1 www.semtech.com
SC806
Miniature High Current
Lithium-Ion Battery Charger
POWER MANAGEMENT
August 10, 2005
Description
Features
Applications
Typical Application Circuit
Fully integrated charger with FET pass transistor,
reverse-blocking diode, sense resistor and thermal
protection
High Accuracy Charge Current*
Tiny 3mm x 3mm 10 lead MLP package
Programmable precharge, fastcharge and termina-
tion current
Battery voltage controlled to 1% accuracy
Battery Charge Current accurate to 5% at 800mA
Soft-start for step load and adapter plug-in
Up to 1A continuous charge current
Input voltage range from 3V to 6V allows seamless
charging from current limited adapter
0.1µA battery drain current in shutdown and
monitor modes
Over current protection in all charging modes
Automatic loss of battery detection
Adapter Present, Charge Status, and No Battery
output LED drivers
*Patent Pending
Cellular phones
PDAs
Handheld meters
Charging stations
USB chargers
Digital cameras
GPS Handhelds
Programmable current source
The SC806 is a fully integrated, single cell, constant-current (cc)/constant-voltage (cv) Lithium-Ion battery charger
in a tiny 3x3 mm thermally enhanced MLP package. The
SC806 can operate as a stand-alone charger or in conjunction with a Power Management Controller (PMIC).
The SC806 has a pre-charge function for trickle charging
deeply discharged batteries. The fast charge current is
enabled automatically when the battery voltage reaches
the required threshold. When the battery reaches the
constant voltage or CV portion of the charge curve the
SC806 switches to CV regulation mode. In this mode
the output current decays until the termination current is
reached. At this point the SC806 signals the charge cycle
is complete and turns off the output and enters the monitor mode. If the battery voltage drops by 100mV from
the CV voltage a new charge cycle will begin.
The SC806 can also function as a general purpose current source or as a current source for charging NickelCadmium (NiCd) and Nickel-Metal-Hydride (NiMH) batteries.
R2
1k
BA TTERY
D2
LED
R3
3.01k
NOBAT Indic ator
R1
1k
C2
2.2uF
Charging
Indicator
R4
3.01k
SC806 Typical Application Circuit
NTC Voltage
Adapter
Present
Indicator
C1
.1uF
D1
LED
SC806
3
7
2
4
5
10
1
8
9
6
VCC
DIS
CPB
IPRGM
ITERM
CHRGB
VOUT
NOBAT
NTC
GND
CHARGER VIN
查询SC806供应商
2 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
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Absolute Maximum Ratings
Electrical Characteristics
Exceeding the specifications below may result in permanent damage to the device or device malfunction. Operation outside of the parameters
specified in the Electrical Characteristics section is not implied.
Unless otherwise noted: VCC = 4.75V - 5.25V.
*Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCP with thermal vias under the exposed pad per JESD51 standards.
3 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
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Electrical Characteristics (Cont.)
Notes:
* Tied to PCB with 1 Square Inch, 2 Ounce Copper. Tja=41°C/W using JESD 51 Standard.
** Iload=75mA. See typical performance curve for load regulation characteristics.
*** Thermally Limited.
Unless otherwise noted: VCC = 4.75V - 5.25V.
4 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
Pin Configuration Ordering Information
Pin Descriptions
Note:
(1) Only available in tape and reel packaging. A reel contains
3,000 devices.
(2) Available in lead-free packaging only. This product is fully
WEEE and RoHS compliant.
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VOUT
CPB
VCC
IPRGM
ITERM
CHRGB
NTC
NOBAT
DIS
GND
Top View
MLP10: 3x3 10 Lead
1
2
3
4
5
10
9
6
8
7
5 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
Block Diagram
DIS
NTC
GND
CHRGB
10
8
IPRGM
VOUT
1
5
3
9
7
6
ITERM
NOBAT
VOUT
Reference
Voltages
Vout Ref
Fast Charge Ref
Pre-Charge Ref
Fast Charge Ref
Pre-Charge Ref
Control
Over Temp
Under Voltage
Over Voltage
Pre-Charge On
Fast-Charge On
Vout Ref
NTC
Interface
4
VCC
2
CPB
SC806 6V Charger Block Diagram
6 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
General Operation
The SC806 is configured based on the application for
Fast Charge and Termination current. A typical charging
cycle is described below. Details on alternate applications and output programmability are covered in the individual sections.
The charging cycle begins when the adapter is plugged
in. The SC806 performs glitch filtering on the VCC input
and initiates a charge cycle when VCC > UVLO. At this
time, the CHRGB and CPB signals are active low turning
on the LEDs. If the battery voltage is less than 2.8V, the
SC806 will charge the output with the pre-charge current. When the battery voltage exceeds 2.8V, the SC806
enters fast-charge or constant current (CC) mode. When
the battery voltage reaches its final value, the charger
enters the constant voltage (CV) mode. In this mode the
output voltage is held constant and the current decreases until the termination current level is reached.
At this point the charger enters monitor mode and the
CHRGB output is high impedance. The charger output
remains off in monitor mode until Vout drops by 100mV
and a new charge cycle is initiated.
Pre-Charge Mode
Pre-charge mode is automatically enabled whenever the
battery voltage is below 2.8V. It is used to limit the power
dissipation and precondition the battery for fast charging. The pre-charge current value is selected by the resistor on the ITERM pin. The pre-charge current is programmable from 10mA to 125mA. The equation to select the pre-charge current is given by:
100
R
1.5
PCI
TERM
•
=
Fast-Charge Mode (CC)
The fast-charge or CC mode is active when the battery
voltage is above 2.8V and less than the 4.2V CV voltage
of the battery. The fast-charge current can be set to a
maximum of 1.0A and is selected by the program resistor on the IPRGM pin. The voltage on this pin will represent the current through the battery enabling a microprocessor to monitor battery current by sensing the voltage on the IPRGM pin.
The equation to set the fast-
charge current is given by:
1000
PRGM
R
1.5
FCI
•
=
Note that for a given program resistor the current through
the battery in CV mode can be determined by replacing
1.5 with the actual voltage on the IPRGM pin in the above
equation.
Termination Current
Once the battery reaches the program voltage of 4.2V
the device will transition from a constant current source
to a constant voltage source and the current through
the battery begins to decrease while the voltage remains
constant. When the current falls below the programmed
termination current set by the termination resistor on
the ITERM pin, the SC806 will transition the CHRGB pin
from low to high. The equation to set the termination
current is given by:
100
R
1.5
ITERM
TERM
•
=
Monitor Mode
When a charge cycle is completed, the SC806 output
turns off and the device enters monitor mode. If the
voltage of the battery falls below the recharge threshold
of 4.1V the charger will re-initiate a charge cycle. The
maximum current drain of the battery during monitor
mode will be no more than 1µA over temperature
NTC Input/NOBAT output
The SC806 detects the absence of the battery by monitoring the voltage on the NTC pin. When the NTC pin
voltage exceeds 90% of VCC the NOBAT output is driven
high. This function utilizes the standard NTC configuration with the NTC component residing in the battery pack.
When the battery is removed the NTC element in the
resistor divider is missing and the NTC voltage is pulled
up to VCC.
The NOBAT output can be used to signal the system that
the battery has been removed or drive an external LED.
DIS Device Disable Interface
The DIS pin on the SC806 is used to shutdown the SC806
charger. This pin must be pulled low to enable the charger,
high will disable the charger (do not leave floating). The
CPB output indicating the adapter input status is active
regardless of the state of DIS.
7 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
CHRGB LED Flag
The CHRGB LED driver on the SC806 can be used to
drive an LED and/or signal the system processor.
CHRGB=Low (Charging) and CHRGB=High-Z (Charge Complete). The CHRGB output will be high impedance when
the VCC is in a UV condition. The Table below defines the
CHRGB LED output states.
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The CHRGB output signifies the charging status. When
the output current is > Itermination, CHRGB=low. CHRGB
is high impedance when Iout is < Itermination. The
CHRGB output is latched high-Z at the end of the charge
cycle when the output current is less than Itermination.
The CHRGB output will remain high until the battery enters a recharge cycle, or if EN, or VCC are toggled.
.
There are three fault modes detected by the SC806;
(Input under voltage, input over voltage, and Max die temperature or OT). The LED states for these fault modes
are shown below.
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Overcurrent and Max Temperature Protection
Overcurrent protection is inherent in all modes of operation. When the device is in charge-mode the output is
current limited to either the pre-charge current limit value
or the fast charge current limit value depending on the
voltage at the output. Max die temperature protection is
included on the SC806. This feature allows the SC806
to operate with maximum power dissipation by disabling
the output current when the die temperature reaches
OT. The result is that the SC806 will operate as a pulse
charger in extreme power dissipation applications delivering the maximum allowable output current while regulating the internal die temperature to a safe level.
CPB LED Flag
The CPB LED driver on the SC806 is used to indicate
that the adapter voltage is present at the input to the
SC806. The CPB output is an active low output when
the input voltage is greater than 3V. This feature is active regardless of the state of the DIS pin.
Layout Guidelines
The two most critical aspects of the pcb layout are the
power path and thermal layout. The power path starts
at the Adapter + input and runs to the VCC input of the
SC806, then from the Vout pin of the SC806 to the Battery + terminal, and completes with the return trace from
the battery - terminal to the adapter - input. All of these
traces need to be designed to handle the required charging current. The trace from Vout of the SC806 is most
critical and should be made as wide as possible to
minimze IR drops between the regulated voltage at the
SC806 vout pin and the battery terminal. Keep the
Adapter+ to SC806 VCC input trace wide to minimize
voltage drops that will add to the dropout voltage capability of the SC806. The GND pin of the SC806 should
be connected in a kelvin fashion at the Battery terminal
to eliminate voltage drops in the return path reducing
the regulated battery voltage.
The themal performance of the SC806 package requires
a low impedance connection from the heat slug on the
bottom of the package to an external ground plane. This
is best accomplished by using a single large via under
the device connected to a ground plane on the bottom
exposed side of the pcb. The evaluation board uses 1
square inch of copper on the bottom of the pcb and is
capable of 1A charging current.
The input and output bulk decoupling capacitors for the
SC806 should be placed near the external terminals for
the adpater and battery. This short low impedance loop
is for the high current spikes that result from input/output hot-plugging of the charger. To minimize these current spikes should be minimized. A typical application
requires a 0.1µF input/output capacitor. If the distance
from the external terminals to the SC806 is greater than
1”, 0.1µ local decoupling capacitors at the SC806 may
be required.
8 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
Evaluation Board Schematic
Timing Diagram
CHRGB
VCC
NTC
IOUT
VOUT
CPB
DIS
Pre-Charge
UVLO
Soft Start
Pre-Charge
Threshold
CC-mode
IC
Enabled
Fast Charge
CV-mode
High-Z
Low
High-Z
Termination
Current
Re-Charge
Threshold
= VCC
Charge Mode Timing
NoBaT
OVP
Low
Blink
Low,
High-Z
R3
3.01K
CHRG-
1
IPGM
1
D3
LED
SC806
3
7
2
4
5
10
1
8
9
6
VCC
DIS
CPB
IPRGM
ITERM
CHRGB
VOUT
NOBAT
NTC
GND
R11
3.01k
Charging
Indicator
R2
No Pop
R9
3.01k
R6
3.01k
C2
2.2uF
ITRM
1
CPB
1
VOUT+
1
R10
3.01k
R1
3.01k
R12
No Pop
R8 No Pop
VOUT-
1
D2
No Pop
Adapter
Present
Indicator
CHRGB
1
R7 No Pop
R805
No Pop
C1
1uF
D1
LED
R4
No Pop
R806
0
CHRG+
1
NOBAT
1
NTCV
1
DIS
1
R5
1e6
9 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
Typical Characteristics
SC806 Charge Curve
3
3.2
3.4
3.6
3.8
4
4.2
0 0.5 1 1.5 2 2.5 3
Time (Hrs)
Vout (V)
0
0.1
0.2
0.3
0.4
0.5
0.6
Iout (Amps)
Vbatt
ChrgB*
Iout
Fast Char ge Output Curre nt -vs - Resist ance
0
100
200
300
400
500
600
700
800
900
1 870 21 40 2500 3000 3750 5000 7500 15000 30000
Programming Resistor (ohms)
Fast Charge Iout (mA)
Iout_Fast-C harge
Pre-Charge Output Curre nt -vs- Resistance
0
10
20
30
40
50
60
70
80
90
1 870 21 40 2500 3000 3750 5000 7500 15000 30000
Programming Resistor (ohms)
Pre-Charge Iout (mA)
Iout _P r e- C harge
Output Voltage Load Regulation
4.18 1
4.18 2
4.18 3
4.18 4
4.18 5
4.18 6
4.18 7
4.18 8
0.075 0.10.20.30.40.5
Iout (Amps)
Vout (Volts)
Vout CV
Output Voltage Line Regulation
4.18 2
4.1825
4.18 3
4.1835
4.18 4
4.1845
4.18 5
4.1855
4.18 6
4.1865
4.18 7
4.54.75 5 5.25 5.55.75 6
Vcc (Volts)
Vout (Volts)
Vout CV
10 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
Typical Characteristics
Fast Char ge I, Pre -Char ge I V cc < 4.2V
-3 5 .0%
-3 0 .0%
-2 5 .0%
-2 0 .0%
-15. 0%
-10 .0%
-5. 0%
0.0%
5.0%
344.555.5
Input Voltage VCC (volts)
Percen t Erro r in Output Currents
Fast C harge C urre n t E rro r
Pre Charge C u rre n t Error
Ipr ogr am Voltage -vs- Iout
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
15. 00% 20.00% 40.00% 60.00% 80.00% 100.00%
Output Current Percent, CC limit = 100%
Ipog Voltage (Volts)
-10 .00%
-9 .00%
-8 .00%
-7. 00%
-6 .00%
-5. 00%
-4 .00%
-3 .00%
-2 .00%
-1.00%
0.00 %
Iprgm _Volta g e
Iprgm Voltag e Error
Fast Charge Output Curre nt Line Regulation
750
755
760
765
770
775
780
785
790
795
800
3.54 4.14.15 4 . 18 4 . 2
Vout Battery Voltage (Volts)
Iout (mA)
200
300
400
500
600
700
800
900
Iout (mA) Vcc=4.5
Iout _fastQ_vcc=5.0
Iout _fastQ_vcc=5.5
Iout _fastQ_vcc=4.5
Pre-Charge Output Current Line Regulation
51
51.1
51.2
51.3
51.4
51.5
51.6
51.7
51.8
51.9
11.522.52.75
Vout Battery Voltage (Volts)
Iout (mA)
Iout _P ret Q _ vcc=5. 0
Iout _P reQ _ vcc=5. 5
Iout _P reQ _ vcc=4 . 5
Drop-out Voltage -vs- Iout
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
100 500 800
Output Current (mA)
Drop-out Voltage (Volts)
0.4
0.41
0.42
0.43
0.44
0.45
0.46
0.47
0.48
0.49
0.5
Equivolent Drop-Out
Resistance (ohms)
Drop-out_Voltag e
Drop-out Resist ancer
11 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
SC806 State Diagram
Shutdown Mode
Vout/Iout off
CHRGB High Z
Soft Start CC Mode
Start Pre-Charge
OVP> Vin > UVLO
Iout=1500/Rprog
Iout=150/Rterm
Under Voltage will force the
SC806 into Shutdown Mode
from any state.
Monitor Mode
Vout=off
Yes
Dis=Hi
Vout>2.8V
Iout<Iterm
Vout=CV
Start CV Mode
CHRGB Low
CHRGB High Z
Vout< CV-100mV
OV or OT forces the
output off and
CHRGB blinks at 1Hz
Charge resumes when the
Fault is removed
CC=Constant Current
CV=Constant Voltage
Yes
Yes
Yes
CPB=Low
12 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
Outline Drawing - MLPD-10, 3 x 3
Marking Instructions
Top View
Marking for the SC806 MLPD-10 Lead package:
yyww = Date Code (Example: 0012)
806
yyww
13 2004 Semtech Corp. www.semtech.com
SC806
POWER MANAGEMENT
Land Pattern - MLPD-10, 3 x 3
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805)498-2111 FAX (805)498-3804
Contact Information
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