DATA pin function. The STAT LEDs will also display a system fault. After the system recovers from
a temperature fault, the device will resume charging operation.
15
AAT3683
1A Linear Li-Ion Battery Charger
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. Most of the commonly used NTC
thermistors in battery packs are approximately 10kΩ
at room temperature (25°C). The TS pin (3683-2
only) has been specifically designed to source 75µA
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 10kΩ resistor. Alternatively, on the AAT3683-2,
the TS pin may be left open.
For AAT3683-3 and -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 characteristics table in this
datasheet, the TS1 threshold = 0.30 · VIN and the TS2
threshold = 0.60 · VIN.
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
situation should be calculated:
PD(MAX) =
(TJ - TA)
θJA
Where:
PD(MAX) = Maximum Power Dissipation (W)
θJA
= Package Thermal Resistance (°C/W)
TJ
= Thermal Loop Entering Threshold (ºC)
[115ºC]
TA
= Ambient Temperature (°C)
Figure 4 shows the relationship of maximum power
dissipation and ambient temperature of AAT3683.
VIN
IN
AAT3683-3 and -4
2.5
0.60x VIN
Battery Cold Fault
TS
Battery
Pack
Battery Hot Fault
PD(MAX) (W)
2
1.5
1
0.5
0
x V IN
0
25
50
75
100
TA (°°C)
Figure 3: AAT3683-3 and -4 Battery
Temperature Sense Circuit.
16
Figure 4: Maximum Power Dissipation Before
Entering Thermal Loop.
\3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
Next, the power dissipation can be calculated by
the following 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 for Normal Operation [0.3mA]
By substitution, we can derive the maximum
charge current 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) - V · I
IN
OP
θJA
ICH(MAX) =
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 temperatures.
1000
TA = 45°C
ICC_MAX (mA)
800
TA = 25°C
600
400
200
TA = 85°C
0
4.25
4.5
4.75
TA = 60°C
5
5.25
5.5
5.75
6
6.25
6.5
6.75
Capacitor Selection
Input Capacitor
In general, it is good design practice to place a
decoupling capacitor between the IN pin and GND.
An input capacitor in the range of 1µF to 22µF 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
10µF 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 1µF ceramic capacitor on the BAT pin to maintain circuit stability. This
value should be increased to 10µF 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 10µF 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.
VIN (V)
Figure 5: Maximum Charging Current Before
the Digital Thermal Loop Becomes Active.
3683.2007.06.1.0
17
AAT3683
1A Linear Li-Ion Battery Charger
Figure 6: AAT3683-2 Evaluation Board
Top Side Layout.
Figure 7: AAT3683-2 Evaluation Board
Middle Layer.
Figure 8: AAT3683-2 Evaluation Board
Bottom Side Layout.
VIN
JP2
D1
GRN
LED
D2
RED
LED
R4
1.5k
VBAT
Enable
STDFN2.2x2.2-10
R3 1.5k
1
2
3
4
5
R2
13.3k
C3
0.1μF
STAT
EN
TERM ISET
GND
IN
CT
BAT
ADPP# TS
U1 AAT3683-2
JP1
10
9
8
7
6
R5 R1
10K 1.58k
C2
10μF
C1
10μF
Figure 9: AAT3683-2 Evaluation Board Schematic.
18
3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
Figure 10: AAT3683-3 Evaluation Board
Top Side Layout.
Figure 11: AAT3683-3 Evaluation Board
Middle Layer.
Figure 12: AAT3683-3 Evaluation Board
Bottom Side Layout.
VIN
JP2
D1
GRN
LED
D2
RED
LED
R3 1.5k
R4
1.5k
R2
13.3k
Enable
STDFN2.2x2.2-10
1
2
3
4
5
STAT
TERM
GND
CT
ADPP#
U1
C3
0.1μF
EN
ISET
IN
BAT
TS
AAT3683-3
R5
10K
VBAT
JP1
10
9
8
7
6
R6 R1
10K 1.58k
C2
10μF
C1
10μF
Figure 13: AAT3683-3 Evaluation Board Schematic.
3683.2007.06.1.0
19
AAT3683
1A Linear Li-Ion Battery Charger
Figure 14: AAT3683-4 Evaluation Board
Top Side Layout.
Figure 15: AAT3683-4 Evaluation Board
Middle Layer.
Figure 16: AAT3683-4 Evaluation Board
Bottom Side Layout.
VIN
JP2
D1
JP1
R3 1.5k
N/C
TERM
GND
CT
STAT2
BAT
TS
N/C
R2
13.3k
1
2
3
4
STAT1
IN
N/C
N/C
AAT3683-4
U1 16 15 14 13 QFN33-16
GRN LED
C3
0.1μF
EN
ISET
N/C
N/C
12
11
10
9
Enable
R5
10K
R1
1.58k
5 6 7 8
D2
R6
10K
R4
VBAT
1.5k
RED LED
C2
10μF
Figure 17: AAT3683-4 Evaluation Board Schematic.
20
3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
Component
U1
R1
R2
R3, R4
R5
C1, C2
C3
JP1
D1
D2
Part#
Description
Manufacturer
AAT3683IOQ-4.2-2
1A Linear Li-Ion Battery Charger,
2.2x2.2mm STDFN-10 Package
1.58KΩ, 1%, 1/4W 0603
13.3KΩ, 1%, 1/4W 0603
1.5KΩ, 5%, 1/4W 0402
10KΩ, 1%, 1/4W 0603
CER 10μF 6.3V 10% X5R 0603
CER 0.1μF 6.3V 10% X7R 0603
Conn. Header, 2mm zip
Green LED 1206
Red LED 1206
AnalogicTech
Chip Resistor
Chip Resistor
Chip Resistor
Chip Resistor
ECJ-1VB0J106M
GRM188R71C104KA01
PRPN401PAEN
CMD15-21VGC/TR8
CMD15-21SRC/TR8
Vishay
Vishay
Vishay
Vishay
Panansonic
Murata
Sullins Electronics
Chicago Miniature Lamp
Chicago Miniature Lamp
Table 5: AAT3683-2 Evaluation Board Bill of Materials.
Component
U1
R1
R2
R3, R4
R5, R6
C1, C2
C3
JP1
D1
D2
Part#
Description
Manufacturer
AAT3683IOQ-4.2-3
1A Linear Li-Ion Battery Charger;
2.2x2.2mm STDFN-10 Package
1.582KΩ, 1%, 1/4W; 0603
13.3KΩ, 1%, 1/4W; 0603
1.5KΩ, 5%, 1/4W; 0402
10KΩ, 1%, 1/4W; 0603
CER 10μF 6.3V 10% X5R 0603
CER 0.1μF 6.3V 10% X7R 0603
Conn. Header, 2mm zip
Green LED; 1206
Red LED; 1206
AnalogicTech
Chip Resistor
Chip Resistor
Chip Resistor
Chip Resistor
ECJ-1VB0J106M
GRM188R71C104KA01
PRPN401PAEN
CMD15-21VGC/TR8
CMD15-21SRC/TR8
Vishay
Vishay
Vishay
Vishay
Panansonic
Murata
Sullins Electronics
Chicago Miniature Lamp
Chicago Miniature Lamp
Table 6: AAT3683-3 Evaluation Board Bill of Materials.
Component
U1
R1
R2
R3, R4
R5, R6
C1, C2
C3
JP1
D1
D2
Part#
Description
Manufacturer
AAT3683IVN-4.2-4
1A Linear Li-Ion Battery Charger,
QFN33-16 Package
1.58KΩ, 1%, 1/4W 0603
13.3KΩ, 1%, 1/4W 0603
1.5KΩ, 5%, 1/4W 0402
10KΩ, 1%, 1/4W 0603
CER 10μF 10V 10% X5R 0805
CER 0.1μF 6.3V 10% X7R 0603
Conn. Header, 2mm zip
Green LED 1206
Red LED 1206
AnalogicTech
Chip Resistor
Chip Resistor
Chip Resistor
Chip Resistor
GRM21BR61A106KE19
GRM188R71C104KA01
PRPN401PAEN
CMD15-21VGC/TR8
CMD15-21SRC/TR8
Vishay
Vishay
Vishay
Vishay
Murata
Murata
Sullins Electronics
Chicago Miniature Lamp
Chicago Miniature Lamp
Table 7: AAT3683-4 Evaluation Board Bill of Materials.
3683.2007.06.1.0
21
AAT3683
1A Linear Li-Ion Battery Charger
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
STDFN-10 (2.2x2.2mm)
STDFN-10 (2.2x2.2mm)
QFN33-16
WIXYY
WJXYY
WKXYY
AAT3683IOQ-4.2-2-T1
AAT3683IOQ-4.2-3-T1
AAT3683IVN-4.2-4-T1
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
22
3683.2007.06.1.0
AAT3683
1A Linear Li-Ion Battery Charger
Package Information1
STDFN2.2x2.2-10
2.200 ± 0.050
1.000 ± 0.050
Top View
Detail "A"
1.710 ± 0.050
2.200 ± 0.050
Index Area
Bottom View
0.400 BSC
0.025 ± 0.025
0.152 REF
0.550 ± 0.050
0.350 ± 0.050
Side View
0.210 ± 0.050
Pin 1 Indicator
(optional)
R0.200
Detail "A"
All dimensions in millimeters.
1. 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.
3683.2007.06.1.0
23
AAT3683
1A Linear Li-Ion Battery Charger
QFN33-16
0.230 ± 0.050
Pin 1 Identification
0.500 ± 0.050
5
1.250 ± 0.050
C0.3
13
9
1.250 ± 0.050
Top View
Bottom View
0.025 ± 0.025
3.000 ± 0.050
0.214 ± 0.036
0.900 ± 0.100
0.400 ± 0.100
Pin 1 Dot By Marking
3.000 ± 0.050
1
Side View
All dimensions in millimeters.
© Advanced Analogic Technologies, Inc.
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work
rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Except as provided in AnalogicTech’s terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent,
copyright or other intellectual property right. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the
customer to minimize inherent or procedural hazards. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty.
Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated.
All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders.
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085
Phone (408) 737- 4600
Fax (408) 737- 4611
24
3683.2007.06.1.0