RT9526A
Linear Single Cell Li-Ion Battery Charger with Input Over
Voltage Protection
General Description
The RT9526A is a fully integrated low cost single cell Li-
ion battery charger ideal for portable applications. The
RT9526A is capable of being powered up from AC adapter
and USB (Universal Serial Bus) port inputs. The RT9526A
enters sleep mode when supplies are removed. The
RT9526A optimizes the charging task by using a control
algorithm including preconditioning mode, fast charge
mode, and constant voltage mode. The charging task will
remain in constant voltage mode to hold the battery in a
full charge condition. The charge current can be
programmed with an external resistor. The internal thermal
feedback circuitry regulates the die temperature to optimize
the charge rate under all ambient temperatures. The
RT9526A features 28V maximum rating voltage for VIN.
The other features are under voltage protection and over
voltage protection for the AC adapter supply.
The RT9526A is available in
WDFN-8L 2x3
package to
achieve best solution for PCB space and total BOM cost
saving considerations.
Features
28V Maximum Rating for AC Adapter
Internal Integrated Power FETs
AC Adapter Power Good Status Indicator
Programmed Charging Current
Charge Status Indicator
Programmed End of Charge Current
Under Voltage Protection
Over Voltage Protection
Thermal Feedback Optimizing Charge Rate
RoHS Compliant and Halogen Free
Applications
Cellular Phones
Digital Cameras
PDAs and Smart Phones
Portable Instruments
Pin Configurations
(TOP VIEW)
GND
VIN
PGB
CHG_SB
ENB
BATT
ISET
IMIN
GND
Ordering Information
RT9526A
Package Type
QW : WDFN-8L 2x3 (W-Type)
Lead Plating System
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.
1
2
3
4
9
8
7
6
5
WDFN-8L 2x3
Marking Information
05 : Product Code
05W
W : Date Code
DS9526A-01 April 2011
www.richtek.com
1
RT9526A
Typical Application Circuit
Adapter or USB
C
IN
R
ISET
R
IMIN
VIN
BATT
C
OUT
RT9526A
ISET
IMIN
GND
ENB
PGB
R2
CHG_SB
V
BATT
R1
V
BATT
Function Pin Description
Pin No.
1
2
3
4
Pin Name
VIN
PGB
CHG_SB
ENB
Pin Function
Supply Voltage Input. VIN can withstand up to 28V input.
Power Good Indicator. This pin connects to VIN with 10SL N-MOSFET as
power good condition.
Charge Status Indicator Output (Open drain). Indicate low when battery is
charging; indicate high when battery charging finished or any fault happened.
Charge Enable (Active Low). Connect this pin with 200kΩ pull low resistor.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
EOC Current Setting Pin.
Charge Current Set Point.
Battery Charge Current Output.
5,
GND
9 (Exposed Pad)
6
IMIN
7
ISET
8
BATT
Function Block Diagram
Switch
Well
VIN
BASE
V
REF
I
BIAS
BATT
Sleep
Mode
Current
Set Block
CC/CV/TR
Multi Loop
Controller
EOC Set
Block
IMIN
CHG_SB
ISET
OVP
UVLO
ENB
200k
GND
PGB
Logic
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2
DS9526A-01 April 2011
RT9526A
Absolute Maximum Ratings
(Note 1)
−0.3V
to 28V
−0.3V
to 7V
−0.3V
to 6V
0.833W
120°C/W
Supply Voltage, VIN ------------------------------------------------------------------------------------------------------
CHG_SB, PGB Pins ------------------------------------------------------------------------------------------------------
Others ------------------------------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
WDFN-8L 2x3 --------------------------------------------------------------------------------------------------------------
Package Thermal Resistance (Note 2)
WDFN-8L 2x3,
θ
JA
---------------------------------------------------------------------------------------------------------
WDFN-8L 2x3,
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
Recommended Operating Conditions
(Note 3)
Junction Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range --------------------------------------------------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(V
IN
= 4.5V, T
A
= 25°C unless otherwise specified)
Parameter
VIN POR Rising Threshold
Voltage
VIN POR Falling Threshold
Voltage
VIN
−
V
BATT
VOS Rising
VIN
−
V
BATT
VOS Falling
VIN Standby Current
BATT Sleep Leakage Current
Battery Regulation Voltage
VIN Power FET On-Resistance
ISET Set Voltage (Fast Charge
Phase)
Charge Current Accuracy
BATT Pre-Charge Threshold
BATT Pre-Charge Threshold
Hysteresis
Pre-Charge Current
ENB Input
Threshold Voltage
Symbol
V
POR_H
V
POR_L
V
OS_H
V
OS_L
Test Conditions
Min
3.4
3.1
--
10
Typ
3.8
3.5
90
50
400
1
4.2
0.6
1.22
500
2.55
100
16.7
--
--
115
7
0.1
200
200
Max
4.2
3.9
150
--
600
5
4.242
--
--
550
2.65
150
21.3
--
0.4
--
7.5
--
--
--
Unit
V
V
mV
mV
μA
μA
V
Ω
V
mA
V
mV
%
V
V
°C
V
V
mV
mV
V
BATT
= 4.5V
I
SLEEP
V
REG
R
DS(ON)
V
ISET
R
ISET
= 24.3kΩ
V
CHG_PRE
ΔV
CHG_PRE
I
CHG_PRE
V
IN
= 4.2V to 24V
I
BATT
= 0.5A
--
--
4.158
--
--
450
2.45
40
12
1.5
--
--
6.7
--
Logic-High V
IH
Logic-Low V
IL
Thermal Regulation
T
REG
VIN Over Voltage Protection
V
OVP
Threshold
VIN OVP Hysteresis
ΔV
OVP
PGB Pull Down Voltage
CHG_SB Pull Down Voltage
5mA
5mA
--
--
To be continued
DS9526A-01 April 2011
www.richtek.com
3
RT9526A
Parameter
EOC Current Setting
EOC Rising Threshold
Symbol
I
IMIN
Test Conditions
R
IMIN
= 243kΩ
R
IREF
= 24.3kΩ
Min
--
337.5
Typ
45
375
Max
--
412.5
Unit
mA
mA
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.
θ
JA
is measured in natural convection at T
A
= 25°C on a low-effective thermal conductivity test board of JEDEC 51-3
thermal measurement standard. The measurement case position of
θ
JC
is on the exposed pad of the packages.
Note 3.
The device is not guaranteed to function outside its operating conditions.
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4
DS9526A-01 April 2011
RT9526A
Typical Operating Characteristics
VOUT Regulation Voltage vs. Input Voltage
4.2420
BATT Sleep Leakage Current vs. Battery Voltage
BATT Sleep Leakage Current (µA)1
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
1
1.5
2
2.5
3
3.5
4
4.5
VOUT Regulation Voltage (V)1
4.2252
4.2084
4.1916
4.1748
4.1580
4.5
5
5.5
6
6.5
7
Input Voltage (V)
Battery Voltage (V)
Charge Current vs. Input Voltage
550
540
530
Pre-Charge Current vs. Input Voltage
95
Pre-Charge Current (mA)
V
BATT
= 3.8V, R
ISET
= 24.3kΩ
91
Charge Current (mA)
520
510
500
490
480
470
460
450
4
4.5
5
5.5
6
6.5
7
87
83
79
V
BATT
= 3.8V, R
ISET
= 24.3kΩ
75
4
4.5
5
5.5
6
6.5
7
Input Voltage (V)
Input Voltage (V)
ISET Voltage vs. Input Voltage
1.25
OVP
ENB : Low
1.24
ISET Voltage (V)
V
IN
(10V/Div)
V
BATT
(2V/Div)
V
CHG_SB
(2V/Div)
I
CHG
(500mA/Div)
7
1.23
1.22
1.21
V
BATT
= 3.8V, R
ISET
= 24.3kΩ
1.20
4
4.5
5
5.5
6
6.5
V
IN
= 0V to 12V, V
BATT
= 3.8V, R
ISET
= 24.3kΩ
Time (500μs/Div)
Input Voltage (V)
DS9526A-01 April 2011
www.richtek.com
5
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