AAT2556 [SKYWORKS]
Battery Charger and Step-Down Converter for Portable Applications; 电池充电器和降压型转换器，用于便携式应用
| 型号： | AAT2556 |
| 厂家： | 
SKYWORKS SOLUTIONS INC. |
| 描述： | Battery Charger and Step-Down Converter for Portable Applications |
| 文件： | 总27页 (文件大小：2371K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
General Description
Features
•
The AAT2556 is a member of Skyworks' Total Power
Management IC (TPMIC™) product family. It is a fully
integrated 500mA battery charger plus a 250mA step-
down converter. The input voltage range is 4V to 6.5V for
the battery charger and 2.7V to 5.5V for the step-down
converter, making it ideal for single-cell lithium-ion/poly-
mer battery-powered applications.
Battery Charger:
Input Voltage Range: 4V to 6.5V
Programmable Charging Current up to 500mA
Highly Integrated Battery Charger
▪
▪
▪
Charging Device
Reverse Blocking Diode
▪
▪
•
Step-Down Converter:
Input Voltage Range: 2.7V to 5.5V
Output Voltage Range: 0.6V to VIN
250mA Output Current
Up to 96% Efficiency
30μA Quiescent Current
1.5MHz Switching Frequency
▪
The battery charger is a complete constant current/ con-
stant voltage linear charger. It offers an integrated pass
device, reverse blocking protection, high current accu-
racy and voltage regulation, charge status, and charge
termination. The charging current is programmable via
external resistor from 15mA to 500mA. In addition to
standard features, the device offers over-voltage, cur-
rent limit, and thermal protection.
▪
▪
▪
▪
▪
100μs Start-Up Time
Short-Circuit, Over-Temperature, and Current Limit
Protection
▪
•
•
•
The step-down converter is a highly integrated converter
operating at 1.5MHz of switching frequency, minimizing
the size of external components while keeping switching
losses low. It has independent input and enable pins.
The output voltage ranges from 0.6V to the input volt-
age. The feedback and control deliver excellent load
regulation and transient response with a small output
inductor and capacitor.
TDFN33-12 Package
-40°C to +85°C Temperature Range
Applications
•
•
•
•
•
•
Bluetooth™ Headsets
Cellular Phones
Handheld Instruments
MP3 and Portable Music Players
PDAs and Handheld Computers
Portable Media Players
The AAT2556 is available in a Pb-free, thermally-
enhanced TDFN33-12 package and is rated over the
-40°C to +85°C temperature range.
Typical Application
Adapter / USB Input
ADP
VIN
EN_BUCK
BAT
STAT
BATT +
Enable
EN_BAT
VOUT
L= 3.3μH
RFB1
C
LX
FB
BATT -
ISET
COUT
RSET
RFB2
GND
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Pin Descriptions
Pin #
Symbol Function
1
FB
GND
Feedback input. This pin must be connected directly to an external resistor divider. Nominal voltage is 0.6V.
Ground.
2, 8, 10
Enable pin for the step-down converter. When connected to logic low, the step-down converter is disabled
and it consumes less than 1μA of current. When connected to logic high, it resumes normal operation.
Enable pin for the battery charger. When internally pulled down, the battery charger is disabled and it con-
sumes less than 1μA of current. When connected to logic high, it resumes normal operation.
Charge current set point. Connect a resistor from this pin to ground. Refer to typical curves for resistor
selection.
3
4
5
EN_BUCK
EN_BAT
ISET
6
7
9
BAT
STAT
ADP
Battery charging and sensing.
Charge status input. Open drain status input.
Input for USB/adapter charger.
Output of the step-down converter. Connect the inductor to this pin. Internally, it is connected to the drain
of both high- and low-side MOSFETs.
11
LX
12
EP
VIN
Input voltage for the step-down converter.
Exposed paddle (bottom): connect to ground directly beneath the package.
Pin Configuration
TDFN33-12
(Top View)
1
2
3
4
5
6
12
11
10
9
FB
GND
EN_BUCK
EN_BAT
ISET
VIN
LX
GND
ADP
GND
STAT
8
7
BAT
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Absolute Maximum Ratings1
Symbol
Description
Value
Units
VIN
VADP
VLX
VFB
VEN
VX
Input Voltage to GND
Adapter Voltage to GND
LX to GND
FB to GND
EN_BAT and EN_BUCK to GND
BAT, ISET and STAT to GND
Operating Junction Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
6.0
-0.3 to 7.5
V
V
V
V
V
V
°C
°C
-0.3 to VIN + 0.3
-0.3 to VIN + 0.3
-0.3 to 6.0
-0.3 to VADP + 0.3
-40 to 150
TJ
TLEAD
300
Thermal Information
Symbol
Description
Value
Units
PD
JA
Maximum Power Dissipation
Thermal Resistance2
2.0
50
W
°C/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.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Electrical Characteristics1
VIN = 3.6V; TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C.
Symbol Description
Step-Down Converter
Conditions
Min
Typ
Max Units
VIN
Input Voltage
2.7
5.5
2.7
V
V
VIN Rising
VUVLO
UVLO Threshold
Hysteresis
VIN Falling
IOUT = 0 to 250mA, VIN = 2.7V to 5.5V
200
mV
V
%
V
μA
μA
mA
1.8
-3.0
0.6
VOUT
VOUT
IQ
ISHDN
ILIM
RDS(ON)H
RDS(ON)L
ILXLEAK
Output Voltage Tolerance2
Output Voltage Range
Quiescent Current
3.0
VIN
No Load
EN = GND
30
Shutdown Current
1.0
P-Channel Current Limit
High-Side Switch On Resistance
Low-Side Switch On Resistance
LX Leakage Current
600
0.59
0.42
μA
VIN = 5.5V, VLX = 0 to VIN
VIN = 2.7V to 5.5V
1.0
VLinereg
VIN
/
Line Regulation
0.2
%/V
VFB
IFB
FOSC
TS
Feedback Threshold Voltage Accuracy
FB Leakage Current
Oscillator Frequency
VIN = 3.6V
VOUT = 1.0V
0.591 0.600 0.609
V
μA
MHz
μs
°C
°C
V
0.2
1.5
100
140
15
0.6
Startup Time
From Enable to Output Regulation
TSD
Over-Temperature Shutdown Threshold
Over-Temperature Shutdown Hysteresis
Enable Threshold Low
Enable Threshold High
Input Low Current
THYS
VEN(L)
VEN(H)
IEN
1.4
V
μA
VIN = VEN = 5.5V
-1.0
1.0
1. The AAT2556 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correla-
tion with statistical process controls.
2. Output voltage tolerance is independent of feedback resistor network accuracy.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Electrical Characteristics1
VADP = 5V; TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C.
Symbol
Description
Conditions
Min
Typ
Max
Units
Battery Charger
Operation
VADP
VUVLO
Adapter Voltage Range
Under-Voltage Lockout (UVLO)
UVLO Hysteresis
Operating Current
Shutdown Current
4.0
3
6.5
4
V
V
mV
mA
μA
μA
Rising Edge
150
0.5
0.3
0.4
IOP
ISHUTDOWN
ILEAKAGE
Charge Current = 200mA
VBAT = 4.25V, EN = GND
VBAT = 4V, ADP Pin Open
1
1
2
Reverse Leakage Current from BAT Pin
Voltage Regulation
VBAT_EOC
VCH/VCH
VMIN
End of Charge Accuracy
4.158
2.85
4.20
0.5
3.0
4.242
3.15
V
%
V
Output Charge Voltage Tolerance
Preconditioning Voltage Threshold
Battery Recharge Voltage Threshold
VRCH
Measured from VBAT_EOC
-0.1
V
Current Regulation
ICH
ICH/ICH
VSET
Charge Current Programmable Range
Charge Current Regulation Tolerance
ISET Pin Voltage
15
500
1.1
mA
%
V
10
2
800
KI_A
Current Set Factor: ICH/ISET
Charging Devices
RDS(ON)
Charging Transistor On Resistance
VADP = 5.5V
0.9
Logic Control/Protection
VEN(H)
VEN(L)
VSTAT
ISTAT
VOVP
Input High Threshold
Input Low Threshold
Output Low Voltage
STAT Pin Current Sink Capability
Over-Voltage Protection Threshold
Pre-Charge Current
1.6
V
V
V
mA
V
%
%
0.4
0.4
8
STAT Pin Sinks 4mA
ICH = 100mA
4.4
10
10
ITK/ICHG
TERM/ICHG
I
Charge Termination Threshold Current
1. The AAT2556 output charge voltage is specified over the 0° to 70°C ambient temperature range; operation over the -25°C to +85°C temperature range is guaranteed by
design.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Typical Characteristics – Step-Down Converter
Efficiency vs. Load
(VOUT = 1.8V; L = 3.3µH)
DC Load Regulation
(VOUT = 1.8V; L = 3.3µH)
100
90
80
70
60
50
40
1.0
0.5
VIN = 5.0V
VIN = 2.7V
VIN = 3.6V
VIN = 3.6V
VIN = 5.5V
VIN = 5.5V
0.0
VIN = 2.7V
VIN = 4.2V
VIN = 5.0V
VIN = 4.2V
-0.5
-1.0
0.1
1
10
100
1000
0.1
1
10
100
1000
Output Current (mA)
Output Current (mA)
Efficiency vs. Load
(VOUT = 1.2V; L = 1.5µH)
DC Load Regulation
(VOUT = 1.2V; L = 1.5µH)
100
90
80
70
60
50
40
30
1.0
0.5
VIN = 2.7V
VIN = 5.0V
VIN = 3.6V
VIN = 5.5V
0.0
VIN = 5.5V
VIN = 5.0V
VIN = 4.2V
VIN = 3.6V
VIN = 4.2V
-0.5
-1.0
VIN = 2.7V
0.1
1
10
100
1000
0.1
1
10
100
1000
Output Current (mA)
Output Current (mA)
Soft Start
(VIN = 3.6V; VOUT = 1.8V;
IOUT = 250mA; CFF = 100pF)
Line Regulation
(VOUT = 1.8V)
0.6
0.5
0.4
0.3
0.2
0.1
0.0
-0.1
-0.2
-0.3
5.0
4.0
3.0
2.0
1.0
0.0
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
VEN
IOUT = 0mA
IOUT = 50mA
IOUT = 150mA
-1.0
-2.0
-3.0
-4.0
-5.0
VO
IOUT = 10mA
IOUT = 250mA
IL
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Time (100µs/div)
Input Voltage (V)
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Typical Characteristics – Step-Down Converter
Output Voltage Error vs. Temperature
(VIN = 3.6V; VOUT = 1.8V; IOUT = 250mA)
Switching Frequency Variation
vs. Temperature
(VIN = 3.6V; VOUT = 1.8V)
3.0
2.0
10.0
8.0
6.0
1.0
4.0
2.0
0.0
0.0
-2.0
-4.0
-6.0
-8.0
-10.0
-1.0
-2.0
-3.0
-40
-20
0
20
40
60
80
100
5.5
6.0
-40
-20
0
20
40
60
80
100
Temperature (°°C)
Temperature (°°C)
Frequency Variation vs. Input Voltage
(VOUT = 1.8V)
No Load Quiescent Current vs. Input Voltage
50
45
40
2.0
1.0
0.0
85°C
35
-1.0
-2.0
-3.0
-4.0
30
25°C
25
-40°C
20
15
10
2.7
3.1
3.5
3.9
4.3
4.7
5.1
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
Input Voltage (V)
Input Voltage (V)
P-Channel RDS(ON) vs. Input Voltage
N-Channel RDS(ON) vs. Input Voltage
750
1000
900
800
700
600
500
400
300
700
650
600
550
500
450
400
350
300
120°C 100°C
85°C
120°C
100°C
85°C
25°C
25°C
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Input Voltage (V)
Input Voltage (V)
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Typical Characteristics – Step-Down Converter
Load Transient Response
(10mA to 250mA; VIN = 3.6V; VOUT = 1.8V;
COUT = 4.7µF; CFF = 100pF)
Load Transient Response
(10mA to 250mA; VIN = 3.6V; VOUT = 1.8V; COUT = 4.7µF)
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
VO
VO
IO
IO
ILX
ILX
Time (25µs/div)
Time (25µs/div)
Line Response
(VOUT = 1.8V @ 250mA; CFF = 100pF)
Output Ripple
(VIN = 3.6V; VOUT = 1.8V; IOUT = 1mA)
40
20
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0.00
-0.01
1.90
1.85
1.80
1.75
1.70
1.65
1.60
1.55
1.50
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
VO
VO
0
-20
-40
-60
-80
-100
-120
VIN
IL
Time (25µs/div)
Time (2µs/div)
Output Ripple
(VIN = 3.6V; VOUT = 1.8V; IOUT = 250mA)
40
20
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
VO
0
-20
-40
-60
-80
-100
-120
IL
Time (200ns/div)
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Typical Characteristics – Battery Charger
Constant Charging Current
vs. Set Resistor Values
Charging Current vs. Battery Voltage
(VADP = 5V)
600
500
400
300
200
100
0
1000
100
10
RSET = 3.24kΩ
RSET = 5.36kΩ
RSET = 8.06kΩ
RSET = 31.6kΩ
RSET = 16.2kΩ
1
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
1
10
100
1000
V
BAT (V)
RSET (kΩ)
End of Charge Battery Voltage
vs. Supply Voltage
End of Charge Voltage Regulation
vs. Temperature
(RSET = 8.06kΩ)
4.206
4.204
4.202
4.200
4.198
4.196
4.194
4.23
4.22
4.21
4.20
4.19
4.18
4.17
RSET = 8.06kΩ
RSET = 31.6kΩ
4.5
4.75
5
5.25
5.5
5.75
6
6.25
6.5
-50
-25
0
25
50
75
100
VADP (V)
Temperature (°C)
Constant Charging Current vs.
Supply Voltage
Constant Charging Current vs. Temperature
(RSET = 8.06kΩ)
(RSET = 8.06kΩ)
210
208
205
203
200
198
195
193
190
220
210
200
190
180
VBAT = 3.3V
VBAT = 4V
VBAT = 3.6V
170
4
-50
-25
0
25
50
75
100
4.25 4.5 4.75
5
5.25 5.5 5.75
6
6.25 6.5
V
ADP (V)
Temperature (°C)
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Typical Characteristics – Battery Charger
Operating Current vs. Temperature
(RSET = 8.06kΩ)
Preconditioning Threshold Voltage
vs. Temperature
(RSET = 8.06kΩ)
550
500
450
400
350
300
3.03
3.02
3.01
3
2.99
2.98
2.97
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
Temperature (°C)
Temperature (°C)
Preconditioning Charge Current
vs. Temperature
Preconditioning Charge Current
vs. Supply Voltage
(RSET = 8.06kΩ)
60
20.8
20.6
20.4
20.2
20.0
19.8
19.6
19.4
19.2
RSET = 3.24kΩ
50
40
30
20
10
0
RSET = 5.36kΩ
RSET = 8.06kΩ
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
-50
-25
0
25
50
75
100
Temperature (°C)
VADP (V)
Recharging Threshold Voltage
vs. Temperature
Sleep Mode Current vs. Supply Voltage
(RSET = 8.06kΩ)
(RSET = 8.06kΩ)
800
700
600
500
400
300
200
100
0
4.18
4.16
4.14
4.12
4.10
4.08
4.06
4.04
4.02
85°C
25°C
-40°C
-50
-25
0
25
50
75
100
4
4.25 4.5 4.75
5
5.25 5.5 5.75
6
6.25 6.5
Temperature (°C)
V
ADP (V)
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Typical Characteristics – Battery Charger
VEN(H) vs. Supply Voltage
(RSET = 8.06kΩ)
VEN(L) vs. Supply Voltage
(RSET = 8.06kΩ)
1.2
1.1
1
1.1
1
-40°C
-40°C
0.9
0.8
0.7
0.6
0.9
0.8
0.7
25°C
85°C
25°C
85°C
4
4.25 4.5 4.75
5
5.25 5.5 5.75
6
6.25 6.5
4
4.25 4.5
4.75
5
5.25 5.5
5.75
6
6.25 6.5
V
ADP (V)
V
ADP (V)
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Functional Block Diagram
Reverse Blocking
BAT
ADP
-
+
Constant
Current
Charge
Control
ISET
VREF
Over-
Temperature
Protection
STAT
UVLO
EN_BAT
VIN
FB
DH
DL
-
+
LX
Logic
VREF
Input
EN_BUCK
GND
250mA current capability while maintaining over 90%
efficiency at full load. Light load efficiency is maintained
at greater than 80% down to 1mA of load current. A
high-DC gain error amplifier with internal compensation
controls the output. It provides excellent transient
response and load/line regulation.
Functional Description
The AAT2556 is a high performance power system com-
prised of a 500mA lithium-ion/polymer battery charger
and a 250mA step-down converter.
The battery charger is designed for single-cell lithium-ion/
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 the battery
charge state by directly driving one external LED. Internal
device temperature and charging state are fully moni-
tored 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 sys-
tem, and the battery under charge. Other features include
an integrated reverse blocking diode and sense resistor.
Under-Voltage Lockout
The AAT2556 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 charg-
ing 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 appro-
priate mode for the condition of the battery. If the input
voltage of the step-down converter drops below UVLO,
the internal circuit will shut down.
Protection Circuitry
The step-down converter operates with an input voltage
of 2.7V to 5.5V. The switching frequency is 1.5MHz,
minimizing the size of the inductor. Under light load con-
ditions, the device enters power-saving mode; the
switching frequency is reduced, and the converter con-
sumes 30μA of current, making it ideal for battery-oper-
ated applications. The output voltage is programmable
from VIN to as low as 0.6V. Power devices are sized for
Over-Voltage Protection
An over-voltage protection event is defined as a condition
where the voltage on the BAT pin exceeds the over-volt-
age protection threshold (VOVP). If this over-voltage condi-
tion occurs, the charger control circuitry will shut down
the device. The charger will resume normal charging
operation after the over-voltage condition is removed.
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
connected to the BAT pin, the charger checks the condi-
tion 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 pro-
grammed 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 pass MOSFET when the input-output voltage dif-
ferential is at its highest.
Current Limit, Over-Temperature Protection
For overload conditions, the peak input current is limited
at the step-down converter. As load impedance decreas-
es and the output voltage falls closer to zero, more
power is dissipated internally, which causes the internal
die temperature to rise. In this case, the thermal protec-
tion circuit completely disables switching, which protects
the device from damage.
The battery charger has a thermal protection circuit which
will shut down charging functions when the internal die
temperature exceeds the preset thermal limit threshold.
Once the internal die temperature falls below the thermal
limit, normal charging operation will resume.
Pre-conditioning continues until the battery voltage
reaches VMIN. At this point, the charger begins constant-
current charging. The current level for this mode is pro-
grammed using a single resistor from the ISET pin to
ground. Programmed current can be set from a mini-
mum 15mA up to a maximum of 500mA. Constant cur-
rent charging will continue until the battery voltage
reaches the voltage regulation point, VBAT. When the
battery voltage reaches VBAT, the battery charger begins
constant voltage mode. The regulation voltage is factory
programmed to a nominal 4.2V (±0.5%) and will con-
tinue charging until the charging current has reduced to
10% of the programmed current.
Control Loop
The AAT2556 contains a compact, current mode step-
down DC/DC controller. The current through the
P-channel MOSFET (high side) is sensed for current loop
control, as well as short-circuit and overload protection.
A fixed slope compensation signal is added to the sensed
current to maintain stability for duty cycles greater than
50%. The peak current mode loop appears as a voltage-
programmed current source in parallel with the output
capacitor. The output of the voltage error amplifier pro-
grams the current mode loop for the necessary peak
switch current to force a constant output voltage for all
load and line conditions. Internal loop compensation
terminates the transconductance voltage error amplifier
output. The error amplifier reference is fixed at 0.6V.
After the charge cycle is complete, the pass device turns
off and the device automatically goes into a power-sav-
ing sleep mode. During this time, the series pass device
will block current in both directions, preventing the bat-
tery from discharging through the IC.
The battery charger will remain in sleep mode, even if
the charger source is disconnected, until one of the fol-
lowing 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.
Battery Charging Operation
Battery charging commences only after checking several
conditions in order to maintain a safe charging environ-
ment. The input supply (ADP) must be above the mini-
mum operating voltage (UVLO) and the enable pin must
be high (internally pulled down). When the battery is
Preconditioning
Trickle Charge
Constant Current
Charge Phase
Constant Voltage
Charge Phase
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.
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Battery Charging System Operation Flow Chart
Enable
Power On Reset
No
Yes
Power Input
Voltage
VADP > VUVLO
Yes
Fault Conditions
Monitoring
OV, OT
Charge
Control
Shut Down
Yes
No
Preconditioning
Test
Preconditioning
(Trickle Charge)
Yes
V
MIN > VBAT
No
No
Constant
Current Charge
Mode
Recharge Test
Current Phase Test
ADP > VBAT
Yes
Yes
V
RCH > VBAT
V
No
Constant
Voltage Charge
Mode
Voltage Phase Test
IBAT > ITERM
Yes
No
Charge Completed
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Application Information
Normal
ICHARGE (mA)
Set Resistor
Value R2 (k)
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
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 con-
trol 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.
Table 1: RSET Values.
The step-down converter features a soft start that limits
the inrush current and eliminates output voltage over-
shoot during startup. The circuit is designed to increase
the inductor current limit in discrete steps when the
input voltage or enable input is applied. Typical start up
time is 100μs.
1000
100
10
Pulling EN_BUCK to logic low forces the converter in a
low power, non-switching state, and it consumes less
than 1μA of quiescent current. Connecting it to logic high
enables the converter and resumes normal operation.
1
1
10
100
1000
Adapter or USB Power Input
RSET (kΩ)
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
constant current fast charge current for the adapter
input is set by the RSET resistor connected between ISET
and ground. Refer to Table 1 for recommended RSET val-
ues for a desired constant current charge level.
Figure 2: Constant Charging Current
vs. Set Resistor Values.
Charge Status Output
The AAT2556 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 exter-
nal LED. The status pin can indicate several conditions,
as shown in Table 2.
Programming Charge Current
The fast charge constant current charge level is user
programmed with a set resistor placed between the ISET
pin and ground. The accuracy of the fast charge, as well
as the preconditioning trickle charge current, is domi-
nated by the tolerance of the set resistor used. For this
reason, a 1% tolerance metal film resistor is recom-
mended for the set resistor function. Fast charge con-
stant current levels from 15mA to 500mA may be set by
selecting the appropriate resistor value from Table 1.
Event Description
Status
No battery charging activity
Battery charging via adapter or USB port
Charging completed
OFF
ON
OFF
Table 2: LED Status Indicator.
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
The LED should be biased with as little current as neces-
Figure 3 shows the relationship of maximum power dis-
sipation and ambient temperature of the AAT2556.
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.
3000
2500
2000
1500
1000
500
The required ballast resistor values can be estimated
using the following formulas:
0
0
20
40
60
80
100
120
VADP
-
VF(LED)
R1 =
TA (°C)
ILED
Figure 3: Maximum Power Dissipation.
Example:
5.5V - 2.0
V
Next, the power dissipation of the battery charger can
be calculated by the following equation:
R1 =
= 1.75kΩ
2mA
Note: Red LED forward voltage (VF) is typically 2.0V @
2mA.
PD = [(VADP - VBAT) · ICH + (VADP · IOP)]
Where:
Thermal Considerations
PD
= Total Power Dissipation by the Device
= ADP/USB Voltage
= Battery Voltage as Seen at the BAT Pin
= -Constant Charge Current Programmed for the
The AAT2556 is offered in a TDFN33-12 package which
can provide up to 2W of power dissipation when it is
properly bonded to a printed circuit board and has a
maximum thermal resistance of 50°C/W. Many consider-
ations 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 gener-
ating 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 ambi-
ent condition can be estimated by the following discus-
sion.
VADP
VBAT
ICH
Application
IOP
= -Quiescent Current Consumed by the Charger
IC for Normal Operation [0.5mA]
By substitution, we can derive the maximum charge cur-
rent before reaching the thermal limit condition (thermal
cycling). The maximum charge current is the key factor
when designing battery charger applications.
(PD(MAX)
-
VIN
VIN - VBAT
· IOP)
ICH(MAX)
=
First, the maximum power dissipation for a given situa-
tion should be calculated:
(TJ(MAX)
θJA
VIN - VBAT
- TA)
-
VIN · IOP
(TJ(MAX) - TA)
θJA
PD(MAX)
=
ICH(MAX)
=
Where:
In general, the worst condition is the greatest voltage
drop across the IC, when battery voltage is charged up
to the preconditioning voltage threshold. Figure 4 shows
the maximum charge current in different ambient tem-
peratures.
PD(MAX) = Maximum Power Dissipation (W)
JA = Package Thermal Resistance (°C/W)
TJ(MAX) = Maximum Device Junction Temperature (°C)
[135°C]
TA = Ambient Temperature (°C)
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Capacitor Selection
500
400
300
200
100
0
Battery Charger Input Capacitor (C1)
TA = 60°C
In general, it is good design practice to place a decou-
pling 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
TA = 85°C
4.25 4.5 4.75
5
5.25 5.5 5.75
6
6.25 6.5 6.75
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.
VIN (V)
Figure 4: Maximum Charging Current Before
Thermal Cycling Becomes Active.
There are three types of losses associated with the step-
down converter: switching losses, conduction losses, and
quiescent current losses. Conduction losses are associ-
ated with the RDS(ON) characteristics of the power output
switching devices. Switching losses are dominated by the
gate charge of the power output switching devices. At full
load, assuming continuous conduction mode (CCM), a
simplified form of the losses is given by:
Step-Down Converter Input Capacitor (C3)
Select a 4.7μF to 10μF X7R or X5R ceramic capacitor for
the input. To estimate the required input capacitor size,
determine the acceptable input ripple level (VPP) and solve
for CIN. The calculated value varies with input voltage and
is a maximum when VIN is double the output voltage.
VO
VIN
⎛
VO ⎞
VIN ⎠
· 1 -
⎝
IO2 · (RDSON(H) · VO + RDSON(L) · [VIN - VO])
CIN =
PTOTAL
=
⎛ VPP
⎝ IO
⎞
⎠
VIN
- ESR ·FS
+ (tsw · FS · IO + IQ) · VIN
VO
VIN
⎛
VO ⎞
1
· 1 -
⎝
=
for VIN = 2 · VO
IQ is the step-down converter quiescent current. The
term tsw is used to estimate the full load step-down con-
verter switching losses.
VIN ⎠
4
1
CIN(MIN)
=
For the condition where the step-down converter is in
dropout at 100% duty cycle, the total device dissipation
reduces to:
⎛ VPP
⎞
⎠
- ESR · 4 · FS
⎝ IO
Always examine the ceramic capacitor DC voltage coef-
ficient characteristics when selecting the proper value.
For example, the capacitance of a 10μF, 6.3V, X5R
ceramic capacitor with 5.0V DC applied is actually about
6μF.
PTOTAL = IO2 · RDSON(H) + IQ · VIN
Since RDS(ON), quiescent current, and switching losses all
vary with input voltage, the total losses should be inves-
tigated over the complete input voltage range.
The maximum input capacitor RMS current is:
Given the total losses, the maximum junction tempera-
ture can be derived from the JA for the TDFN33-12
package which is 50°C/W.
VO
VIN
⎛
VO ⎞
VIN ⎠
1
2
· 1 -
⎝
=
D · (1 - D) = 0.52 =
TJ(MAX) = PTOTAL · ΘJA + TAMB
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AAT2556
Battery Charger and Step-Down Converter for Portable Applications
The input capacitor RMS ripple current varies with the
input and output voltage and will always be less than or
equal to half of the total DC load current.
be increased to 10μF or more if the battery connection is
made any distance from the charger output. If the
AAT2556 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.
VO
VIN
⎛
VO ⎞
VIN ⎠
IRMS = IO ·
for VIN = 2 · VO
· 1 -
⎝
Step-Down Converter Output Capacitor (C4)
IO
IRMS(MAX)
=
The output capacitor limits the output ripple and pro-
vides holdup during large load transitions. A 4.7μF to
10μF X5R or X7R ceramic capacitor typically provides
sufficient bulk capacitance to stabilize the output during
large load transitions and has the ESR and ESL charac-
teristics necessary for low output ripple. For enhanced
transient response and low temperature operation appli-
cations, a 10μF (X5R, X7R) ceramic capacitor is recom-
mended to stabilize extreme pulsed load conditions.
2
VO
VIN
⎛
⎝
VO
VIN
⎞
⎠
·
1 -
The term
appears in both the input voltage
ripple and input capacitor RMS current equations and is
a maximum when VO is twice VIN. This is why the input
voltage ripple and the input capacitor RMS current ripple
are a maximum at 50% duty cycle.
The input capacitor provides a low impedance loop for the
edges of pulsed current drawn by the step-down con-
verter. Low ESR/ESL X7R and X5R ceramic capacitors are
ideal for this function. To minimize stray inductance, the
capacitor should be placed as closely as possible to the IC.
This keeps the high frequency content of the input current
localized, minimizing EMI and input voltage ripple.
The output voltage droop due to a load transient is dom-
inated by the capacitance of the ceramic output capacitor.
During a step increase in load current, the ceramic output
capacitor alone supplies the load current until the loop
responds. Within two or three switching cycles, the loop
responds and the inductor current increases to match the
load current demand. The relationship of the output volt-
age droop during the three switching cycles to the output
capacitance can be estimated by:
The proper placement of the input capacitor (C3) can be
seen in the evaluation board layout in Figure 6.
A laboratory test set-up typically consists of two long
wires running from the bench power supply to the evalu-
ation board input voltage pins. The inductance of these
wires, along with the low-ESR ceramic input capacitor,
can create a high Q network that may affect converter
performance. This problem often becomes apparent in
the form of excessive ringing in the output voltage dur-
ing load transients. Errors in the loop phase and gain
measurements can also result.
3 · ΔILOAD
=
COUT
V
DROOP · FS
Once the average inductor current increases to the DC
load level, the output voltage recovers. The above equa-
tion establishes a limit on the minimum value for the
output capacitor with respect to load transients.
The internal voltage loop compensation also limits the
minimum output capacitor value to 4.7μF. This is due to
its effect on the loop crossover frequency (bandwidth),
phase margin, and gain margin. Increased output capac-
itance will reduce the crossover frequency with greater
phase margin.
Since the inductance of a short PCB trace feeding the
input voltage is significantly lower than the power leads
from the bench power supply, most applications do not
exhibit this problem.
In applications where the input power source lead induc-
tance cannot be reduced to a level that does not affect
the converter performance, a high ESR tantalum or alu-
minum electrolytic capacitor should be placed in parallel
with the low ESR, ESL bypass ceramic capacitor. This
dampens the high Q network and stabilizes the system.
The maximum output capacitor RMS ripple current is
given by:
1
V
OUT · (VIN(MAX) - VOUT
)
IRMS(MAX)
=
·
L · FS · VIN(MAX)
2 · 3
Battery Charger Output Capacitor (C2)
Dissipation due to the RMS current in the ceramic output
capacitor ESR is typically minimal, resulting in less than
a few degrees rise in hot-spot temperature.
The AAT2556 only requires a 1μF ceramic capacitor on
the BAT pin to maintain circuit stability. This value should
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AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Inductor Selection
Output Voltage (V)
L1 (μH)
1.0
1.2
1.5
1.8
2.5
3.0
3.3
1.5
2.2
2.7
3.0/3.3
3.9/4.2
4.7
The step-down converter uses peak current mode con-
trol with slope compensation to maintain stability for
duty cycles greater than 50%. The output inductor value
must be selected so the inductor current down slope
meets the internal slope compensation requirements.
The internal slope compensation for the AAT2556 is
0.45A/μsec. This equates to a slope compensation that
is 75% of the inductor current down slope for a 1.8V
output and 3.0μH inductor.
5.6
Table 3: Inductor Values.
0.75 ⋅ VO 0.75 ⋅ 1.8V
= 0.45
A
µsec
Adjustable Output Resistor Selection
m =
=
L
3.0µH
Resistors R3 and R4 of Figure 5 program the output to
regulate at a voltage higher than 0.6V. To limit the bias
current required for the external feedback resistor string
while maintaining good noise immunity, the suggested
value for R4 is 59k. Decreased resistor values are nec-
essary to maintain noise immunity on the FB pin, result-
ing in increased quiescent current. Table 4 summarizes
the resistor values for various output voltages.
0.75 ⋅ VO
0.75
⋅
VO
A
µsec
A
L =
=
≈
1.67
⋅ VO
m
0.45A
µsec
µsec
A
= 1.67
⋅ 3.0V = 5.0µH
For most designs, the step-down converter operates
with an inductor value of 1μH to 4.7μH. Table 3 displays
inductor values for the AAT2556 with different output
voltage options.
V
V
3.3V
0.6V
⎛
⎝
⎞
⎛
⎝
⎞
⎠
R3 =
OUT -1 · R4 =
- 1 · 59kΩ = 267kΩ
⎠
REF
With enhanced transient response for extreme pulsed
load application, an external feed-forward capacitor (C5
in Figure 5) can be added.
Manufacturer’s specifications list both the inductor DC
current rating, which is a thermal limitation, and the
peak current rating, which is determined by the satura-
tion characteristics. The inductor should not show any
appreciable saturation under normal load conditions.
Some inductors may meet the peak and average current
ratings yet result in excessive losses due to a high DCR.
Always consider the losses associated with the DCR and
its effect on the total converter efficiency when selecting
an inductor.
R4 = 59k
R3 (k)
R4 = 221k
R3 (k)
VOUT (V)
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.8
1.85
2.0
2.5
3.3
19.6
29.4
39.2
49.9
59.0
68.1
78.7
88.7
118
124
137
187
267
75
113
150
187
221
261
301
332
442
464
523
715
1000
The 3.0μH CDRH2D09 series inductor selected from
Sumida has a 150m DCR and a 470mA DC current rat-
ing. At full load, the inductor DC loss is 9.375mW which
gives a 2.08% loss in efficiency for a 250mA, 1.8V out-
put.
Table 4: Adjustable Resistor Values For
Step-Down Converter.
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AAT2556
Battery Charger and Step-Down Converter for Portable Applications
3. The feedback pin (Pin 1) should be separate from
Printed Circuit Board
any power trace and connect as closely as possible
to the load point. Sensing along a high-current load
trace will degrade DC load regulation. Feedback
resistors should be placed as closely as possible to
the FB pin (Pin 1) to minimize the length of the high
impedance feedback trace. If possible, they should
also be placed away from the LX (switching node)
and inductor to improve noise immunity.
Layout Considerations
For the best results, it is recommended to physically
place the battery pack as close as possible to the
AAT2556 BAT pin. To minimize voltage drops on the PCB,
keep the high current carrying traces adequately wide.
Refer to the AAT2556 evaluation board for a good layout
example (see Figures 6 and 7). The following guidelines
should be used to help ensure a proper layout.
4. The resistance of the trace from the load return to
PGND (Pin 10) and GND (Pin 2) should be kept to a
minimum. This will help to minimize any error in DC
regulation due to differences in the potential of the
internal signal ground and the power ground.
5. A high density, small footprint layout can be achieved
using an inexpensive, miniature, non-shielded, high
DCR inductor.
1. The input capacitors (C1, C3) should connect as
closely as possible to ADP (Pin 9) and VIN (Pin 12).
2. C4 and L1 should be connected as closely as possi-
ble. The connection of L1 to the LX pin should be as
short as possible. Do not make the node small by
using narrow trace. The trace should be kept wide,
direct, and short.
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AAT2556
Battery Charger and Step-Down Converter for Portable Applications
JP4
1
2 3
Buck Input
BAT
ADP
C3
4.7μF
L1
3μH
VIN
R4
R3
VOUT
VOUT
C2
2.2μF
59kΩ
118kΩ
C5
100pF
C4
4.7μF
U1 AAT2556
1
2
3
4
5
6
12
FB
GND
VIN
LX
11
10
9
_
EN BUCK GND
_
EN BAT ADP
8
7
ISET
BAT
GND
C1
10μF
STAT
JP1
0Ω
D1
R2
8.06kΩ
R1
1kΩ
RED LED
1
2
3
1 2
JP3
Enable_Buck
JP2
Enable_Bat
Figure 5: AAT2556 Evaluation Board Schematic.
Figure 6: AAT2556 Evaluation Board
Top Side Layout.
Figure 7: AAT2556 Evaluation Board
Bottom Side Layout.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Component
Part Number
Description
Manufacturer
Battery Charger and Step-Down Converter for Portable
Applications; TDFN33-12 Package
U1
AAT2556IWP-T1
Skyworks
C1
C2
C3, C4
C5
L1
R1
ECJ-1VB0J106M
GRM185B30J225KE25D
GRM188R60J475KE19B
GRM1886R1H101JZ01J
CDRH2D09-3R0
Chip Resistor
Cer 10μF 10V 20% X5R 0603
Cer 2.2μF 6.3V 10% X7R 0603
Cer 4.7μF 6.3V 10% X7R 0603
Cer 100pF 50V 5% R2H 0603
Shielded SMD, 3.0μH, 150m, 3x3x1mm
1K, 5%, 1/4W; 0603
Panasonic - ECG
Murata
Murata
Murata
Sumida
Vishay
R2
R3
Chip Resistor
Chip Resistor
8.06K, 1%, 1/4W; 0603
118K, 1%, 1/4W; 0603
Vishay
Vishay
R4
JP1
Chip Resistor
Chip Resistor
59K, 1%, 1/4W; 0603
0, 5%, 1/4W; 0603
Vishay
Vishay
JP2, JP3, JP4
D1
PRPN401PAEN
CMD15-21SRC/TR8
Connecting Header, 2mm Zip
Red LED; 1206
Sullins Electronics
Chicago Miniature Lamp
Table 5: AAT2556 Evaluation Board Component Listing.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Step-Down Converter Design Example
Specifications
VO = 1.8V @ 250mA, Pulsed Load ILOAD = 200mA
VIN = 2.7V to 4.2V (3.6V nominal)
FS = 1.5MHz
TAMB = 85°C
1.8V Output Inductor
µsec
A
µsec
(use 3.0μH; see Table 3)
⋅ 1.8V = 3µH
A
L1 = 1.67
⋅ VO2 = 1.67
For Sumida inductor CDRH2D09-3R0, 3.0μH, DCR = 150m.
⎛
⎞
⎠
VO
L1 ⋅ FS
VO
VIN
1.8
V
1.8V
4.2V
⎛
⎞
⎠
ΔIL1 =
⋅ 1 -
⎝
=
⋅ 1 -
= 228mA
⎝
3.0µH ⋅ 1.5MHz
ΔIL1
2
IPKL1 = IO +
= 250mA + 114mA = 364mA
2
PL1 = IO ⋅ DCR = 250mA2 ⋅ 150mΩ = 9.375mW
1.8V Output Capacitor
VDROOP = 0.1V
3 · ΔILOAD
VDROOP · FS
3 · 0.2A
COUT
=
=
= 4µF; use 4.7µF
0.1V · 1.5MHz
(VO) · (VIN(MAX) - VO)
L1 · FS · VIN(MAX)
1
1.8V · (4.2V - 1.8V)
1
·
= 66mArms
IRMS
=
·
=
3.0µH · 1.5MHz · 4.2V
2· 3
2· 3
Pesr = esr · IRMS2 = 5mΩ · (66mA)2 = 21.8µW
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Input Capacitor
Input Ripple VPP = 25mV
1
1
CIN =
=
= 1.38µF (use 4.7µF)
⎛ VPP
⎝ IO
⎞
⎛ 25mV
⎝ 0.2A
⎞
⎠
- ESR · 4 · FS
- 5mΩ · 4 · 1.5MHz
⎠
IO
IRMS
=
= 0.1Arms
2
P = esr · IRMS2 = 5mΩ · (0.1A)2 = 0.05mW
AAT2556 Losses
IO2 · (RDSON(H) · VO + RDSON(L) · [VIN -VO])
PTOTAL
=
VIN
+ (tsw · FS · IO + IQ) · VIN
0.22 · (0.59Ω · 1.8V + 0.42Ω · [4.2V - 1.8V])
4.2V
=
+ (5ns · 1.5MHz · 0.2A + 30µA) · 4.2V = 26.14mW
TJ(MAX) = TAMB + ΘJA · PLOSS = 85°C + (50°C/W) · 26.14mW = 86.3°C
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Output Voltage
VOUT (V)
R4 = 59k
R3 (k)
R4 = 221k1
R3 (k)
L1 (μH)
0.62
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.8
1.85
2.0
2.5
3.3
—
—
75
1.5
1.5
1.5
1.5
1.5
1.5
1.5
2.2
2.7
3.0/3.3
3.0/3.3
3.0/3.3
3.9/4.2
5.6
19.6
29.4
39.2
49.9
59.0
68.1
78.7
88.7
118
124
137
187
267
113
150
187
221
261
301
332
442
464
523
715
1000
Table 6: Step-Down Converter Component Values.
Inductance
Max DC
Current (mA)
DCR
(m)
Size (mm)
LxWxH
Manufacturer
Part Number
(μH)
Type
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Sumida
Taiyo Yuden
Taiyo Yuden
Taiyo Yuden
Taiyo Yuden
FDK
CDRH2D09-1R5
CDRH2D09-2R2
CDRH2D09-2R5
CDRH2D09-3R0
CDRH2D09-3R9
CDRH2D09-4R7
CDRH2D09-5R6
CDRH2D11-1R5
CDRH2D11-2R2
CDRH2D11-3R3
CDRH2D11-4R7
NR3010
1.5
2.2
2.5
3
730
600
530
470
450
410
370
900
780
600
500
1200
1100
870
750
1200
1100
1000
900
88
115
135
150
180
230
260
54
78
98
135
80
95
140
190
90
100
120
140
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.2x3.2x1.2
3.2x3.2x1.2
3.2x3.2x1.2
3.2x3.2x1.2
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.0x3.0x1.0
3.2x2.6x0.8
3.2x2.6x0.8
3.2x2.6x0.8
3.2x2.6x0.8
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Chip shielded
Chip shielded
Chip shielded
Chip shielded
3.9
4.7
5.6
1.5
2.2
3.3
4.7
1.5
2.2
3.3
4.7
1.5
2.2
3
NR3010
NR3010
NR3010
MIPWT3226D-1R5
MIPWT3226D-2R2
MIPWT3226D-3R0
MIPWT3226D-4R2
FDK
FDK
FDK
4.2
Table 7: Suggested Inductors and Suppliers.
Manufacturer
Part Number
Value (μF)
Voltage Rating
Temp. Co.
Case Size
Murata
Murata
GRM118R60J475KE19B
GRM188R60J106ME47D
4.7
10
6.3
6.3
X5R
X5R
0603
0603
Table 8: Surface Mount Capacitors.
1. For reduced quiescent current, R4 = 221kW.
2. R4 is opened, R3 is shorted.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
AAT2556IWP-CA-T1
TDFN33-12
SPXYY
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
Adjustable
(0.6V)
A
0.9
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
B
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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DATA SHEET
AAT2556
Battery Charger and Step-Down Converter for Portable Applications
Package Information
TDFN33-121
Index Area
Detail "A"
0.40 0.05
0.1 REF
C0.3
Pin 1 Indicator
(optional)
3.00 0.05
1.70 0.05
Top View
Bottom View
Detail "A"
0.05 0.05
Side View
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.
Copyright © 2012, 2013 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, 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 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 specifications as a result of design defects, errors, or operation of products outside of pub-
lished 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
identification 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.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
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