RT9505
Linear Single Cell Li-Ion Battery Charger IC
General Description
Features
The RT9505 is a fully integrated low cost single-cell LiIon battery charger IC ideal for portable applications. The
RT9505 is capable of being powered up from AC adapter.
The RT9505 enters sleep mode when AC adapter is
removed.
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The RT9505 optimizes the charging task by using a control
algorithm including preconditioning mode, fast charge
mode and constant voltage mode. The charging task is
terminated as the charge current drops below the preset
threshold. 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 RT9505 features 18V maximum rating voltages for
AC adapter. The other features are under voltage
protection, over voltage protection for AC adapter supply
and battery temperature monitoring.
Ordering Information
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18V Maximum Rating for AC Adapter
Internal Integrate 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
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Digital Cameras
Cellular Phones
Personal Data Assistants (PDAs)
MP3 Players
Hand Held PCs
Pin Configurations
RT9505
(TOP VIEW)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
ACIN 1
NC 2
CHG_S 3
PGOOD 4
GND 5
BATT
TS
8 EN
7 NC
ISETA
10
9
GND
11
9
Package Type
QW : WDFN-10L 3x3 (W-Type)
Note :
Richtek products are :
`
RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
`
WDFN-10L 3x3
Suitable for use in SnPb or Pb-free soldering processes.
DS9505-02 April 2011
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
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1
RT9505
Typical Application Circuit
Battery Pack
AC
Adapter
1
BATT
ACIN
10
+
RT9505
1uF
To System
3
To System
4 PGOOD
5, Exposed Pad (11)
TS
CHG_S
GND
EN
ISETA
9
8
Chip Shutdown
Chip Enable
0.1uF to 10uF
6
RSET
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
Charge
Complete
2.8V Precharge
Threshold
Functional Pin Description
Pin No.
Pin Name
Pin Function
ACIN
Wall Adaptor Charge Input Supply.
NC
No Internal Connection.
3
CHG_S
Charge Status Indicator Output (open drain).
4
PGOOD
Power Good Indicator Output (open drain).
5
GND
Ground.
6
ISETA
Wall Adaptor Supply Charge Current Set Point.
8
EN
Charge Enable Input (active low).
9
TS
Temperature Sense Input.
10
BATT
Battery Charge Current Output.
1
2, 7
11 (Exposed Pad) GND
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2
Exposed pad should be soldered to PCB board and connected to GND.
DS9505-02 April 2011
RT9505
Function Block Diagram
ACIN
OVP
Comparator
2.5V
Charge Input Control
GND
SENSE
FET
+
OVP
-
ACIN
PFET
ISETA
BATT
2.5V
V REF
0.5V
Thermal
Sense
115 C
Precharge
Comparator
+
2.5V
-
+
-
0.25V
V/I
Precharge
2.5V
+
-
Recharge
Comparator
+
2.5V
-
V/I
Recharge
0.25V
2.5V
Current
Amplifier
VCC
Precharge
+
Tcrmination
Comparator
0.25V
+
0.9V
-
Voltage
Amplifier
PGOOD
-
Charge Done
Charge
Disable
Logic
Temperature Fault
+
1uA
EN
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Temperature
Sense
CHG_S
TS
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RT9505
Table
RT9505 Flow Chart
Start-Up
Precharge Phase
Fast Charge Phase
Standby/Fault
Recharge Phase
DISABLE
ACIN
Power Up
NO
VACIN > 6.5V or
UVP / OVP
DISABLE MODE
P-MOSFET OFF
IBATT = 0
YES
VEN > 1.4V ?
OVP/UVP MODE
P-MOSFET OFF
IBATT = 0
YES
VACIN < 4.4V?
NO
SLEEP
Start-Up
SLEEP MODE
P-MOSFET OFF
IBATT = 0
YES
VACIN < VBATT ?
NO
1ms Delay
VTS > 2.5V
or
VTS < 0.5V?
RECHARGE
YES
TEMP
FAULT/CHG_S
HIGH
IMPEDANCE
NO
YES
VBATT > 2.8V?
NO
IBATT = 0.1 Charge
Current
/CHG_S Pull Down
YES
IBATT = Charge
Current
/CHG_S Pull Down
YES
STANDBY
PFET OFF
VBATT = 4.2V,
NO
VBATT > 4.1 V?
IBATT = 0
YES
NO
VBATT ~ 4.2V,
IBATT < 0.1 ICHG?
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DS9505-02 April 2011
RT9505
Absolute Maximum Ratings
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(Note 1)
ACIN Input Voltage -------------------------------------------------------------------------------------------------------EN Input Voltage ----------------------------------------------------------------------------------------------------------Output Current ------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
WDFN-10L 3x3 ------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
WDFN-10L 3x3, θJA ------------------------------------------------------------------------------------------------------WDFN-10L 3x3, θJC ------------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Junction Temperature ---------------------------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3)
HBM (Human Body Mode) ---------------------------------------------------------------------------------------------MM (Machine Mode) ------------------------------------------------------------------------------------------------------
Recommended Operating Conditions
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−0.3V to 18V
−0.3V to 6V
1.2A
0.926W
108°C/W
8.2°C/W
260°C
150°C
−65°C to 150°C
2kV
200V
(Note 4)
ACIN 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 = 5V, TA = 27°C, Unless Otherwise specification)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Units
ACIN UVP Rising Threshold Voltage VUV_HIGH
--
4.4
4.5
V
ACIN UVP Hysteresis
VUV_LOW
50
80
120
mV
ACIN Standby Current
ISTBY
VBATT = 4.5V
--
300
500
uA
ACIN Shutdown Current
ISHDN
VEN = HIGH
--
50
100
uA
ACIN UVP Current
IUVP
--
150
250
uA
BATT Sleep Leakage Current
ISLEEP
--
2
5
uA
4.158
4.2
4.242
V
−1
--
+1
%
--
600
--
mΩ
2.45
2.5
2.55
V
100
--
1200
mA
--
500
--
mA
Supply Input
VACIN = 4V, VUSB = 4V,
VBATT = 3V
VACIN = 4V, VUSB = 4V,
VBATT = 4.5V
Voltage Regulation
BATT Regulation Voltage
VREG
IBATT = 60mA
Regulation Voltage Accuracy
ACIN MOSFET
RDS(ON)_ACIN IBATT = 500mA
Current Regulation
ISETA Set Voltage
(Fast Charge Phase)
Full Charge Setting Range
VISETA
ACIN Charge Current accuracy
VBATT = 3.5V
ICHG_AC
ICHG_AC
VBATT = 3.8V,
RISET = 1.5kΩ
To be continued
DS9505-02 April 2011
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RT9505
Parameter
Symbol
Test Conditions
Min
Typ
Max
Units
Precharge
BATT Pre-Charge Rising Threshold
VPRECH
2.6
2.8
3
V
BATT Pre-Charge Threshold
Hysteresis
Pre-Charge Current
ΔV PRECH
50
100
200
mV
IPCHG
VBATT = 2V
8
10
12
%
ΔV RECH_L
VREG − VBATT
60
100
150
mV
VTERM
V BATT = 4.2V
225
250
275
mV
ITERM
V BATT = 4.2V
--
10
--
%
CHG_S Pull Down Voltage
VCHG_S
TBD, ICHG_S = 5mA
--
65
--
mV
PGOOD Pull Down Voltage
VPGOOD
TBD, IPGOOD = 5mA
--
220
--
mV
1.5
--
--
V
--
--
0.4
V
Recharge Threshold
BATT Re-Charge Falling Threshold
Hysteresis
Charge Termination Detection
ISETA Charge Termination Set
Voltage
Termination Current Ratio (default)
Logic Input/Output
EN Threshold
Logic-High Voltage VIH
Logic-Low Voltage
VIL
IEN
VEN = 2V
--
--
2
uA
ITS
VTS = 1.5V
96
102
108
uA
Low Voltage
VTS_LOW
Falling
0.485
0.5
0.515
V
High Voltage
VTS_HIGH
Rising
2.45
2.5
2.55
V
--
125
--
°C
--
6.5
--
V
EN Pin Input Current
Battery Temperature Sense
TS Pin Source Current
TS Pin
Threshold
Protection
Thermal Regulation
OVP SET
Internal Default
Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the
operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended
periods may remain possibility to affect device reliability.
Note 2. θJA is measured in the natural convection at TA = 25°C on a high effective thermal conductivity test board (4 layers, 1S)
of JEDEC 51-7 thermal measurement standard. The case point of θJC is on the expose pad for the package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
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DS9505-02 April 2011
RT9505
Typical Operating Characteristics
ACIN Power On
ACIN Power Off
VACIN
(5V/Div)
VACIN
(5V/Div)
VBATT
(2V/Div)
VBATT
(2V/Div)
CHG_S
(5V/Div)
CHG_S
(5V/Div)
I CHARGE
(0.5A/Div)
I CHARGE
(0.5A/Div)
VBATT = 3.7V
VBATT = 3.7V
Time (250us/Div)
Time (500us/Div)
ACIN OVP
ACIN OVP
VACIN
(10V/Div)
VACIN
(5V/Div)
VBATT
(5V/Div)
VBATT
(5V/Div)
CHG_S
(5V/Div)
CHG_S
(5V/Div)
I CHARGE
(0.5A/Div)
ACIN = 0V to 10V, VBATT = 3.7V
I CHARGE
(1A/Div)
ACIN = 5V to 8V to 5V, VBATT = 3.7V
Time (1ms/Div)
Time (1ms/Div)
Input Voltage Transition
Input Voltage Transition
ACIN Power On
ACIN Power Off
VACIN
(5V/Div)
VACIN
(5V/Div)
CHG_S
(5V/Div)
CHG_S
(5V/Div)
I CHARGE
(1A/Div)
I CHARGE
(1A/Div)
VBATT = 3.7V
VBATT = 3.7V
Time (500us/Div)
DS9505-02 April 2011
Time (500us/Div)
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RT9505
Application Information
Automatically Power Source Selection
resistor or adding two external resistors. (see Figure 2.)
The RT9505 is a battery charger IC which is designed for
Li-ion Battery with 4.2V rated voltage.
The capacitor should be placed close to TS(Pin 9) and
connected to the ground plane. The capacitance value
(0.1uF to 10uF) should be selected according to the quality
of PCB layout. It is recommended to use 10uF if the layout
is poor if prevent noise.
ACIN Mode : When the ACIN input voltage is higher than
the UVP voltage level (4.4V), the RT9505 will turn on ACIN
P-MOSFET.
Sleep Mode : The RT9505 will enter Sleep Mode when
ACIN input voltage are removed. This feature provides low
leakage current from the battery during the absence of
input supply.
V BATT
+
A
ITS
NTC
ACIN Over Voltage Protection
Battery
0.1uF to 10uF
VTS = ITS × RNTC
Turn off when VTS ≥ 2.5V or VTS ≤ 0.5V
Figure 1. Temperature Sensing Configuration
V BATT
A
ITS
Battery Temperature Monitoring
The RT9505 continuously monitors battery temperature
by measuring the voltage between the TS and GND pins.
The RT9505 has an internal current source to provide the
bias for the most common 10kΩ negative-temperature
coefficient thermal resistor (NTC) (see Figure 1). The
RT9505 compares the voltage on the TS pin against the
internal VTS_HIGH and VTS_LOW thresholds to determine
if charging is allowed.
When the temperature outside the VTS_HIGH and
VTS_LOW thresholds is detected, the device will
immediately stop the charge. The RT9505 stops charge
and keep monitoring the battery temperature when the
temperature sense input voltage is back to the threshold
between VTS_HIGH and VTS_LOW, the charger will be
resumed. Charge is resumed when the temperature returns
to the normal range. However the user may modify
thresholds by the negative-temperature coefficient thermal
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TS
Temperature
Sense
+
The ACIN input voltage is monitored by an internal OVP
comparator. The comparator has an accurate reference of
2.5V from the band-gap reference. The OVP threshold is
set by the internal resistive. The protection threshold is
set to 6.5V. When the input voltage exceeds the threshold,
the comparator outputs a logic signal to turn off the power
P-MOSFET to prevent the high input voltage from damaging
the electronics in the handheld system. When the input
over oltage condition is removed (ACIN < 6V), the
comparator re-enables the output by running through the
soft-start.
NTC
TS
Temperature
Sense
R T1
Battery
R T2
0.1uF to 10uF
RT2 × (RT1 + RNTC )
RT1 + RT2 + RNTC
Turn off when VTS ≥ 2.5V or VTS ≤ 0.5V
VTS = ITS
Figure 2. Temperature Sensing Circuit
Fast-Charge Current Setting
The RT9505 offers ISETA pin to determine the ACIN charge
rate from 100mA to 1.2A. The charge current can be
calculated as following equation.
Icharge_ac = K SET
VSET
RSETA
DS9505-02 April 2011
RT9505
The parameter KSET = 300 ; VSET = 2.5V. RSETA is the
resistor connected between the ISETA and GND.
Charge State
ACIN
1200
CHG_S
PGOOD
Charge
ON
ON
Charge done
OFF
ON
Charge Current (mA)
1000
Temperature Regulation and Thermal Protection
800
600
400
200
0
0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
(k)
RRSETA
SETA(kΩ)
Figure 3. ACIN Mode Charge Current Setting
In order to maximize the charge rate, the RT9505 features
a junction temperature regulation loop. If the power
dissipation of the IC results in a junction temperature
greater than the thermal regulation threshold (125°C), the
RT9505 throttles back on the charge current in order to
maintain a junction temperature around the thermal
regulation threshold (125°C). The RT9505 monitors the
junction temperature, TJ, of the die and disconnects the
battery from the input if TJ exceeds 125°C. This operation
continues until junction temperature falls below thermal
regulation threshold (125°C) by the hysteresis level. This
feature prevents the chip from damage.
Pre- Charge Current Setting
During a charge cycle if the battery voltage is below the
VPRECH threshold, the RT9505 applies a pre-charge mode
to the battery. This feature revives deeply discharged cells
and protects battery life. The RT9505 internal determines
the pre-charge rate as 10% of the fast-charge current.
Battery Voltage Regulation
The RT9505 monitors the battery voltage through the BATT
pin. Once the battery voltage level closes to the VREG
threshold, the RT9505 voltage enters constant phase and
the charging current begins to taper down. When battery
voltage is over the VREG threshold, the RT9505 will stop
charge and keep to monitor the battery voltage. However,
when the battery voltage decreases 100mV below the
VREG, it will be recharged to keep the battery voltage.
Charge Status Outputs
The open-drain CHG_S and PGOOD outputs indicate
various charger operations as shown in the following table.
These status pins can be used to drive LEDs or
communicate to the host processor. Note that ON
indicates the open-drain transistor is turned on and LED
is bright.
DS9505-02 April 2011
Selecting the Input and Output Capacitors
In most applications, the most important is the highfrequency decoupling capacitor on the input of the RT9505.
A 1uF ceramic capacitor, placed in close proximity to input
pin and GND pin is recommended. In some applications
depending on the power supply characteristics and cable
length, it may be necessary to add an additional 10uF
ceramic capacitor to the input. The RT9505 requires a
small output capacitor for loop stability. A 1uF ceramic
capacitor placed between the BATT pin and GND is typically
sufficient.
Layout Consideration
The RT9505 is a fully integrated low cost single-cell LiIon battery charger ideal for portable applications. Careful
PCB layout is necessary. For best performance, place all
peripheral components as close to the IC as possible. A
short connection is highly recommended. The following
guidelines should be strictly followed when designing a
PCB layout for the RT9505.
` Input capacitor should be placed close to IC and
connected to ground plane. The trace of input in the
PCB should be placed far away the sensitive devices or
shielded by the ground.
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RT9505
` The GND should be connected to a strong ground plane for heat sinking and noise protection.
` The connection of RSETA should be isolated from other noisy traces. The short wire is recommended to prevent EMI and
noise coupling.
` Output capacitor should be placed close to IC and connected to ground plane to reduce noise coupling.
` The TS's capacitor should be placed close to TS (Pin 9) and connected to ground plane. The capacitance (0.1uF to
10uF) base on PCB layout. When PCB has poor layout, the 10uF is recommended to prevent noise.
The capacitor should be
placed close to IC pin and
connected to ground plane.
C1
C3
ACIN
1
10
BATT
NC
2
9
TS
CHG_S
3
8
EN
PGOOD
4
7
NC
GND
5
9
ISETA
GND
R SETA
GND
The GND should be connected to a
strong ground plane for heat sinking
and noise protection.
Battery
C2
The TS's capacitor should be
placed close to TS(Pin 9) and
connected to ground plane.
The capacitance (0.1uF to
10uF) base on PCB layout.
When PCB has poor layout
the 10uF is recommended to
prevent noise.
The connection of R SETA should be
isolated from other noisy traces.
The short wire is recommended to
prevent EMI and noise coupling.
Figure 4
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DS9505-02 April 2011
RT9505
Outline Dimension
D2
D
L
E
E2
1
e
SEE DETAIL A
2
b
A3
Symbol
2
1
DETAIL A
Pin #1 ID and Tie Bar Mark Options
A
A1
1
Note : The configuration of the Pin #1 identifier is optional,
but must be located within the zone indicated.
Dimensions In Millimeters
Dimensions In Inches
Min
Max
Min
Max
A
0.700
0.800
0.028
0.031
A1
0.000
0.050
0.000
0.002
A3
0.175
0.250
0.007
0.010
b
0.180
0.300
0.007
0.012
D
2.950
3.050
0.116
0.120
D2
2.300
2.650
0.091
0.104
E
2.950
3.050
0.116
0.120
E2
1.500
1.750
0.059
0.069
e
L
0.500
0.350
0.020
0.450
0.014
0.018
W-Type 10L DFN 3x3 Package
Richtek Technology Corporation
Richtek Technology Corporation
Headquarter
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
5F, No. 95, Minchiuan Road, Hsintien City
Hsinchu, Taiwan, R.O.C.
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)86672399 Fax: (8862)86672377
Email: marketing@richtek.com
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit
design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be
guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
DS9505-02 April 2011
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