RT9502
Linear Single Cell Li-Ion Battery Charger IC with
Dual Input Supply
General Description
The RT9502 is a fully integrated low cost single-cell Li-
Ion battery charger IC ideal for portable applications. The
RT9502 is capable of being powered up from AC adapter
and USB (Universal Serial Bus) port inputs. The RT9502
can automatically detect and select the AC adapter and
the USB port as the power source for the charger. The
RT9502 enters sleep mode when both supplies are
removed.
The RT9502 optimizes the charging task by using a control
algorithm including precondition mode, fast charge mode
and constant voltage mode. The charging task is
terminated as the charge current drops below the preset
threshold. The USB charge current can be selected from
preset ratings of 100mA and 500mA, while the AC adapter
charge current can be programmed up to 1A with an
external resister. The internal thermal feedback circuitry
regulates the die temperature to optimize the charge rate
for all ambient temperatures.
The RT9502 features 18V and 7V maximum rating voltages
for AC adapter and USB port inputs respectively. The other
features are under voltage protection, over voltage
protection for AC adapter supply and battery temperature
monitoring.
Features
Automatic Input Supplies Selection
18V Maximum Rating for AC Adapter
Integrated Selectable 100mA and 500mA USB
Charge Current
Internal Integrated P-MOSFETs
AC Adapter Power Good Status Indicator
Charge Status Indicator
Under Voltage Protection
Over Voltage Protection
Automatic Recharge Feature
Battery Temperature Monitoring
Small 10-Lead WDFN Package
Thermal Feedback Optimizing Charge Rate
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Digital Cameras
Cellular Phones
Personal Digital Assistants (PDAs)
MP3 Players
Hand Held PCs
Pin Configurations
(TOP VIEW)
Ordering Information
RT9502
Package Type
QW : WDFN-10L 3x3 (W-Type)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
ACIN
1
USB
2
CHG_S
3
PGOOD
4
GND
5
GND
11
10
9
BATT
TS
8
EN
7
ISETU
ISETA
9
WDFN-10L 3x3
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
DS9502-02 April 2011
www.richtek.com
1
RT9502
Typical Application Circuit
Battery Pack
RT9502
AC
Adapter
USB
1uF
To System
To System
3
EN
ISETU
ISETA
CHG_S
4 PGOOD
5, Exposed Pad(11)
GND
1
1uF
2
USB
TS
9
8
7
6
R
SET
Chip Shutdown
Chip Enable
H : 500mA
L : 100mA
0.1uF to 10uF
ACIN
BATT
10
+
Pre-Charge Phase
Fast Charge
Phase
Constant Voltage
Phase &
Re-Charge Phase
Standby Phase
Programmed
Charge Current
Battery
Voltage
Charging
Current
4.1V Recharge
Threshold
1/10 Programmed
Charge Current
2.8V Precharge
Threshold
Charge
Complete
Functional Pin Description
Pin No.
1
2
3
4
5
6
7
8
9
10
11 (Exposed Pad)
Pin Name
ACIN
USB
CHG_S
PGOOD
GND
ISETA
ISETU
EN
TS
BATT
GND
Pin Function
AC Adaptor Charge Input Supply.
USB Charge Input Supply.
Charge Status Indicator Output (open drain).
Power Good Indicator Output (open drain).
Ground.
Wall Adaptor Supply Charge Current Set Point.
USB Supply Charge Current Set Input (active low).
Charge Enable Input (active low).
Temperature Sense Input.
Battery Charge Current Output.
The exposed pad must be soldered to a large PCB and connected to GND for
maximum power dissipation.
www.richtek.com
2
DS9502-02 April 2011
RT9502
Absolute Maximum Ratings
(Note 1)
−0.3V
to 18V
−0.3V
to 7V
−0.3V
to 6V
1.2A
0.926W
ACIN Input Voltage --------------------------------------------------------------------------------------------------------
USB Input Voltage ---------------------------------------------------------------------------------------------------------
EN Input Voltage -----------------------------------------------------------------------------------------------------------
Output Current -------------------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
WDFN-10L 3x3 -------------------------------------------------------------------------------------------------------------
Package Thermal Resistance (Note 2)
WDFN-10L 3x3,
θ
JA
------------------------------------------------------------------------------------------------------- 108°C/W
WDFN-10L 3x3,
θ
JC
------------------------------------------------------------------------------------------------------- 8.2°C/W
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
Junction Temperature ---------------------------------------------------------------------------------------------------- 150°C
Storage Temperature Range --------------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Mode) ---------------------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ------------------------------------------------------------------------------------------------------ 200V
Recommended Operating Conditions
(Note 4)
ACIN, USB Input Voltage Range --------------------------------------------------------------------------------------- 4.5V to 6V
Junction Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(ACIN = USB = 5V, T
A
= 27°C, Unless Otherwise specification)
Parameter
Supply Input
ACIN/USB UVP Rising Threshold
Voltage
ACIN/USB UVP Hysteresis
ACIN/USB Standby Current
ACIN/USB Shutdown Current
ACIN/USB UVP Current
BATT Sleep Leakage Current
Voltage Regulation
BATT Regulation Voltage
Regulation Voltage Accuracy
ACIN MOSFET
USB MOSFET
Current Regulation
ISETA Set Voltage
(Fast Charge Phase)
Full Charge setting range
DS9502-02 April 2011
Symbol
Test Conditions
Min
Typ
Max
Units
V
UV_HIGH
V
UV_LOW
I
STBY
I
SHDN
I
UVP
I
SLEEP
V
BATT
= 4.5V
V
EN
= High
V
ACIN
= 4V, V
USB
= 4V,
V
BATT
= 3V
V
ACIN
= 4V, V
USB
= 4V
V
BATT
= 4.5V
I
BATT
= 60mA
--
50
--
--
--
--
4.4
80
300
50
150
2
4.5
120
500
100
250
5
V
mV
uA
uA
uA
uA
V
REG
R
DS(ON)_ACI
N
4.158
−1
4.2
--
600
1200
4.242
+1
--
--
V
%
mΩ
mΩ
I
BATT
= 500mA
I
BATT
= 500mA
--
--
R
DS(ON)_USB
V
ISETA
I
CHG_ACIN
V
BATT
= 3.5V
2.42
100
2.5
--
2.55
1200
V
mA
To be continued
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5
Embedded System
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