DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
General Description
Features
The AAT2557 is a fully integrated 500mA battery charger
and a 300mA low dropout (LDO) linear regulator. The
input voltage range is 4V to 6.5V for the battery charger
and 2.7V to 5.5V for the linear regulator, making it ideal
for applications operating with single-cell lithium-ion/
polymer batteries.
• Battery Charger:
▪ Input Voltage Range: 4V to 6.5V
▪ Programmable Charging Current up to 500mA
▪ Highly Integrated With
• Charging Device
• Reverse Blocking Diode
• Linear Regulator:
▪ 300mA Output Current
▪ Low Dropout: 400mV at 300mA
▪ Fast Line and Load Transient Response
▪ High Accuracy: ±1.5%
▪ 70µA Quiescent Current
• Short-Circuit, Over-Temperature, and Current Limit
Protection
• TSOPJW-14 Package
• -40°C to +85°C Temperature Range
The battery charger is a complete constant current/constant voltage linear charger. It offers an integrated pass
device, reverse blocking protection, high accuracy current and voltage regulation, charge status, and charge
termination. The charging current is programmable via
external resistor from 15mA to 500mA. In addition to
these standard features, the device offers over-voltage,
current limit, and thermal protection.
The linear regulator is designed for fast transient
response and good power supply ripple rejection.
Capable of up to 300mA load current, it includes shortcircuit protection and thermal shutdown.
Applications
•
•
•
•
•
•
The AAT2557 is available in a Pb-free, thermallyenhanced TSOPJW-14 package and is rated over the
-40°C to +85°C temperature range.
Bluetooth™ Headsets
Cellular and DECT Phones
Handheld Instruments
MP3 and Portable Music Players
PDAs and Handheld Computers
Portable Media Players
Typical Application
Adapter/USB Input
ADP
INLDO
STAT
C INLDO
EN_BAT
LDO Enable
EN_LDO
AAT2557
VOUTLDO
BATT+
BAT
C BAT
OUTLDO
C OUTLDO
ISET
BYP
C BYP
GND
System
Charger Enable
BATTRSET
Battery
Pack
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1
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Pin Descriptions
Pin #
Symbol
1
EN_LDO
2, 8, 12, 13, 14
GND
3
BYP
4
EN_BAT
5
ISET
6
7
9
10
11
BAT
ADP
STAT
OUTLDO
INLDO
Function
Enable pin for the linear regulator. When connected to logic low, the regulator is disabled and consumes less than 1µA of current. When connected to logic high, it resumes normal operation.
Ground.
Low noise bypass pin. Connect a 10nF capacitor between this pin and ground to improve AC ripple
rejection and reduce noise.
Enable pin for the battery charger. When connected to logic low, the battery charger is disabled
and consumes less than 1µA of current. When connected to logic high, the charger resumes normal operation.
Charge current set point. Connect a resistor from this pin to ground. Refer to typical characteristics
curves for resistor selection.
Battery charging and sensing.
Input for USB/adapter charger.
Charge status input. Open drain status output.
Linear regulator output. Connect a 2.2µF capacitor from this pin to ground.
Linear regulator input voltage. Connect a 1µF or greater capacitor from this pin to ground.
Pin Configuration
TSOPJW-14
(Top View)
EN_LDO
GND
BYP
EN_BAT
ISET
BAT
ADP
2
1
14
2
13
3
12
4
11
5
10
6
9
7
8
GND
GND
GND
INLDO
OUTLDO
STAT
GND
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DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Absolute Maximum Ratings1
Symbol
VINLDO
VADP
VEN
VX
VBYP
TJ
TA
TLEAD
Description
Input Voltage to GND
Adapter Voltage to GND
EN_LDO, EN_BAT Voltage to GND
BAT, ISET, STAT Voltage to GND
BYP Voltage to GND
Junction Temperature Range
Operating Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Value
Units
6.0
-0.3 to 7.5
-0.3 to 6.0
-0.3 to VADP + 0.3
-0.3 to VINLDO + 0.3
-40 to 150
-40 to 85
300
V
V
V
V
V
°C
°C
°C
Value
Units
625
160
mW
°C/W
Thermal Information
Symbol
PD
qJA
Description
Maximum Power Dissipation
Thermal Resistance2
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.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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3
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Electrical Characteristics1
VINLDO = VOUTLDO(NOM) + 1V for VOUTLDO options greater than 1.5V. IOUTLDO = 1mA, COUTLDO = 2.2µF, CINLDO = 1µF, CBYP = 10nF,
TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C.
Symbol
Description
Conditions
Min
Typ
Max
Units
-1.5
1.5
%
-2.5
2.5
VOUTLDO +
VDOLDO2
5.5
V
600
mV
Linear Regulator
VOUTLDO
Output Voltage Tolerance
VINLDO
Input Voltage
VDOLDO
DVOUT/
VOUTLDO*DVINLDO
Dropout Voltage
3
Line Regulation
DVOUTLDO(Line)
Dynamic Line Regulation
DVOUTLDO(Load)
Dynamic Load Regulation
IOUTLDO
ISC
IQLDO
ISHDN
Output Current
Short-Circuit Current
Quiescent Current
Shutdown Current
PSRR
Power Supply Rejection Ratio
TSD
THYS
eN
TC
TEN_LDO_DLY
VEN_LDO(L)
VEN_LDO(H)
IEN_LDO
Over-Temperature Shutdown Threshold
Over-Temperature Shutdown Hysteresis
Output Noise
Output Voltage Temperature Coefficient
LDO Enable Time Delay
LDO Enable Threshold Low
LDO Enable Threshold High
LDO Enable Input Current
IOUTLDO = 1mA to
300mA
TA = 25°C
TA = -40°C
to +85°C
IOUTLDO = 300mA
400
VINLDO = VOUTLDO + 1 to 5.0V
0.09
%/V
2.5
mV
60
mV
600
70
mA
mA
µA
µA
IOUTLDO = 300mA, VINLDO =
VOUTLDO + 1 to VOUTLDO + 2, TR/
TF = 2µs
IOUTLDO = 1mA to 300mA, TR
1.2V
VOUTLDO < 0.4V
VINLDO = 5V; VEN_LDO = VIN
VINLDO = 5V; VEN_LDO = 0V
1kHz
IOUTLDO =10mA
10kHz
1MHz
300
125
1.0
65
45
43
145
12
50
22
15
BYP Open
dB
0.6
1.5
VEN_LDO = 5.5V
1.0
°C
°C
µVRMS
ppm/°C
µs
V
V
µA
1. The AAT2557 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls.
2. VDO is defined as VIN - VOUT when VOUT is 98% of nominal.
3. For VOUT < 2.3V, VDO = 2.5V - VOUT.
4
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Electrical Characteristics1
VADP = 5V; TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C.
Symbol
Description
Battery Charger
Operation
VADP
Adapter Voltage Range
Under-Voltage Lockout (UVLO)
VUVLO
UVLO Hysteresis
IOP
Operating Current
ISHUTDOWN
Shutdown Current
ILEAKAGE
Reverse Leakage Current from BAT Pin
Voltage Regulation
VCO(REG)
Output Charge Voltage Regulation
DVCH/VCH
Output Charge Voltage Tolerance
VMIN
Preconditioning Voltage Threshold
VRCH
Battery Recharge Voltage Threshold
Current Regulation
ICH_CC
Charge Current Programmable Range
DICH_CC/ICH_CC Charge Current Regulation Tolerance
VISET
ISET Pin Voltage
KI_A
Current Set Factor: ICH/ISET
Charging Devices
RDS(ON)
Charging Transistor On Resistance
Logic Control/Protection
VEN_BAT(H)
Battery Charger Enable Threshold High
VEN_BAT(L)
Battery Charger Enable Threshold Low
VSTAT
STAT Pin Output Low Voltage
ISTAT
STAT Pin Current Sink Capability
VOVP
Battery Over-Voltage Protection Threshold
ICH_TKL/ICH_CC
Preconditioning Charge Current
ICH_TERM/ICH_CC Charge Termination Current
Conditions
Rising Edge
Min
Typ
4.0
3.0
Max
Units
6.5
4.0
V
V
mV
mA
µA
µA
150
0.5
0.3
0.4
Charge Current = 200mA
VBAT = 4.25V, EN_BAT = GND
VBAT = 4V, ADP Pin Open
4.158
2.85
4.20
0.5
3.0
1
1
2
4.242
3.15
VCO(REG) 0.1
Measured from VCO(REG)
15
V
500
mA
%
V
1.1
W
10
2
800
VADP = 5.5V
0.9
1.6
0.4
0.4
8
STAT Pin Sinks 4mA
ICH = 100mA
V
%
V
4.4
10
10
V
V
V
mA
V
%
%
1. The AAT2557 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202178A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 24, 2012
5
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Typical Characteristics – Battery Charger
Charging Current vs. Battery Voltage
Constant Charging Current
vs. Set Resistor Values
(VADP = 5V)
600
1000
RSET = 3.24kΩ
100
ICH (mA)
ICH (mA)
500
10
400
RSET = 5.36kΩ
300
RSET = 8.06kΩ
200
100
1
0
1
10
100
1000
2.7
2.9
RSET = 16.2kΩ
RSET = 31.6kΩ
3.1
3.7
3.3
RSET (kΩ)
3.5
3.9
4.1
4.3
VBAT (V)
Constant Output Charge Voltage
Regulation vs. Adapter Voltage
Constant Output Charge Voltage
Regulation vs. Temperature
(RSET = 8.06kΩ)
4.206
4.23
RSET = 8.06kΩ
4.22
4.202
4.200
VCO(REG) (V)
VCO_REG (V)
4.204
RSET = 31.6kΩ
4.198
4.196
4.194
4.5
4.75
5
5.25
5.5
5.75
6
6.25
-50
-25
0
25
50
75
100
Temperature (°C)
Constant Charging Current vs. Temperature
(RSET = 8.06kΩ)
(RSET = 8.06kΩ)
210
220
208
210
205
VBAT = 3.3V
ICH (mA)
ICH (mA)
4.19
4.17
6.5
Constant Charging Current vs.
Adapter Voltage
200
190
VBAT = 3.6V
VBAT = 4V
203
200
198
195
180
193
4
4.25
4.5
4.75
5
5.25
5.5
VADP (V)
6
4.20
4.18
VADP (V)
170
4.21
5.75
6
6.25
190
6.5
-50
-25
0
25
50
Temperature (°C)
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75
100
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Typical Characteristics – Battery Charger
Recharging Voltage Threshold
vs. Temperature
Preconditioning Voltage Threshold
vs. Temperature
(RSET = 8.06kΩ)
(RSET = 8.06kΩ)
4.18
3.03
4.16
3.02
VMIN (V)
VRCH (V)
4.14
4.12
4.10
4.08
3
2.99
4.06
2.98
4.04
4.02
3.01
-50
-25
0
25
50
75
2.97
-50
100
-25
0
Temperature (°C)
(RSET = 8.06kΩ)
ITRICKLE (mA)
ITRICKLE (mA)
20.4
20.2
20.0
19.8
19.6
RSET = 5.36kΩ
30
RSET = 8.06kΩ
20
0
25
50
75
100
Temperature (°C)
RSET = 31.6kΩ
RSET = 16.2kΩ
4
4.2
4.4
4.6
4.8
5
5.2
5.4
5.6
5.8
6
6.2
6.4
VADP (V)
Operating Current vs. Temperature
Sleep Mode Current vs. Supply Voltage
(RSET = 8.06kΩ)
(RSET = 8.06kΩ)
800
550
700
500
450
400
500
400
300
25°C
200
350
300
-50
85°C
600
ISLEEP (nA)
IOP (µA)
40
10
19.4
0
100
RSET = 3.24kΩ
50
20.6
-25
75
60
20.8
-50
50
Preconditioning Charge Current
vs. Adapter Voltage
Preconditioning Charge Current
vs. Temperature
19.2
25
Temperature (°C)
-40°C
100
-25
0
25
50
Temperature (°C)
75
0
100
4
4.25
4.5
4.75
5
5.25
5.5
5.75
6
6.25
6.5
VADP (V)
25°C
85°C
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-40°C
7
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Typical Characteristics – Battery Charger
Enable Input High Voltage vs. Adapter Voltage
Enable Input Low Voltage vs. Adapter Voltage
(RSET = 8.06kΩ)
(RSET = 8.06kΩ)
1.2
1.1
1
0.9
25°C
0.8
0.7
85°C
0.9
0.8
4.25
4.5
4.75
5
5.25
5.5
5.75
6
25°C
0.7
0.6
4
-40°C
1
-40°C
VEN_BAT(L) (V)
VEN_BAT(H) (V)
1.1
6.25
6.5
VADP (V)
4
4.25
4.5
4.75
5
5.25
5.5
85°C
5.75
6
6.25
6.5
VADP (V)
Typical Characteristics – LDO Regulator
Dropout Voltage vs. Temperature
1.250
540
1.225
480
Dropout Voltage (mV)
VEN_LDO(L) and VEN_LDO(H) (V)
Enable Input High and Low Voltages
vs. Input Voltage
1.200
VEN(H)
1.175
1.150
1.125
VEN(L)
1.100
1.075
1.050
2.5
3.0
3.5
4.0
4.5
5.0
360
300
180
120
60
Input Voltage (V)
IL = 50mA
-40 -30 -20 -10 0
Dropout Voltage vs. Output Current
3.2
IOUT = 300mA
IOUT = 150mA
2.6
2.4
2.0
2.7
IOUT = 10mA
IOUT = 100mA
IOUT = 50mA
450
400
350
300
2.9
3.0
3.1
3.2
3.3
85°C
250
200
150
-40°C
100
25°C
50
0
2.8
Input Voltage (V)
8
Dropout Voltage (mV)
Output Voltage (V)
500
IOUT = 0mA
2.8
2.2
10 20 30 40 50 60 70 80 90 100 110 120
Temperature (°C)
Dropout Characteristics
3.0
IL = 100mA
IL = 150mA
240
0
5.5
IL = 300mA
420
0
50
100
150
200
Output Current (mA)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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250
300
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Typical Characteristics – LDO Regulator
Quiescent Current vs. Temperature
Ground Current vs. Input Voltage
90
100
Quiescent Current (µA)
Ground Current (µA)
80
70
60
IOUT=300mA
50
IOUT=150mA
IOUT=50mA
40
IOUT=0mA
30
IOUT=10mA
20
10
0
90
80
70
60
50
40
30
20
10
0
2
2.5
3
3.5
4
4.5
-40 -30 -20 -10
5
Input Voltage (V)
LDO Initial Turn-On Response Time
1.202
5
Input Voltage (top) (V)
Output Voltage (V)
6
1.201
1.200
1.199
1.198
1.197
10 20
30
40
50 60
70 80
4
3
2
3
1
2
0
1
0
90 100
Time (50µs/div)
Temperature (°C)
LDO Turn-Off Response Time
LDO Turn-On Time from Enable
(IOUT = 100mA)
(VIN Present)
4
1
3
0
2
1
0
Enable Voltage (top) (V)
Enable Voltage (top) (V)
2
5
0
3
2
1
0
Output Voltage (bottom) (V)
3
Output Voltage (bottom) (V)
4
Time (5µs/div)
Output Voltage (bottom) (V)
1.203
0
10 20 30 40 50 60 70 80 90 100 110 120
Temperature (°C)
Output Voltage vs. Temperature
1.196
-40 -30 -20 -10
0
Time (5µs/div)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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9
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Typical Characteristics – LDO Regulator
Load Transient Response
Line Transient Response
(VOUT = 2.8V)
VIN
4
3.00
VOUT
2.99
2.98
Time (100µs/div)
Output Voltage (top) (V)
5
Output Voltage (bottom) (V)
Input Voltage (top) (V)
6
2.85
VOUT
2.80
2.75
100
0
IOUT
Time (100µs/div)
Load Transient Response 300mA
3.0
2.9
2.8
2.7
VOUT
400
300
200
IOUT
100
0
Output Current (bottom) (mA)
Output Voltage (top) (V)
(VOUT = 2.8V)
Time (10µs/div)
10
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Output Current (bottom) (mA)
2.90
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Functional Block Diagram
Reverse Blocking
BAT
ADP
OverTemperature
Protection
Charge
Control
-
STAT
Constant
Current
+
+
ISET
-
VREF
UVLO
EN_BAT
INLDO
Err.
Amp.
BYP
VREF
OverCurrent
Protection
OUTLDO
EN_LDO
Functional Description
The AAT2557 is a high performance power management
IC comprised of a lithium-ion/polymer battery charger
and a linear regulator.
Battery Charger
The battery charger is designed for single-cell lithiumion/polymer batteries using a constant current and constant voltage algorithm. The battery charger operates
from the adapter/USB input voltage range from 4V to
6.5V. The adapter/USB charging current level can be
programmed up to 500mA for rapid charging applications. A status monitor output pin is provided to indicate
GND
the battery charge state by directly driving one external
LED. Internal device temperature and charging state are
fully monitored for fault conditions. Fault condition can
be one of the following:
• Battery over-voltage (OV)
• Battery temperature sense hot or cold
• Battery charge timer time-out
• Chip thermal shutdown
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. Other features include an integrated
reverse blocking diode and sense resistor.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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11
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Linear Regulator
Protection Circuitry
The advanced circuit design of the linear regulator has
been specifically optimized for very fast start-up. This
proprietary CMOS LDO has also been tailored for superior transient response characteristics. These traits are
particularly important for applications that require fast
power supply timing.
Over-Voltage Protection
The high-speed turn-on capability is enabled through
implementation of a fast-start control circuit which
accelerates the power-up behavior of fundamental control and feedback circuits within the LDO regulator. The
LDO regulator output has been specifically optimized to
function with low-cost, low-ESR ceramic capacitors;
however, the design will allow for operation over a wide
range of capacitor types.
The regulator comes with complete short-circuit and thermal protection. The combination of these two internal
protection circuits gives a comprehensive safety system
to guard against extreme adverse operating conditions.
The regulator features an enable/disable function. The
EN_LDO pin is active high and is compatible with CMOS
logic levels. To assure the LDO regulator will turn on, the
EN_LDO control level must be greater than 1.5V. The
LDO regulator will be disabled when the voltage on the
EN_LDO pin falls below 0.6V. If the enable function is not
needed in a specific application, it may be tied to INLDO
to keep the LDO regulator in a continuously on state.
Battery Charger Under-Voltage Lockout
The AAT2557 has internal circuits for UVLO and power
on reset features. If the ADP supply voltage drops below
the UVLO threshold, the battery charger will suspend
charging and shut down. When power is reapplied to the
ADP pin or the UVLO condition recovers, the system
charge control will automatically resume charging in the
appropriate mode for the condition of the battery.
12
When the voltage on the BAT pin exceeds the overvoltage protection threshold (VOVP = 4.4V) it is defined
as an over-voltage protection event. If this over-voltage
condition occurs, the charger control circuitry will shut
down the device. The charger will resume normal charging operation after the over-voltage condition is
removed.
Over-Temperature Protection
The AAT2557’s battery charger has a thermal protection
circuit which will shut down charging functions when the
internal die temperature exceeds the preset thermal
limit threshold (145°C). Once the internal die temperature falls below the thermal limit, normal charging
operation will resume. The AAT2557’s LDO also has an
internal thermal protection circuit which will turn on
when the device die temperature exceeds 145°C. The
internal thermal protection circuit will actively turn off
the LDO regulator output pass device to prevent the
possibility of over temperature damage. The LDO regulator output will remain in a shutdown state until the
internal die temperature falls back to 12°C below the
145°C trip point.
Short-Circuit Protection
The AAT2557’s LDO contains an internal short-circuit
protection circuit that will trigger when the output load
current exceeds the internal threshold limit. Under
short-circuit conditions, the output of the LDO regulator
will be current limited until the short-circuit condition is
removed from the output or until the package power dissipation exceeds the device thermal limit.
The combination and interaction between the short-circuit and thermal protection systems allow the LDO regulator to withstand indefinite short-circuit conditions
without sustaining permanent damage.
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DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Battery Charging Operation
Battery charging commences only after checking several
conditions in order to maintain a safe charging environment. The input supply (ADP) must be above the minimum operating voltage (UVLO) and the enable pin must
be high (internally pulled down). When the battery is
connected to the BAT pin, the charger checks the condition of the battery and determines which charging mode
to apply. If the battery voltage is below VMIN, the charger
begins battery pre-conditioning by charging at 10% of
the programmed constant current; e.g., if the programmed current is 150mA, then the pre-conditioning
current (trickle charge) is 15mA. Pre-conditioning is
purely a safety precaution for a deeply discharged cell
and will also reduce the power dissipation in the internal
series MOSFET pass device when the input-output voltage differential is at its highest.
Pre-conditioning continues until the battery voltage
reaches VMIN (see Figure 1). At this point, the charger
begins constant-current charging. The current level for
this mode is programmed using a single resistor from
Battery
UVLO
Trickle
Charge
Constant Current
Charge Phase (CC)
the ISET pin to ground. Programmed current can be set
from a minimum 15mA up to a maximum of 500mA.
Constant current charging will continue until the battery
voltage reaches the voltage regulation point, VBAT and
the battery charger begins constant voltage mode. The
regulation voltage is factory programmed to a nominal
4.2V and will continue charging until the charging current has reduced to 10% of the programmed current.
After the charge cycle is complete, the pass device turns
off and the device automatically goes into a power-saving sleep mode. During this time, the series pass device
will block current in both directions, preventing the battery from discharging through the IC.
The battery charger will remain in sleep mode, even if
the charger source is disconnected, until one of the following events occurs: the battery terminal voltage drops
below the VRCH threshold; the charger EN pin is recycled;
or the charging source is reconnected. In all cases, the
charger will monitor all parameters and resume charging
in the most appropriate mode.
Constant Voltage Charge
Phase (CV)
Constant Current
Charge Phase
Constant Voltage Charge
Phase
Recharge Phase
ICH_CC
Termination
Phase
I CH_ CC
Termination
Phase
VCO( REG)
VRCH
VMIN
I CH_ TERM
when
VUVLO
I CH_ TKL
VBAT =
VCO( REG)
I CH_ TERM
when
VBAT =
VCO( REG)
Figure 1: Current vs. Voltage Profile During Charging Phases.
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13
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Battery Charging System Operation Flow Chart
Enable
No
Power On Reset
Yes
Power Input
Voltage
VADP > VUVLO
Yes
Shut Down
Yes
Fault Conditions
Monitoring
OV, OT
Charge
Control
No
Preconditioning
Test
V MIN > VBAT
Yes
Preconditioning
(Trickle Charge)
Yes
Constant
Current Charge
Mode
Yes
Constant
Voltage Charge
Mode
No
No
Recharge Test
V RCH > VBAT
Yes
Current Phase Test
V CO(REG) > VBAT
No
Voltage Phase Test
IBAT > ICH_TERM
No
Charge Completed
14
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DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Application Information
Soft Start / Enable
The EN_BAT pin is internally pulled down. When pulled
to a logic high level, the battery charger is enabled.
When left open or pulled to a logic low level, the battery
charger is shut down and forced into the sleep state.
Charging will be halted regardless of the battery voltage
or charging state. When it 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 from
the BAT pin.
Event Description
Status
No battery charging activity
Battery charging via adapter or USB port
Charging completed
OFF
ON
OFF
Table 1: LED Status Indicator.
Constant Charge
Current ICH_CC (mA)
Set Resistor Value
(kW)
500
400
300
250
200
150
100
50
40
30
20
15
3.24
4.12
5.36
6.49
8.06
10.7
16.2
31.6
38.3
53.6
78.7
105
The LDO is enabled when the EN_LDO pin is pulled high.
The control and feedback circuits have been optimized
for high-speed, monotonic turn-on characteristics.
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 battery charger will operate
from the adapter input over a 4.0V to 6.5V range.
The fast charge constant current charge level is user
programmable 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
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. Fast charge constant current levels from 15mA to 500mA may be set by
selecting the appropriate resistor value from Table 2.
Charge Status Output
The AAT2557 provides battery charge status via a status
pin. This pin is internally connected to an N-channel
open drain MOSFET, which can be used to drive an external LED. The status pin can indicate several conditions,
as shown in Table 1.
1000
ICH_CC (mA)
Programming Charge Current
Table 2: RSET Values.
100
10
1
1
10
100
1000
RSET (kΩ)
Figure 2: Constant Charging Current
vs. Set Resistor Values.
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 lowcost green or red LEDs. It is not recommended to exceed
8mA for driving an individual status LED.
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15
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
The required ballast resistor values can be estimated
using the following formulas:
R1=
(VADP - VF(LED))
ILED
Example:
R1 =
(5.5V - 2.0V)
= 1.75kΩ
2mA
Note: Red LED forward voltage (VF) is typically 2.0V @
2mA.
Thermal Considerations
The AAT2557 is offered in a TSOPJW-14 package which
can provide up to 625mW of power dissipation when it
is properly bonded to a printed circuit board and has a
maximum thermal resistance of 160°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 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:
Where:
PD
VADP
VBAT
ICH
=
=
=
=
Total Power Dissipation by the Device
ADP/USB Voltage
Battery Voltage as Seen at the BAT Pin
Constant Charge Current Programmed for the
Application
IOP
=
Quiescent Current Consumed by the Charger
IC for Normal Operation [0.5mA]
VINLDO = Input Voltage as Seen at the INLDO Pin
VOUTLDO = Output Voltage as Seen at the OUTLDO Pin
IOUTLDO = LDO Load Current
IQLDO = LDO Quiescent Current
By substitution, we can derive the maximum charge current before reaching the thermal limit condition (thermal
cycling). The maximum charge current is the key factor
when designing battery charger applications.
ICH(MAX) =
(PD(MAX) - VIN · IOP)
VIN - VBAT
(TJ(MAX) - TA) - V · I
IN
OP
θJA
ICH(MAX) =
VIN - VBAT
In general, the worst condition is the greatest voltage
drop across the IC, when battery voltage is charged up
to the preconditioning voltage threshold.
Capacitor Selection
Linear Regulator Input Capacitor
(TJ(MAX) - TA)
PD(MAX) =
θJA
Where:
PD(MAX) = Maximum Power Dissipation (W)
qJA
= Package Thermal Resistance (°C/W)
TJ(MAX) = Maximum Device Junction Temperature (°C)
[135°C]
TA
= Ambient Temperature (°C)
PD = [(VADP - VBAT) · ICH + (VADP · IOP)] + (VINLDO - VOUTLDO) IOUTLDO + VINLDO · IQLDO
16
An input capacitor greater than 1µF will offer superior
input line transient response and maximize power supply ripple rejection. Ceramic, tantalum, or aluminum
electrolytic capacitors may be selected since there is no
specific capacitor ESR requirement for CINLDO. However,
for best performance of the LDO regulator at maximum
load current output, ceramic capacitors are recommended for CINLDO due to their inherent capability over tantalum capacitors to withstand input current surges from
low impedance sources such as batteries in portable
devices.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Battery Charger Input Capacitor
In general, it is good design practice to place a decoupling capacitor between the ADP 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
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 CADP 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.
Linear Regulator Output Capacitor
For proper load voltage regulation and operational stability, a capacitor is required between OUT and GND. The
COUTLDO capacitor connection to the LDO regulator ground
pin should be made as directly as practically possible for
maximum device performance. Since the regulator has
been designed to function with very low ESR capacitors,
ceramic capacitors in the 1.0µF to 10µF range are recommended for best performance. Applications utilizing
the exceptionally low output noise and optimum power
supply ripple rejection should use 2.2µF or greater for
COUTLDO. In low output current applications, where output
load is less than 10mA, the minimum value for COUTLDO
can be as low as 0.47µF.
may be required to prevent the device from cycling on
and off when no battery is present.
Bypass Capacitor and Low Noise Applications
A bypass capacitor pin is provided to enhance the low
noise characteristics of the AAT2557 LDO regulator. The
bypass capacitor is not necessary for operation of the
AAT2557. However, for best device performance, a small
ceramic capacitor should be placed between the bypass
pin (BYP) and the device ground pin (GND). The value of
CBYP may range from 470pF to 10nF. For lowest noise and
best possible power supply ripple rejection performance,
a 10nF capacitor should be used. To practically realize
the highest power supply ripple rejection and lowest
output noise performance, it is critical that the capacitor
connection between the BYP pin and GND pin be direct
and PCB traces should be as short as possible. Refer to
the PCB Layout Recommendations section of this document for examples.
There is a relationship between the bypass capacitor
value and the LDO regulator turn-on and turnoff time. In
applications where fast device turn-on and turn-off time
are desired, the value of CBYP should be reduced.
In applications where low noise performance and/or
ripple rejection are less of a concern, the bypass capacitor may be omitted. The fastest device turn-on time will
be realized when no bypass capacitor is used.
Battery Charger Output Capacitor
Printed Circuit Board
Layout Considerations
The AAT2557 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
AAT2557 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
For the best results, it is recommended to physically
place the battery pack as close as possible to the
AAT2557 BAT pin. To minimize voltage drops on the PCB,
keep the high current carrying traces adequately wide.
The input capacitors should connect as closely as possible to ADP and INLDO.
Manufacturer
Part Number
Value (µF)
Voltage Rating
Temp. Co.
Case Size
Murata
Murata
Murata
Murata
Murata
Murata
Murata
Murata
GRM21BR61A106KE19
GRM188R60J475KE19
GRM188R61A225KE34
GRM188R60J225KE19
GRM188R61A105KA61
GRM185R60J105KE26
GRM188F51H103ZA01
GRM155F51H103ZA01
10
4.7
2.2
2.2
1.0
1.0
0.01
0.01
10
6.3
10
6.3
10
6.3
50
50
X5R
X5R
X5R
X5R
X5R
X5R
Y5V
Y5V
0805
0603
0603
0603
0603
0603
0603
0402
Table 3: Surface Mount Capacitors.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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17
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Figure 3: AAT2557 Evaluation Board
Top Side Layout.
ADP
TB1
Figure 4: AAT2557 Evaluation Board
Bottom Side Layout.
7
GND R2 1.5k
JP2
JP3
INLDO
1
GND
10
JP1
INLDO
INLDO
C3
4.7µF
GND
EN_BAT
BAT
TB2
BAT
6
EN_LDO
OUTLDO
BYP
14
13
12
8
2
C4
2.2µF
11
STAT
GND
GND
GND
GND
GND
GND
3
TP1
INLDO
AAT2557ITO
9
4
EN_LDO
TSOPJW-14
ADP
C1
10µF
D1
GND
U1
C5
10nF
ISET
C2
10µF
5
R1
8.06k
GND
Figure 5: AAT2557 Evaluation Board Schematic.
18
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
TSOPJW-14
TSOPJW-14
VKXYY
9ZXYY
AAT2557ITO-CT-T1
AAT2557ITO-CW-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.
Legend
Voltage
Code
1.2
1.5
1.8
1.9
2.5
2.6
2.7
2.8
2.85
2.9
3.0
3.3
4.2
E
G
I
Y
N
O
P
Q
R
S
T
W
C
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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19
DATA SHEET
AAT2557
500mA Battery Charger and 300mA LDO Regulator for Portable Systems
Package Information
TSOPJW-14
2.85 ± 0.20
2.40 ± 0.10
0.20 +- 0.10
0.05
0.40 BSC
Top View
0.04 REF
0.05 +- 0.05
0.04
Side View
0.15 ± 0.05
+ 0.05
1.05 - 0.00
+ 0.000
1.00 - 0.075
3.05 +- 0.05
0.10
4° ± 4°
0.45 ± 0.15
2.75 ± 0.25
End View
All dimensions in millimeters.
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. Skyworks may change its documentation, products, services, specifications 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 conflicts, incompatibilities, or other difficulties 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 hereunder, 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, INCLUDING 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 environmental 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 specifications as a result of design defects, errors, or operation of products outside of published parameters or design specifications. 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 specifications 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
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20
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