RT9516

RT9516
Linear Single Cell Li-lon Battery Charger with Single Input
Supply for Portable Applications
General Description
Features
The RT9516 is a fully integrated low cost single-cell
Li-Ion battery charger ideal for portable applications. The
RT9516 is capable of being powered up from AC adapter
and USB (Universal Serial Bus) port inputs. The RT9516
enters sleep mode when supplies are removed. The
RT9516 optimizes the charging task by using a control
algorithm including preconditioning mode, fast charge
mode and constant voltage mode. The charging task will
keep in constant voltage mode to hold the battery in a full
charge condition. The charge current can be programmed
with an external resister. The internal thermal feedback
circuitry regulates the die temperature to optimize the
charge rate for all ambient temperatures. The RT9516
features 28V maximum rating voltages for VIN. The other
features are under voltage protection, over voltage
protection for AC adapter supply.
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The RT9516 is available in WDFN-8L 2x2 tiny package to
achieve best solution for PCB space and total BOM cost
saving considerations.
Ordering Information
RT9516
Package Type
QW : WDFN-8L 2x2 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
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Applications
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Cellular Phones
Digital Cameras
PDAs and Smart Phones
Probable Instruments
Pin Configurations
(TOP VIEW)
VIN
GND
ISET
ABI
1
2
3
4
GND
RT9516 also provide a booting assistant circuit which
detect input source and battery connection condition and
provide an output signal (ABO) for system booting.
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28V Maximum Rating for AC Adapter
Internal Integrated Power MOSFETs
AC Adapter Power Good Status Indicator
Programmed Charging Current
Output for Auto-Booting
Under Voltage Protection
Over Voltage Protection
Thermal Feedback Optimizing Charge Rate
RoHS Compliant and Halogen Free
9
8
7
6
5
BATT
PGOOD
EN
ABO
WDFN-8L 2x2
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Note :
Richtek products are :
`
RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
`
Suitable for use in SnPb or Pb-free soldering processes.
DS9516-01 April 2011
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RT9516
Typical Application Circuit
VIN
(Adapter or USB)
1
CIN
1µF
VIN
BATT
3
2
RSET
COUT
2.2µF
RT9516
6 EN
4 ABI
Chip Enable
8
PGOOD
7
Battery
Pack
To System
ISET
GND
System Supply
ABO 5
Function Block Diagram
BATT
VIN
PGOOD
CC/CV/TR
Loop
Controller
ISET
OVP
VBATT
UVLO
Logic
Controller
ABO
200k
EN
200k
GND
ABI
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DS9516-01 April 2011
RT9516
Flow Chart
Standby State
P-MOSFET = OFF
VIN - VBATT > VOS
YES
NO
VIN < OVP &
EN = H
YES
BATT > 2.5V
NO
Sleep State
P-MOSFET = OFF
YES
Soft-Start
NO
Pre_Charge
ICHG_pre = (1/10) x
ICHG_F
CV State
VBATT = 4.2V
ICHG = 0A
Power Off State
P-MOSFET = OFF
Fast-Charge
ICHG_F = 570mA
RSET = 2.8k
YES
VBATT ≥ 4.2V
NO
Any State or
VIN > OVP or
EN = H
Functional Pin Description
Pin No.
1
2,
9 (Exposed Pad)
Pin Name
VIN
GND
Pin Function
Input Power Source. The VIN can withstand up to 28V input.
Power Ground. The exposed pad must be soldered to a large PCB and connected
to GND for maximum power dissipation.
3
ISET
Charge Current Set Point.
4
ABI
Auto-Booting External Input. ABI is pulled to GND through an internal 200kΩ
resistor.
5
ABO
Auto-Booting Logic Output.
6
EN
Charge Enable (Active Low). With internal 200kΩ pull low resistor.
7
PGOOD
PGOOD pin connect to VIN with 10Ω N-MOSFET as power good condition.
8
BATT
Battery Charge Current Output.
DS9516-01 April 2011
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RT9516
Absolute Maximum Ratings
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(Note 1)
Supply Voltage, VIN ------------------------------------------------------------------------------------------------------Other Pins ------------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
WDFN-8L 2x2 -------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
WDFN-8L 2x2, θJA --------------------------------------------------------------------------------------------------------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 28V
−0.3V to 28V
0.606W
165°C/W
260°C
150°C
−65°C to 150°C
2kV
200V
(Note 4)
Supply Voltage,VIN -------------------------------------------------------------------------------------------------------- 4.5V to 6V
Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C
Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C
Electrical Characteristics
(VIN = 5V, VBATT = 4V, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Offset Voltage (VIN−VBATT) Rising VOS-R
Offset Voltage (VIN− VBATT ) Falling VOS-F
VIN Standby Current
ISTBY
Test Conditions
VBATT = 4.5V
Over Voltage Protection Threshold VOVP
Battery Regulation Voltage
VREG
Regulation
BATT Sleep Leakage Current
ISLEEP
T A = 0 to 85°C
VIN Power MOSFET RDS(ON)
I BATT = 0.5A
Min
Typ
Max
Unit
-10
90
50
150
--
mV
mV
--
300
500
μA
6.5
7
7.5
V
4.158
4.2
4.242
V
--
1
10
μA
--
0.4
0.8
Ω
--
1.4
--
V
ISET Set Voltage (Fast Charge)
VISET
Charge Current Accuracy
ICHG
RSET = 2.8k
524
570
616
mA
BATT Pre-Charge Threshold
VPCHG_BATT BATT Rising
2.3
2.5
2.7
V
Pre-Charge Current
IPCHG
4
10
15
%
EN Threshold
Voltage
Logic-High
VIH
1.5
--
--
V
Logic-Low
VIL
--
--
0.4
V
--
200
--
kΩ
--
115
--
°C
--
65
--
mV
Enable Pull Low Resistor
Thermal Regulation
VPGOOD
5mA
PGOOD Pull Down Voltage
Logic-High
ABI Threshold
VIH
1.5
--
--
V
Voltage
VIL
--
--
0.4
V
--
200
--
kΩ
--
100
--
mV
Logic-Low
ABI Pull Low Resistor
ABO Pull Down Voltage
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4
5mA
DS9516-01 April 2011
RT9516
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 low effective thermal conductivity single layer test board
of JEDEC 51-3 thermal measurement standard.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
DS9516-01 April 2011
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RT9516
Typical Operating Characteristics
BATT Pre-Charge Power On
BATT Fast-Charge Power On
VBATT
(2V/Div)
VBATT
(2V/Div)
EN
(1V/Div)
EN
(1V/Div)
VISET
(100mV/Div)
I IN
(200mA/Div)
VISET
(1V/Div)
VIN = 5V, ICHG = 50mA
I IN
(500mA/Div)
VIN = 5V, ICHG = 500mA
Time (1ms/Div)
Time (1ms/Div)
Power Off from ACIN
Power Off From EN
VIN
(5V/Div)
VBATT
(2V/Div)
EN
(1V/Div)
VBATT
(2V/Div)
VISET
(1V/Div)
VISET
(1V/Div)
I IN
(500mA/Div)
ICHG = 500mA
I IN
(500mA/Div)
VIN = 5V, ICHG = 500mA
Time (1ms/Div)
Time (50μs/Div)
Input Standby Current vs. Input Voltage
Input Shutdown Current vs.Input Voltage
200
Input Shutdown Current (μA)1
Input Standby Current (μA)1
250
200
150
100
50
VBATT = 4.5V, CIN = 1μF
0
4.0
4.3
4.6
4.9
5.2
5.5
5.8
6.1
Input Voltage (V)
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6.4
6.7
7.0
180
160
140
120
VBATT = 3.7V
100
4.0
4.3
4.6
4.9
5.2
5.5
5.8
6.1
6.4
6.7
7.0
Input Voltage (V)
DS9516-01 April 2011
RT9516
Input OVP vs. Temperature
7.1
1000
7.0
Input OVP (V)
Charge Current (mA)
Charge Current vs. RSET
1200
800
600
400
200
6.9
6.8
6.7
6.6
VIN = 5V, VBATT = 3.7V
0
VBATT = 3.7V
6.5
1
2
3
4
5
6
7
8
9
10 11 12 13 14
-40
-20
0
20
40
60
80
100
120
Temperature (°C)
RSET (kΩ)
Battery Regulation Voltage vs. Temperature
Battery Regulation Voltage (V)
4.190
4.185
4.180
4.175
4.170
4.165
4.160
4.155
VIN = 5V
4.150
-40
-20
0
20
40
60
80
100
120
Temperature (°C)
DS9516-01 April 2011
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RT9516
Applications Information
Pre-Charge
Constant
Constant
Mode
Current Mode Voltage Mode
IISET
Programmed
Charge
4.2V
Current
Battery
Regulation
Voltage
threshold
The RT9516 is a fully integrated low cost single-cell
Li-Ion battery charger with a constant current (CC mode)
or a constant voltage (CV mode). The CC mode current is
set with the external resistor RSET and the CV mode voltage
is fixed at 4.2V. If the battery voltage is below a typical
2.5V pre-charge threshold, the RT9516 charges the
battery with a trickle current until the battery voltage rises
above the pre-charge threshold. The RT9516 is capable
of being powered up from AC adapter and USB (Universal
Serial Bus) port inputs.
Recharge
Phase
10%
Programmed
Charge
Current
2.5V
Precharge
Threshold
ACIN Over-Voltage Protection
The input voltage is monitored by the internal comparator.
The OVP threshold is set at 7V (typ.). When the input
voltage exceeds the threshold, the controller 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. However, AC input voltage over 28V
still leads the RT9516 to damage. When the input
overvoltage condition is removed, the controller will enables
the output by running through the soft-start.
Charger Enable Input
EN is an active-low logic input to enable the charger. Drive
the EN pin to low or leave it floating to enable the charger.
This pin has a 200kΩ internal pull down resistor. So when
left floating, the input is equivalent to logic low. Drive this
pin to high to disable the charger.
Battery Charge Profile
Time
Figure 1
a. Battery Pre-Charge Current
During a charge cycle, if the battery voltage is below the
pre-charge threshold, the RT9516 applies a pre-charge
mode to the battery. This feature revives deeply discharged
cells and protects battery life. The internally determined
pre-charge rate of the RT9516 is 10% of the constant
charge current.
b. Battery Fast-Charge Current
The RT9516 offers ISET pin to determine the charge
current. By an external resistor connected between the
ISET and GND. The charge current can be calculated by
the following equation :
V
Icharge = K SET SET
R SET
KSET = 1140; VSET = 1.4(typ.)
Charge Current vs. RSET
The RT9516 charges a Li-ion battery with a constant
current (CC) or a constant voltage (CV). The constant
current of ISET is set with the external resistor RSET and
1000
Charge Current (mA)
the constant voltage is fixed at 4.2V. If the battery voltage
is below a typical 2.5V trickle-charge threshold, the RT9516
charges the battery with a trickle current until the battery
voltage rises above the trickle charge threshold. When
the battery voltage reaches 4.2V, the charger enters a
CV mode and regulates the battery voltage at 4.2V to
fully charge the battery without the risk of over charge.
1200
800
600
400
200
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14
RSET (kΩ)
Figure 2
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DS9516-01 April 2011
RT9516
c. Battery Voltage Regulation (CV Mode)
Temperature Regulation and Thermal Protection
The battery voltage regulation feedback is through the
BATT pin. The RT9516 monitors the battery voltage
between the BATT and GND pins. When battery voltage is
close to battery regulation voltage threshold, the voltage
regulation phase begins and the charging current begins
to taper down. When battery voltage is over battery
regulation voltage threshold and charge mode stops, the
RT9516 still monitors the battery voltage. Charge current
is resumed when the battery voltage under battery
regulation voltage threshold.
In order to maximize charge rate, the RT9516 features a
junction temperature regulation loop. If the power
dissipation of the IC results in a junction temperature that
is greater than the thermal regulation threshold (115°C),
the RT9516 throttles back on the charge current in order
to maintain a junction temperature around the thermal
regulation threshold (115°C). The RT9516 monitors the
junction temperature, TJ, of the die and disconnects the
battery from the input if TJ exceeds 115°C. This operation
continues until junction temperature falls below thermal
regulation threshold (115°C by the hysteresis level. This
feature prevents the maximum power dissipation from
exceeding typical design conditions.
Sleep Mode
The RT9516 enters the sleep mode if both AC and USB
are removed from the input. This feature prevents draining
the battery during the absence of input supply.
Power Good
The open-drain output pin is used to indicate the input
voltage status. The PGOOD output asserts low when
VIN > 4.25V and (VIN − VBATT) > 40mV. These PGOOD pin
can be used to drive LED or communicate to the host
processor. Note that ON indicates the open-drain transistor
is turned on and LED is bright.
Auto-Booting
The RT9516 has an internal “OR” gate that generates an
enable signal for system booting. The battery supplies
power to the “OR” gate, the RT9516 will keep BATT pin
voltage to supply the “OR” gate function when the battery
isn connected at BATT pin. The first input is the AC_PG
and the second input is an external signal (ABI). When
the (VIN − VBATT) > 90mV, the AC_PG signal is high. The
ABI signal is driven by an external system, when external
signal is floating, the ABI has an internal pull low resistor.
VBATT
AC_PG
200k
ABO
ABI
Figure 3
DS9516-01 April 2011
Selecting the Input and Output Capacitors
In most applications, a high-frequency decoupling capacitor
on the input.(1μF ceramic capacitor), placed in close
proximity to the input works well. In some applications
depending on the power supply characteristics and cable
length, it may be necessary to add an additional 10μF
ceramic capacitor to the input. The RT9516 requires a
small output capacitor for loop stability. A 1μF ceramic
capacitor placed between the BATT pin and GND is typically
sufficient.
Thermal Conderations
The maximum power dissipation depends on the thermal
resistance of IC package, PCB layout, the rate of
surroundings airflow and temperature difference between
junction to ambient. The maximum power dissipation can
be calculated by following formula :
PD(MAX) = (TJ(MAX) − TA ) /θJA
Where T J(MAX) is the maximum operation junction
temperature, TA is the ambient temperature and the θJA is
the junction to ambient thermal resistance.
For recommended operating conditions specification of
RT9516, where TJ(MAX) is 125° C and TA is the operated
ambient temperature. The junction to ambient thermal
resistance θJA for WDFN-8L 2x2 package is 165°C/W on
the standard JEDEC 51-3 single-layer thermal test board.
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9
RT9516
The maximum power dissipation at TA = 25°C can be
calculated by following formula :
PD(MAX) = (125°C− 25°C) / (165°C /W) = 0.606W for
WDFN-8L 2x2 package
The maximum power dissipation depends on operating
ambient temperature for fixed T J(MAX) and thermal
resistance θJA. For RT9516 package, the Figure 4 of
derating curves allows the designer to see the effect of
rising ambient temperature on the maximum power
allowed.
0.8
Single Layer PCB
Power Dissipation (W)
0.7
Layout Consideration
The RT9516 is a fully integrated low cost single-cell
Li-Ion 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 RT9516.
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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 from the sensitive devices
or shielded by the ground.
`
The GND and exposed pad should be connected to a
strong ground plane for heat sinking and noise protection.
`
The connection of RSET 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 the IC and
connected to ground plane to reduce noise coupling.
0.6
0.5
WDFN-8L 2x2
0.4
0.3
0.2
0.1
GND
0
25
50
75
100
The capacitor should be
placed close to IC pin
and connected to ground
plane.
125
Ambient Temperature (°C)
Figure 4. Derating Curves for RT9516 Package
CIN
VIN
GND
RSET ISET
ABI
1
2
3
4
GND
0.0
9
8
7
6
5
BATT
PGOOD
EN
ABO
COUT
The connection of resistor should be
The GND should be connected to
isolated from other noisy traces.
The short wire is recommended to a strong ground plane for heat
sinking and noise protection.
prevent EMI and noise coupling.
GND
Figure 5. PCB Layout Guide
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DS9516-01 April 2011
RT9516
Outline Dimension
D2
D
L
E
E2
1
e
SEE DETAIL A
b
2
1
2
1
A
A1
A3
DETAIL A
Pin #1 ID and Tie Bar Mark Options
Note : The configuration of the Pin #1 identifier is optional,
but must be located within the zone indicated.
Symbol
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
0.200
0.300
0.008
0.012
D
1.950
2.050
0.077
0.081
D2
1.000
1.250
0.039
0.049
E
1.950
2.050
0.077
0.081
E2
0.400
0.650
0.016
0.026
e
L
0.500
0.300
0.020
0.400
0.012
0.016
W-Type 8L DFN 2x2 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: [email protected]
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.
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