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Miniature High Current Lithium-Ion Battery Charger
POWER MANAGEMENT Description
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.
SC806
Features
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 termination 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 0.1A 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
Applications
Cellular phones PDAs Handheld meters Charging stations USB chargers Digital cameras GPS Handhelds Programmable current source
Typical Application Circuit
SC806 Typical Application Circuit
SC806 CHARGER VIN D2 C1 .1uF LED D1 LED R2 1k R1 1k NOBAT Indicator Adapter Present Indicator 3 10 2 8 7 VCC VOUT CHRGB NTC CPB ITERM NOBAT IPRGM DIS GND 1 9 5 4 6 R4 3.01k R3 3.01k C2 2.2uF NTC Voltage
BATTERY
Charging Indicator
August 10, 2005
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SC806
POWER MANAGEMENT Absolute Maximum Ratings
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.
Parameter VCC, CPB, CHRGB, N TC, DIS to GN D VOUT, N OBAT, IPRGM, ITERM to GN D Power Dissipation MLP (Derate 20mW/C above 85C) Thermal Impedance, Junction to Case Junction Temperature Operating Ambient Temperature Range Peak IR Reflow temperature, soldering 20s-40s Storage Temperature Range VOUT shor t to GN D VOUT Output Current
Symbol
Maximum -0.3 to 7.0 -0.3 to +6.0
Units V V W C/W C C C C A A
Pd JA Tjmax TA T LE A D TSTG
2 50* 150 -40 to +85 260 -65 to 150 Continuous 1
*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.
Electrical Characteristics
Unless otherwise noted: VCC = 4.75V - 5.25V.
Parameter
Symbol
Conditions Min
25oC Typ 5 Max
TA (-40oC to +85C) Units Min 3.15 400 Max 6.3 1200 V A
Input Voltage
VC C ICCDIS Shutdown Mode DIS = 5V Charging Mode, CPB, CHRGB, ITERM, IPRGM = 0 A V C C = 0V
850
Operating Current ICCCHG Battery Leakage Current Regulated Voltage Battery Pre-Charge Current Battery Termination Current IleakBAT VBAT** IPREQ
1.2 0.1 4.2 50
0.8
2.25 1
mA A V
4.16 45
4.24 55
ITERM Resistor R = 3.01k ITERMQ IFastQ1 IFastQ2 Battery Fast-Charge Current Limit
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mA 50 45 91.5 -5 55 111.5 +5 1.0*** mA % A
Battery Fast-Charge Current
IPRGM = 15k IPRGM = 1.87k VBATTERY = 3.8V 2.8V < VBATTERY < VBAT Dropout Voltage = 1V
2
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SC806
POWER MANAGEMENT Electrical Characteristics (Cont.)
Unless otherwise noted: VCC = 4.75V - 5.25V.
Parameter
Symbol
Conditions Min
25oC Typ 1.5 1.5 2.8 2.75 20 50 6.8 6.4 400 2.8 Max
TA (-40oC to +85oC) Min 1.4 1.4 2.65 2.60 Max 1.6 1.6 3.15 3.10
Units
Iprog Regulated Voltage Iterm Regulated Voltage Vin UVLO Rising Threshold Vin UVLO Falling Threshold Vin UVLO Hysteresis Vin OVP Rising Threshold Vin OVP Falling Threshold Vin OVP Hysteresis Vbat Precharge Threshold Vbat Recharge Threshold NTC Thresholds DIS Threshold Over Temperature Shutdown
VIPRGM VITERM VTUVLOR VTUVLOF VTUVLOH VTOVPOR VTOVPOF VTOVPOH VTPREQR VTREQ VTNOBAT VTDIS OT VCBVOL VBAT - VBATTERY No Battery Detect Tested at Vcc=5V VCC=5V Hysteresis = 10C Charging Isnk=2mA Charge Complete, Disable or UV off leakage Charger Present Isnk=2mA UV off leakage NTC=VCC, Isrc=1mA NTC=VCC/2 off leakage 60
V V V V mV
6.3 5.9 150 2.7 140 93 0.4
7.5 7.15 600 2.9
V V mV V mV
100 95 1.0 150 0.2
96 1.25
%Vcc V
C
.5
V
CHRGB LED output ICBOFF VCPVOL ICPOFF NoBat output VNBVOH INBOFF
.1
1
A
0.2 .1 4.8 .1 4.5
.5 1
V A V
CPB LED output
1
A
Notes: * Tied to PCB with 1 Square Inch, 2 Ounce Copper. Tja=41C/W using JESD 51 Standard. ** Iload=75mA. See typical performance curve for load regulation characteristics. *** Thermally Limited.
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SC806
POWER MANAGEMENT Pin Configuration
Top View
VOUT CPB VCC IPRGM ITERM 1 2 3 4 5 10 9 8 7 6 CHRGB NTC NOBAT DIS GND
Ordering Information
Device
(1)
P ackag e MLP-10 Evaluation Board
SC806IMLTRT(2) S C 806E V B
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.
MLP10: 3x3 10 Lead
Pin Descriptions
Pin # 1 2 3 4 5 6 7 8 9 Pin Name VOUT C PB VC C IPRGM ITERM GND DIS NOBAT NTC Pin Function Charger output, connect to battery. Output status indicator for the adapter present. This output is active low when the VCC input voltage is above the UVLO threshold. Supply pin, connect to adaptor power. Charger current limit program pin. Requires a resistor to ground to program fast-charge current. Selection for current termination and pre-charge current. Requires a resistor to ground to program pre-charge and termination current. Ground. Device disable/enable pin. This pin is active low to enable the SC806, a high level disables operation. Output status indicator for 'No Battery' condition. Output is active high when the battery is removed. Output is high impedance when the battery is present. This pin is used to detect the NTC element inside the battery pack by detecting a voltage within 95% of VCC. Connect to resistor pullup to VCC and NTC to ground. This pin only controls the NOBAT output and does not effect the charger output. Output status indicator. Active low output indicates charger is delivering current to the battery. CHRGB output goes high impedance when the output current falls below the termination current setting and the output is turned off. Connect cathode of the 'charging' LED this pin to indicate charge in progress.
10
CHRGB
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SC806
POWER MANAGEMENT Block Diagram
VCC 3
Reference Voltages GND 6 CPB 2 NOBAT 8 Control
Vout Ref Fast Charge Ref Pre-Charge Ref
Pre-Charge On Fast-Charge On Over Temp Under Voltage Over Voltage VOUT 1
DIS 7 NTC 9 CHRGB 10
NTC Interface
IPRGM 4
Fast Charge Ref VOUT Vout Ref Pre-Charge Ref ITERM 5
SC806 6V Charger Block Diagram
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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:
1.5 PCI = R TERM * 100
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:
1.5 * 100 ITERM = R 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 1A 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.
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 fastcharge current is given by:
1.5 * 1000 FCI = R PRGM
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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.
LED CHRGB Low Iout > term High-Z Iout < term Blinking OV or OT Fault
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 0.1F input/output capacitor. If the distance from the external terminals to the SC806 is greater than 1", 0.1 local decoupling capacitors at the SC806 may be required.
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.
Fault VCC UVLO VCC OVP Tj > 150oC CHR GB High-Z Blinking B l i n ki n g
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.
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SC806
POWER MANAGEMENT Evaluation Board Schematic
CHRG+ 1
R806 0
R805 No Pop
R4 No Pop CHRGB CPB 1 D1 C1 1uF LED D2 No Pop R12 R1 3.01k Charging Indicator No Pop R2 No Pop R3 3.01K NOBAT Adapter Present Indicator 1 R8 No Pop IPGM 1 1 ITRM NTCV 1 1 3 10 2 8 7 DIS 1 SC806 VCC VOUT CHRGB NTC CPB ITERM NOBAT IPRGM DIS GND 1 9 5 4 6 VOUT+ 1
D3 LED
R7 No Pop
C2 2.2uF
R6 3.01k CHRG1
R5 1e6
R9 3.01k
R10 3.01k
R11 3.01k
VOUT1
Timing Diagram
Charge Mode Timing
UVLO VCC Pre-Charge Threshold Fast Charge Soft Start Pre-Charge CC-mode CPB CV-mode Blink Low, High-Z Re-Charge Threshold OVP
VOUT
IOUT
Termination Current
CHRGB
High-Z
Low
High-Z
Low
DIS
IC Enabled
NTC
= VCC
NoBaT
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SC806
POWER MANAGEMENT Typical Characteristics
SC806 Charge Curve 0.6 4.2 4 Vout (V) 3.8 3.6 3.4 3.2 3 0 0.5 1 1.5 Tim e (Hrs) 2 2.5 3
V bat t C hr * gB I out
0.5 Iout (Amps) 0.4 0.3 0.2 0.1 0
Fast Charge Output Current -vs- Resistance
900 800 700 600 500 400 300 90 80 70
Pre-Charge Output Current -vs- Resistance
Fast Charge Iout (mA)
Pre-Charge Iout (mA)
60 50 40 30
I _Fast C har out ge
200 100 0 1870 2140 2500 3000 3750 5000 7500 15000 30000
I _Pr C har out ege
20 10 0 1870 2140 2500 3000 3750 5000 7500 15000 30000
Programm ing Resistor (ohm s)
Programm ing Resistor (ohm s)
Output Voltage Load Regulation
4. 188 4. 187 4. 1865 4. 187
Output Voltage Line Regulation
V out C V
4. 186
4. 186 4. 1855
V out C V
Vout (Volts)
Vout (Volts)
0. 075 0. 1 0. 2 0. 3 0. 4 0. 5
4. 185
4. 185 4. 1845 4. 184 4. 1835 4. 183
4. 184
4. 183
4. 182 4. 1825 4. 181 4. 182 4. 5 4. 75 5 5. 25 5. 5 5. 75 6
Iout (Am ps)
Vcc (Volts)
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SC806
POWER MANAGEMENT Typical Characteristics
Fast Charge I, Pre-Charge I Vcc < 4.2V
- 0% 35. 18 . 16 . Fast C har C ur entEr or ge r r - 0% 25. 14 .
Iprogram Voltage -vs- Iout
0. 00% -. 1 00% - 00% 2. - 00% 3. 12 . - 00% 4. 1 - 00% 5. 0. 8 - 00% 6. 0. 6 I gm _V olage pr t 0. 4 0. 2 0 I gm V olage Er or pr t r - 00% 7. - 00% 8. - 00% 9. - 0. 1 00% 1 00% 5. 20. 00% 40. 00% 60. 00% 80. 00% 1 00% 00.
Percent Error in Output Currents
- 0% 30.
- 0% 20.
- 5. 1 0%
- 0. 1 0%
- 0% 5.
0. 0%
5. 0% 3 4 4. 5 5 5. 5
Ipog Voltage (Volts)
Pr C har C ur ent Er or e ge r r
Input Voltage VCC (volts) Fast Charge Output Current Line Regulation
800 795 800 790 51 7 . 900 51 9 . 51 8 .
Output Current Percent, CC lim it = 100% Pre-Charge Output Current Line Regulation
Iout (mA) Vcc=4.5
785
700
51 6 .
Iout (mA)
600 775 500 770 765 I _f Q _vcc=5. out ast 0 760 755 750 3. 5 4 4. 1 4.5 1 4.8 1 4. 2 I _f Q _vcc=5. out ast 5 I _f Q _vcc=4. out ast 5 300 400
Iout (mA)
780
51 5 . I _Pr Q _vcc=5. out et 0 51 4 . 51 3 . 51 2 . 51 1 . I _Pr _vcc=5. out eQ 5 I _Pr _vcc=4. out eQ 5
200
51 1 15 . 2 2. 5 2. 75
Vout Battery Voltage (Volts) Drop-out Voltage -vs- Iout
0. 4 0. 5 0. 49 0. 48
Vout Battery Voltage (Volts)
0. 35 D r out ol age op- _V t D r out R esi ancer opst 0. 25
Drop-out Voltage (Volts)
0. 47 0. 46 0. 45 0. 44 0. 43
0. 2
0.5 1
0. 1 0. 42 0. 05 0. 41 0. 4 1 00 500 800
0
Output Current (m A)
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Equivolent Drop-Out Resistance (ohms)
0. 3
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SC806
POWER MANAGEMENT SC806 State Diagram
Under Voltage will force the SC806 into Shutdown Mode from any state.
OVP> Vin > UVLO
Shutdown Mode Vout/Iout off CHRGB High Z
CPB=Low
Dis=Hi CHRGB Low Start Pre-Charge
Yes CC=Constant Current CV=Constant Voltage
Yes Vout>2.8V Soft Start CC Mode Iout=150/Rterm Iout=1500/Rprog
Vout=CV Yes Start CV Mode
IoutVout< CV-100mV
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SC806
POWER MANAGEMENT Outline Drawing - MLPD-10, 3 x 3
Marking Instructions
806 yyww
Top View Marking for the SC806 MLPD-10 Lead package: yyww = Date Code (Example: 0012)
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SC806
POWER MANAGEMENT Land Pattern - MLPD-10, 3 x 3
Contact Information
Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804
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