LINER LTC4066

LTC4066/LTC4066-1
USB Power Controller and
Li-Ion Linear Charger with
Low Loss Ideal Diode
DESCRIPTION
FEATURES
n
n
n
n
n
n
n
n
n
n
n
n
n
Seamless Transition Between Input Power Sources:
Li-Ion Battery, USB and 5V Wall Adapter
Low Loss (50mΩ) Ideal Diode Path from BAT to OUT
Programmable Charge Current Detection (CHRG)
Load Dependent Charging Guarantees USB Input
Current Compliance
Analog Gas Gauge Function
Charges Single Cell Li-Ion Batteries Directly from
USB Port
Constant-Current/Constant-Voltage Operation with
Thermal Feedback to Maximize Charging Rate
Without Risk of Overheating*
Selectable 100% or 20% Current Limit
(e.g., 500mA/100mA)
Termination Timer Adapts to Actual Charge Current
Preset 4.2V Charge Voltage with 0.8% Accuracy
(4.1V for LTC4066-1)
NTC Thermistor Input for Temperature Qualified
Charging
Thin Profile (0.75mm) 24-Lead 4mm × 4mm
QFN Package
Ultrathin Profile (0.55mm) 24-Lead 4mm × 4mm
UTQFN Package (LTC4066 Only)
n
n
The LTC4066/LTC4066-1 include a standalone constantcurrent/constant-voltage linear charger for single cell
Li-ion batteries. The float voltage applied to the battery
is held to a tight 0.8% tolerance, and charge current
is programmable using an external resistor to ground.
A programmable end-of-charge status output (CHRG)
indicates full charge. BAT pin charge and discharge currents can be monitored via an analog output (ISTAT). Total
charge time is programmable by an external capacitor to
ground. When the battery drops 100mV below the float
voltage, automatic recharging of the battery occurs. Also
featured is an NTC thermistor input used to monitor battery temperature while charging.
The LTC4066/LTC4066-1 are available in a 24-pin thin
profile (0.75mm) 4mm × 4mm QFN package. The LTC4066
is also available in a 24-pin ultrathin profile (0.55mm)
4mm × 4mm UTQFN package.
APPLICATIONS
n
The LTC®4066/LTC4066-1 are USB power managers and
Li-Ion battery chargers designed to work in portable
battery-powered applications. The parts control the total
current used by the USB peripheral for operation and
battery charging. The total input current can be limited
to 100mA, 500mA or “unlimited” (i.e., above 2A). Battery
charge current is automatically reduced such that the sum
of the load current and the charge current does not exceed
the programmed input current limit.
Portable USB Devices
GPS, Cameras, Broadband Wireless Modems
Mulitple Input Chargers
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. PowerPath
is a trademark of Linear Technology Corporation. All other trademarks are the property of their
respective owners. *Protected by U.S. Patents including 6522118.
TYPICAL APPLICATION
4.7μF
IN
OUT
VNTC
BAT
NTC
WALL
SHDN
SUSPEND USB POWER
SUSP
500mA/100mA SELECT
HPWR
510Ω
CHRG
LTC4066
ACPR
TO ADC FOR
GAS GAUGE
ISTAT
CLPROG
400
ILOAD
300
200
100k
2k
IBAT
CHARGING
0
GND
–100
0.1μF
IIN
500
100
POL
CLDIS
TIMER PROG
INPUT CURRENT
LIMIT DISABLE
510Ω
+
TO LDOs,
REGs, ETC
4.7μF
CURRENT (mA)
5V (NOM)
FROM USB
CABLE VBUS
600
2k
4066 TA01
0
100
200
300
400
ILOAD (mA)
500
600
IBAT
(IDEAL DIODE)
4066 TA02
4066fc
1
LTC4066/LTC4066-1
ABSOLUTE MAXIMUM RATINGS
(Notes 1 to 6)
Terminal Voltage
t < 1ms and Duty Cycle < 1%
IN, OUT ................................................... –0.3V to 7V
Steady State
IN, OUT, BAT ........................................... –0.3V to 6V
NTC, VNTC, TIMER, PROG,
CLPROG, ISTAT ....................... –0.3V to (VCC + 0.3V)
CHRG, HPWR, SUSP, SHDN,
WALL, ACPR, POL, CLDIS ...................... –0.3V to 6V
Pin Current (DC)
IN (Note 7) .......................................................... 2.7A
OUT, BAT (Note 7) .................................................. 5A
Operating Temperature Range................. –40°C to 85°C
Maximum Operating Junction Temperature ......... 125°C
Storage Temperature Range.................. –65°C to 125°C
PIN CONFIGURATION
24 23 22 21 20 19
POL
WALL
TIMER
CLPROG
PROG
POL
ISTAT
TOP VIEW
WALL
TIMER
CLPROG
PROG
ISTAT
TOP VIEW
24 23 22 21 20 19
OUT 1
18 CHRG
OUT 1
18 CHRG
BAT 2
17 ACPR
BAT 2
17 ACPR
OUT 3
16 GND
OUT 3
15 VNTC
BAT 4
14 NTC
BAT 5
8
9 10 11 12
SHDN
7
SUSP
IN
UF PACKAGE
24-LEAD (4mm s 4mm) PLASTIC QFN
13 HPWR
CLDIS
NC
OUT
SHDN
9 10 11 12
SUSP
8
CLDIS
7
14 NTC
NC 6
13 HPWR
IN
NC 6
15 VNTC
OUT
BAT 5
16 GND
25
NC
25
BAT 4
PF PACKAGE
24-LEAD (4mm s 4mm) PLASTIC UTQFN
TJMAX = 125°C, θJA = 37°C/W
EXPOSED PAD (PIN #) IS GND, MUST BE SOLDERED TO PCB
TJMAX = 125°C, θJA = 37°C/W
EXPOSED PAD (PIN #) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC4066EUF#PBF
LTC4066EUF#TRPBF
4066
24-Lead (4mm × 4mm) Plastic QFN
–40°C to 85°C
LTC4066EUF-1#PBF
LTC4066EUF-1#TRPBF
40661
24-Lead (4mm × 4mm) Plastic QFN
–40°C to 85°C
LTC4066EPF#PBF
LTC4066EPF#TRPBF
4066T
24-Lead (4mm × 4mm) Plastic UTQFN
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
4066fc
2
LTC4066/LTC4066-1
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 5V, VBAT = 3.7V, HPWR = 5V, WALL = 0V, RPROG = 100k,
RCLPROG = RISTAT = 2k, unless otherwise noted.
SYMBOL
VIN
VBAT
IIN
PARAMETER
Input Supply Voltage
Input Voltage
Input Supply Current
IOUT
BAT
Output Supply Current
Battery Drain Current
IIN(MAX)
VUVLO
Maximum Input Current Limit
Input or Output Undervoltage Lockout
ΔVUVLO
Input or Output Undervoltage Lockout
Current Limit
Current Limit
ILIM
RON
ON Resistance VIN to VOUT
VCLPROG
CLPROG Pin Voltage
Soft-Start Inrush Current
Automatic Current Limit Enable Threshold
Voltage
Battery Charger
Regulated Output Voltage
VFLOAT
ISS
VALEN
IBAT
Current Mode Charge Current
IBAT(MAX)
VPROG
Maximum Charge Current
PROG Pin Voltage
kISTAT
Ratio of IBAT (Charging) to ISTAT
Pin Current
VEOC
ITRIKL
VTRIKL
VCEN
End-of-Charge ISTAT Pin Voltage
Trickle Charge Current
Trickle Charge Threshold Voltage
Charger Enable Threshold Voltage
VRECHRG
tTIMER
Recharge Battery Threshold Voltage
TIMER Accuracy
Recharge Time
Low-Battery Trickle Charge Time
CONDITIONS
IN and OUT
BAT
IBAT = IISTAT = 0 (Note 8)
Suspend Mode; SUSP = 2V
Suspend Mode; SUSP = 2V, Wall = 2V, VOUT = 4.8V
Shutdown; SHDN = 2V
VOUT = 5V, VIN = 0V, VBAT = 4.3V, TIMER = 0V
VBAT = 4.3V, Charging Stopped
Suspend Mode; SUSP = 2V
Shutdown; SHDN = 2V
VIN = 0V, BAT Powers OUT, No Load
(Note 9)
VIN Powers Part, Rising Threshold
VOUT Powers Part, Rising Threshold
VIN Rising – VIN Falling or
VOUT Rising – VOUT Falling
RCLPROG = 2k, HPWR = 5V
RCLPROG = 2k, HPWR = 0V
HPWR = 5V, 400mA Load
HPWR = 0V, 80mA Load
RCLPROG = 2k
RCLPROG = 1k
IN or OUT
(VIN – VOUT) VIN Rising
(VIN – VOUT) VIN Falling
(0°C to 85°C), IBAT = 2mA
IBAT = 2mA
(0°C to 85°C), IBAT = 2mA (LTC4066-1)
IBAT = 2mA (LTC4066-1)
RPROG = 100k, No Load
RPROG = 50k, No Load
(Note 9)
RPROG = 100k
RPROG = 50k
IBAT = 50mA
IBAT = 100mA
IBAT = 500mA
IBAT = 1000mA
VBAT = VFLOAT (4.2V, 4.1V for LTC4066-1)
VBAT = 2V, RPROG = 100k
l
TYP
l
l
l
l
l
l
l
l
l
l
l
l
1.9
3.6
3.6
l
l
475
90
l
0.980
0.980
25
–85
l
l
l
l
l
l
l
l
l
l
l
l
(VOUT – VBAT) High to Low, VBAT = 4V
(VOUT – VBAT) Low to High, VBAT = 4V
VFLOAT – VRECHRG
VBAT = 4.2V (4.1V for LTC4066-1)
Percent of Total Charge Time
Percent of Total Charge Time, VBAT < 2.8V
MIN
4.35
l
4.165
4.158
4.066
4.059
460
920
0.980
0.980
875
900
925
950
94
35
2.8
60
–10
0.5
50
50
10
400
15
15
2.5
55
2.6
3.8
3.8
125
500
100
0.16
0.16
1.000
1.000
10
50
–60
4.200
4.200
4.100
4.100
500
1000
1.5
1.000
1.000
1000
1000
1000
1000
100
50
2.9
60
90
100
50
25
MAX
5.5
4.3
1.2
100
100
20
800
27
27
5
100
4
4
525
110
1.020
1.020
75
–25
4.235
4.242
4.134
4.141
540
1080
1.020
1.020
1125
1100
1075
1050
106
60
3
130
10
UNITS
V
V
mA
μA
μA
μA
μA
μA
μA
μA
μA
A
V
V
mV
mA
mA
Ω
Ω
V
V
mA/μs
mV
mV
V
V
V
V
mA
mA
A
V
V
mA/mA
mA/mA
mA/mA
mA/mA
mV
mA
V
mV
mV
mV
%
%
%
4066fc
3
LTC4066/LTC4066-1
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 5V, VBAT = 3.7V, HPWR = 5V, WALL = 0V, RPROG = 100k,
RCLPROG = RISTAT = 2k, unless otherwise noted.
SYMBOL
TLIM
PARAMETER
Junction Temperature in Constant
Temperature Mode
Ideal Diode
Incremental Resistance, VON Regulation
RFWD
On-Resistance VBAT to VOUT
RDIO(ON)
Voltage Forward Drop (VBAT – VOUT)
VFWD
kDIO,ISTAT
VOFF
IFWD
ID(MAX)
Logic
VOL
VIH
VIL
IPULLDN
VCHG,SD
Ratio of IBAT (Discharging Through Ideal
Diode) to ISTAT Pin Current
Diode Disable Battery Voltage
Load Current Limit for VON Regulation
Diode Current Limit
Output Low Voltage (CHRG, ACPR, POL)
Enable Input High Voltage
Enable Input Low Voltage
Logic Input Pull-Down Current
Charger Shutdown Threshold Voltage on
TIMER
Charger Shutdown Pull-Up Current on
ICHG,SD
TIMER
Wall Input Threshold Voltage
VWALL
VWALL,HYS Wall Input Hysteresis
Wall Input Leakage Current
IWALL
NTC
VNTC Pin Current
IVNTC
VNTC Bias Voltage
VVNTC
NTC Input Leakage Current
INTC
Cold Temperature Fault Threshold Voltage
VCOLD
VHOT
Hot Temperature Fault Threshold Voltage
VDIS
NTC Disable Voltage
CONDITIONS
MIN
IBAT = 500mA
IBAT = 3A
IBAT = 5mA
IBAT = 200mA
IBAT = 2A
IBAT = 5mA
IBAT = 20mA
l
10
850
850
VBAT = 3.5V
3.8
ISINK = 5mA
SUSP, SHDN, HPWR, CLDIS Pin
SUSP, SHDN, HPWR, CLDIS Pin
SUSP, SHDN, HPWR, CLDIS
l
l
TYP
105
27
45
30
47
95
1000
1000
2.8
2.5
5.2
0.1
1150
1150
0.25
0.4
2
0.15
VTIMER = 0V
l
2
4
VWALL Rising Threshold
VWALL Rising – VWALL Falling Threshold
VWALL = 1V
l
1.200
1.225
35
0
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: VCC is the greater of VIN, VOUT or VBAT .
Note 3: Pins 1, 3 and 8 (OUT) should be tied together with a low
impedance to ensure that the difference between the three pins does not
exceed 50mV. Pins 2, 4 and 5 (BAT) should be tied together with a low
impedance to ensure that the difference between the three pins does not
exceed 50mV.
Note 4: All voltage values are with respect to GND.
Note 5: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
50
1.2
l
l
VVNTC = 2.5V
IVNTC = 500μA
VNTC = 1V
Rising Threshold
Hysteresis
Falling Threshold
Hysteresis
NTC Input Voltage to GND (Falling)
Hysteresis
MAX
l
l
0.4
UNITS
°C
mΩ
mΩ
mV
mV
mV
mA/mA
mA/mA
V
A
A
V
V
V
μA
V
μA
±50
V
mV
nA
2.5
3.5
4.85
0
±1
0.74 • VVNTC
0.02 • VVNTC
0.29 • VVNTC
0.01 • VVNTC
75
100
125
35
mA
V
μA
V
V
V
V
mV
mV
1.5
4.4
1.250
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 6: The LTC4066/LTC4066-1 are guaranteed to meet performance
specifications from 0°C to 70°C. Specifications over the –40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 7: Guaranteed by long term current density limitations.
Note 8: Total input current is equal to this specification plus 1.003 × IBAT
where IBAT is the charge current.
Note 9: Accuracy of programmed current may degrade for currents greater
than 1.5A.
4066fc
4
LTC4066/LTC4066-1
TYPICAL PERFORMANCE CHARACTERISTICS
Input Supply Current
vs Temperature
800
700
VIN = 5V
VBAT = 4.2V
RPROG = 100k
RCLPROG = 2k
SUSP = 5V
50
600
40
IIN (μA)
IIN (μA)
70
60
VIN = 5V
VBAT = 4.2V
RPROG = 100k
RCLPROG = 2k
500
400
60
30
20
300
VIN = 0V
VBAT = 4.2V
50
IBAT (μA)
900
Battery Drain Current vs
Temperature (BAT Powers OUT,
No Load)
Input Supply Current vs
Temperature (Suspend Mode)
40
30
20
200
10
10
100
0
–50
–25
0
25
50
TEMPERATURE (°C)
75
0
–50
100
–25
0
25
50
TEMPERATURE (°C)
75
0
–50
100
Input Current Limit vs
Temperature, HPWP = 5V
75
110
VIN = 5V
VBAT = 3.7V
RPROG = 100k
515 R
CLPROG = 2k
CLPROG Pin Voltage vs
Temperature
1200
VIN = 5V
VBAT = 3.7V
RPROG = 100k
RCLPROG = 2k
108
106
1000
VCLPROG (mV)
IIN (mA)
102
100
98
96
485
94
475
–50
90
–50
VIN = 5V
RCLPROG = 2k
HPWR = 5V
104
495
100
4066 G03
Input Current Limit vs
Temperature, HPWR = 0V
525
IIN (mA)
50
25
0
TEMPERATURE (°C)
4066 G02
4066 G01
505
–25
800
600
400
HPWR = 0V
200
92
–25
0
25
50
TEMPERATURE (°C)
75
100
–25
25
50
0
TEMPERATURE (°C)
4066 G04
1.015
0
–50
100
4.300
4.220
RPROG = 34k
TA = 25°C
4.250
VFLOAT (V)
VFLOAT (V)
VPROG (V)
LTC4066
4.180
4.150
4.160
4.140
LTC4066-1
4.100
4.120
0.990
LTC4066-1
4.050
0.985
0.980
–50
100
VIN = 5V
4.200
LTC4066
4.200
0.995
75
Battery Regulation (Float)
Voltage vs Temperature
1.010
1.000
0
25
50
TEMPERATURE (°C)
4066 G06
VFLOAT Load Regulation
VIN = 5V
RPROG = 100k
1.005
–25
4066 G05
PROG Pin Voltage vs Temperatrue
1.020
75
–25
0
50
25
TEMPERATURE (°C)
4.000
75
100
4066 G07
4.100
0
250
500
750 1000
IBAT (mA)
1250
1500
4066 G08
4.080
–50
–25
0
50
25
TEMPERATURE (°C)
75
100
4066 G09
4066fc
5
LTC4066/LTC4066-1
TYPICAL PERFORMANCE CHARACTERISTICS
Regulated Output Voltage–
Recharge Threshold Voltage
vs Temperature
120
225
VIN = 5V
200
6
500
5
RON (mΩ)
100
95
IBAT (mA)
VIN = 5V
175
105
400
4
300
3
VIN = 4.5V
VIN = 5.5V
150
125
200
2
400mAhr CELL
VIN = 5V
TA = 25°C
RPROG = 105k
90
100
80
–50
–25
0
50
25
TEMPERATURE (°C)
100
1
0
0
75
–50
100
75
75
0
25
50
TEMPERATURE (°C)
–25
100
0
50
100
TIME (MINUTES)
150
4066 G11
4066 G10
Charging from USB, IBAT vs VBAT
(LTC4066)
4066 G12
Charging from USB, Low Power,
IBAT vs VBAT (LTC4066)
600
Undervoltage Current Limit
IBAT vs VOUT
120
VIN = 5V
VOUT = NO LOAD
500 RPROG = 100k
RCLPROG = 2k
HPWR = 5V
400 T = 25°C
A
1500
1250
TA = 25°C
WALL = 2V
VBAT = 3.5V
1000
IBAT (mA)
IBAT (mA)
VIN = 5V
VOUT = NO LOAD
100 RPROG = 100k
RCLPROG = 2k
HPWR = 0V
80 T = 25°C
A
300
VBAT AND VCHRG (V)
110
85
IBAT (mA)
600
ILOAD = 400mA
115
VFLOAT – VRECHG (mV)
Battery Current and Voltage
vs Time (LTC4066)
Input RON vs Temperature
60
RPROG = 34k
750
RPROG = 50k
200
40
500
100
20
250
RPROG = 100k
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
VBAT (V)
0
0
4066 G13
4.0
RPROG = 50k
4.5
25°C
3.0
IOUT (A)
2.5
–50°C
2.0
125°C
IOUT (A)
0°C
75°C
225
VBAT = 3.5V
VIN = 0V
TA = 25°C
4.0
200
3.5
175
3.0
150
2.5
125
2.0
100
1.5
1.5
250
1.0
VIN = 5V
VBAT = 3.5V
QJA = 43°C/W
0
–50
–25
75
0
25
50
TEMPERATURE (°C)
0.5
100
125
4066 G16
RDIO(ON)
1.0
RFWD
0.5
0
0
20 40 60 80 100 120 140 160 180 200
VFWD (mV)
4066 G17
0
0
75
RESISTANCE (mΩ)
IBAT (mA)
750
4.50
4.40
Ideal Diode Resistance and
Current vs Forward Voltage
VBAT = 3.7V
VIN = 0V
3.5
RPROG = 100k
4.20
4.30
VOUT (V)
4066 G15
Ideal Diode Current vs Forward
Voltage and Temperature
500
4.10
4066 G14
Charge Current vs Temperature
(Thermal Regulation)
1000
0
4.00
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
VBAT (V)
50
25
0
20 40 60 80 100 120 140 160 180 200
VFWD (mV)
4066 G18
4066fc
6
LTC4066/LTC4066-1
TYPICAL PERFORMANCE CHARACTERISTICS
ISTAT Pin Current vs
Battery Current
ISTAT Pin Current vs Battery
Current (Low Currents)
10
1500
IDEAL DIODE
IDEAL DIODE
CHARGING
1250
CHARGING
8
IISTAT (μA)
IISTAT (μA)
1000
750
6
4
500
250
VBAT = 4.2V
VIN = 5V
TA = 25°C
RPROG = 34k
0
–1500 –1000 –500
2
0
500
IBAT (mA)
1000
VBAT = 4.2V
VIN = 5V
TA = 25°C
0
–10 –8 –6 –4 –2 0 2
IBAT (mA)
1500
4
6
Input Disconnect Waveforms
Response to HPWR
VIN
5V/DIV
VIN
5V/DIV
VOUT
5V/DIV
VOUT
5V/DIV
IIN
0.5A/DIV
IIN
0.5A/DIV
IIN
0.5A/DIV
IBAT
0.5A/DIV
IBAT
0.5A/DIV
IBAT
0.5A/DIV
VBAT = 3.85V
IOUT = 100mA
1ms/DIV
4066 G21
HPWR
5V/DIV
VBAT = 3.85V
IOUT = 100mA
WALL Connect Waveforms,
VIN = 0V
1ms/DIV
4066 G22
VBAT = 3.85V
IOUT = 50mA
WALL Disconnect Waveforms,
VIN = 0V
WALL
5V/DIV
SUSPEND
5V/DIV
VOUT
5V/DIV
VOUT
5V/DIV
VOUT
5V/DIV
IWALL
0.5A/DIV
IWALL
0.5A/DIV
IIN
0.5A/DIV
IBAT
0.5A/DIV
IBAT
0.5A/DIV
IBAT
0.5A/DIV
1ms/DIV
4066 G24
VBAT = 3.85V
IOUT = 100mA
RPROG = 71.5k
1ms/DIV
4066 G25
1ms/DIV
4066 G23
Respond to Suspend
WALL
5V/DIV
VBAT = 3.85V
IOUT = 100mA
RPROG = 71.5k
10
4066 G20
4006 G19
Input Connect Waveforms
8
VBAT = 3.85V
IOUT = 50mA
1ms/DIV
4066 G26
4066fc
7
LTC4066/LTC4066-1
TYPICAL PERFORMANCE CHARACTERISTICS
WALL Disconnect Waveforms,
VIN = 5V
WALL Connect Waveforms,
VIN = 5V
WALL
5V/DIV
IIN
0.5A/DIV
WALL
5V/DIV
IIN
0.5A/DIV
IWALL
0.5A/DIV
IWALL
0.5A/DIV
IBAT
0.5A/DIV
IBAT
0.5A/DIV
VBAT = 3.85V
IOUT = 100mA
RPROG = 71.5k
1ms/DIV
4066 G27
VBAT = 3.85V
IOUT = 100mA
RPROG = 71.5k
1ms/DIV
4066 G28
PIN FUNCTIONS
OUT (Pins 1, 3, 8): Voltage Output. This pin is used to
provide controlled power to a USB device from either
USB VBUS (IN) or the battery (BAT) when the USB is not
present. This pin can also be used as an input for battery
charging when the USB is not present and a wall adapter
is applied to this pin. OUT should be bypassed with at least
4.7μF to GND. Connect Pins 1, 3 and 8 with a resistance
no greater than 10mΩ.
BAT (Pins 2, 4, 5): Connect to a single cell Li-Ion battery.
This pin is used as an output when charging the battery, and
as an input when supplying power to OUT. When the OUT
pin potential drops below the BAT pin potential, an ideal
diode function connects BAT to OUT and prevents VOUT from
dropping more than 50mV below VBAT . A precision internal
resistor divider sets the final float (charging) potential on
this pin. The internal resistor divider is disconnected when
IN and OUT are in undervoltage lockout. Connect Pins 2,
4 and 5 with a resistance no greater than 10mΩ.
IN (Pin 9): Input Supply. Connect to USB supply, VBUS.
Input current to this pin is limited to either 20% or 100% of
the current programmed by the CLPROG pin as determined
by the state of the HPWR pin. The input current limit can
also be disabled by pulling CLDIS high. Charge current (to
BAT pin) supplied through the input is set to the current
programmed by the PROG pin but will be limited by the
input current limit if charge current is set greater than the
input current limit.
CLDIS (Pin 10): Current Limit Disable. This logic input
is used to disable the input current limit programmed by
CLPROG. A voltage greater than 1.2V on the pin will set
the current limit to IIN(MAX) (typically 2.6A). A weak pulldown current is internally applied to this pin to ensure
it is low at power-up when the input is not being driven
externally.
SUSP (Pin 11): Suspend Mode Input. Pulling this pin
above 1.2V will disable the power path from IN to OUT. The
supply current from IN will be reduced to comply with the
USB specification for Suspend mode. Both the ability to
charge the battery from OUT and the ideal diode function
(from BAT to OUT) will remain active. Suspend mode will
reset the charge timer if VOUT is less than VBAT while in
suspend mode. If VOUT is kept greater than VBAT, such as
when a wall adapter is present, the charge timer will not be
reset when the part is put in suspend. A weak pull-down
current is internally applied to this pin to ensure it is low
at power-up when the pin is not being driven externally.
4066fc
8
LTC4066/LTC4066-1
PIN FUNCTIONS
SHDN (Pin 12): Shutdown Input. Pulling this pin greater
than 1.2V will disable the entire part and place it in a low
supply current mode of operation. All power paths will be
disabled. A weak pull-down current is internally applied
to this pin to ensure it is enabled at power-up when the
pin is not being driven externally.
ACPR (Pin 17): Wall Adapter Present Output. Active low
open-drain output pin. A low on this pin indicates that the
wall adapter input comparator has had its input pulled
above the input threshold. This feature is disabled if the
part is shut down or if no power is present on IN or OUT
or BAT (i.e., below UVLO thresholds).
HPWR (Pin 13): High Power Select. This logic input is used
to control the input current limit. A voltage greater than
1.2V on the pin will set the input current limit to 100% of
the current programmed by the CLPROG pin. A voltage
less than 0.4V on the pin will set the input current limit
to 20% of the current programmed by the CLPROG pin.
A weak pull-down current is internally applied to this pin
to ensure it is low at power-up when the pin is not being
driven externally.
CHRG (Pin 18): Open-Drain Charge Status Output. When
the battery is being charged, the CHRG pin is pulled low by
an internal N-channel MOSFET. When the timer runs out or
the charge current drops below a programmable current
level or the input supply or output supply is removed, the
CHRG pin is forced to a high impedance state.
NTC (Pin 14): Input to the NTC Thermistor Monitoring
Circuits. Under normal operation, tie a thermistor from
the NTC pin to ground and a resistor of equal value from
NTC to VNTC. When the voltage on this pin is above 0.74
• VVNTC (Cold, 0°C) or below 0.29 • VVNTC (Hot, 50°C)
the timer is suspended, but not cleared, the charging is
disabled and the CHRG pin remains in its former state.
When the voltage on NTC comes back between 0.74 •
VVNTC and 0.29 • VVNTC, the timer continues where it left
off and charging is re-enabled if the battery voltage is
below the recharge threshold. There is approximately 3°C
of temperature hysteresis associated with each of the input
comparators. Connect the NTC pin to ground to disable
this feature. This will disable all of the LTC4066/LTC4066-1
NTC functions.
VNTC (Pin 15): Output Bias Voltage for NTC. A resistor from
this pin to the NTC pin will bias the NTC thermistor.
GND (Pin 16), Exposed Pad (Pin 25): Ground. The Exposed
Pad is ground and must be soldered to the PC board for
maximum heat transfer. The Exposed Pad must be electrically connected to the GND pin.
POL (Pin 19): Battery Current Status Polarity Pin. This
open-drain output pin indicates whether the current flowing
out of the ISTAT pin represents one-thousandth of the current flowing into or out of the BAT pins. The POL pin will
pull down when current is flowing out of the BAT pin (i.e.,
charging) and will assume a high impedance state when
current is flowing into the BAT pin (i.e., ideal diode).
WALL (Pin 20): Wall Adapter Present Input. Pulling this
pin above 1.225V will disconnect the power path from IN
to OUT. The ACPR pin will also be pulled low to indicate
that a wall adapter has been detected.
TIMER (Pin 21): Timer Capacitor. Placing a capacitor,
CTIMER, to GND sets the timer period. The timer period
is:
t TIMER(Hours) =
CTIMER • RPROG • 3Hours
0.1μF • 100k
Charge time is increased if charge current is reduced due
to load current, thermal regulation and current limit selection (HPWR). Shorting the TIMER pin to GND disables the
battery charging functions.
4066fc
9
LTC4066/LTC4066-1
PIN FUNCTIONS
CLPROG (Pin 22): Current Limit Program and Input Current Monitor. Connecting a resistor, RCLPROG, to ground
programs the input to output current limit. The current
limit is programmed as follows:
ICL ( A) =
1000 V
RCLPROG
In USB applications the resistor RCLPROG should be set
to no less than 2.1k.
The voltage on the CLPROG pin is always proportional to
the current flowing through the IN to OUT power path.
This current can be calculated as follows:
IIN( A) =
VCLPROG
• 1000
RCLPROG
PROG (Pin 23): Charge Current Program. Connecting a
resistor, RPROG, to ground programs the battery charge
current. The battery charge current is programmed as
follows:
ICHG( A) =
50, 000 V
RPROG
ISTAT (Pin 24): Battery Current Status Pin. One-thousandth
of the current flowing into or out of the BAT pins flows
out of this pin. The POL polarity pin indicates which
direction current is flowing. If the current flowing into
the BAT pins drops below 1mA, then the ISTAT pin will
continue to source 1μA. The ISTAT pin also programs the
charge current level at which the CHRG pin transitions to
its high impedance state. When the ISTAT voltage drops
below 0.1V while charging in constant voltage mode the
CHRG pin will transition to a high impedance state. This
corresponds to a BAT current of:
IBAT ( A) =
0.1V
• 1000
RISTAT
4066fc
10
LTC4066/LTC4066-1
BLOCK DIAGRAM
VBUS
1,3,8
9
IN
2,4,5
BAT
OUT
–+
10
CURRENT LIMIT DISABLE
CLDIS
25mV
CURRENT LIMIT
2μA
IN
CHARGER
CC/CV REGULATOR
ENABLE
OUT
ILIM CNTL
ENABLE
1V
IIN
1000
22
+
19
CP
–
DIE
TEMP
HPWR
POL
–
ILIM
CURRENT CONTROL
100k
13
BAT
SOFT-START
+
CL
CLPROG
IDEAL
DIODE
105°C
+
–
500mA/100mA
IN OUT BAT
TA
2μA
SOFT-START2
CHRG
CHARGE CONTROL
+
+
1V
CHG
–
0.25V
+
2.9V
BATTERY
UVLO
–
23
PROG
BAT UV
100k
20
WALL
1.25V
17
+
–
–
+
ACPR
VOLTAGE DETECT
4.1V
RECHARGE
(4.0V
LTC4066-1)
–
UVLO
BAT UV
15
VNTC
RECHRG
TIMER
OSCILLATOR
–
100k
HOLD
14
NTCERR
+
CHRG
CLK
TOOCOLD
NTC
21
CONTROL LOGIC
18
STOP
RESET
COUNTER
NTC
–
100k
TOOHOT
+
0.1V
|IBAT|
1000
EOC
–
+
NTC ENABLE
0.1V
+
2μA
2μA
–
16
GND
12
SHDN
11
SUSP
ISTAT
24
4066 BD
2k
4066fc
11
LTC4066/LTC4066-1
OPERATION
The LTC4066/LTC4066-1 are complete PowerPathTM
controllers for battery-powered USB applications. The
LTC4066/LTC4066-1 are designed to receive power from a
USB source, a wall adapter or a battery. It can then deliver
power to an application connected to the OUT pin and a
battery connected to the BAT pin (assuming that an external
supply other than the battery is present). Power supplies
that have limited current resources (such as USB VBUS
supplies) should be connected to the IN pin which has a
programmable current limit. Battery charge current will
be adjusted to ensure that the sum of the charge current
and load current does not exceed the programmed input
current limit.
An ideal diode function provides power from the battery
when output/load current exceeds the input current limit or
when input power is removed. Powering the load through
the ideal diode instead of connecting the load directly to
the battery allows a fully charged battery to remain fully
charged until external power is removed. Once external
power is removed, the output drops until the ideal diode
is forward biased. The forward biased ideal diode will then
provide the output power to the load from the battery.
Furthermore, powering switching regulator loads from the
OUT pin (rather than directly from the battery), results in
shorter battery charge times. This is due to the fact that
switching regulators typically require constant input power.
When this power is drawn from the OUT pin voltage (rather
than the lower BAT pin voltage) the current consumed
by the switching regulator is lower, leaving more current
available to charge the battery.
The LTC4066/LTC4066-1 also have the ability to receive
power from a wall adapter. Wall adapter power can be connected to the output (load side) of the LTC4066/LTC4066-1
through an external device such as a power Schottky or
FET, as shown in Figure 1. The LTC4066/LTC4066-1 have
the unique ability to use the output, which is powered
by the wall adapter, as a path to charge the battery while
providing power to the load. A wall adapter comparator
on the LTC4066/LTC4066-1 can be configured to detect
the presence of the wall adapter and shut off the connection to the USB to prevent reverse conduction out to the
USB bus.
PowerPath is a trademark of Linear Technology Corporation.
WALL
ADAPTER
USB VBUS
CURRENT LIMIT
CONTROL
IN
9
OUT
1,3,8
ENABLE
LOAD
CHRG
CONTROL
20
WALL
IDEAL
DIODE
+
BAT
2,4,5
1.25V
+
–
Li-Ion
4066 F01
Figure 1. Simplified Block Diagram—PowerPath
4066fc
12
LTC4066/LTC4066-1
OPERATION
Table 1. Operating Modes—PowerPath States
Current Limited Input Power (IN to OUT)
WALL PRESENT
SHUTDOWN
SUSPEND
VIN > 3.8V
VIN > (VOUT + 100mV)
VIN > (VBAT + 100mV)
CURRENT LIMIT ENABLED
Y
X
X
X
X
X
N
X
Y
X
X
X
X
N
X
X
Y
X
X
X
N
X
X
X
N
X
X
N
X
X
X
X
N
X
N
X
X
X
X
X
N
N
N
N
N
Y
Y
Y
Y
Battery Charger (OUT to BAT)
WALL PRESENT
SHUTDOWN
SUSPEND
VOUT > 4.35V
VOUT > (VBAT + 100mV)
CHARGER ENABLED
X
Y
X
X
X
N
X
X
X
N
X
N
X
X
X
X
N
N
X
N
X
Y
Y
Y
Ideal Diode (BAT to OUT)
WALL PRESENT
SHUTDOWN
SUSPEND
VBAT > 2.8V
VBAT > VOUT
VIN
DIODE ENABLED
X
Y
X
X
X
X
N
X
X
X
N
X
X
N
X
X
X
X
N
X
N
X
N
X
Y
Y
X
Y
Table 2. Operating Modes—Pin Currents vs Programmed Currents (Powered from IN)
PROGRAMMING
OUTPUT CURRENT
BATTERY CURRENT
INPUT CURRENT
ICL = ICHG
IOUT < ICL
IOUT = ICL = ICHG
IOUT > ICL
IBAT = ICHG – IOUT
IBAT = 0
IBAT = ICL – IOUT
IIN = IQ + ICL
IIN = IQ + ICL
IIN = IQ + ICL
ICL > ICHG
IOUT < (ICL – ICHG)
IOUT > (ICL – ICHG)
IOUT = ICL
IOUT > ICL
IBAT = ICHG
IBAT = ICL – IOUT
IBAT = 0
IBAT = ICL – IOUT
IIN = IQ + ICHG + IOUT
IIN = IQ + ICL
IIN = IQ + ICL
IIN = IQ + ICL
ICL < ICHG
IOUT < ICL
IOUT > ICL
IBAT = ICL – IOUT
IBAT = ICL – IOUT
IIN = IQ + ICL
IIN = IQ + ICL
4066fc
13
14
VOUT < VBAT
VOUT > VBAT
VOUT < VBAT
BATTERY POWERS VOUT
• CHARGING SUSPENDED
• CHRG PULLED LOW
VIN POWERS PART
VIN CHARGING BATTERY
BATTERY < 4.1V
(4.0V LTC4066-1)
• CURRENT LIMIT FROM
IN TO OUT ENABLED
WALL ADAPTER PRESENT
TEMP NOT OK
• CHRG IS HI-Z
• BATTERY POWER TO VOUT—DISABLED
BAD BATTERY
• BATTERY CHARGING ON
• CHARGE CURRENT C/10
• CHRG PULLED LOW
• BATTERY POWER TO VOUT IS OFF
VIN CHARGING LOW BATTERY
TEMP OK AND
BATTERY < 2.8V
1/4 TIMEOUT
AND
BATTERY < 2.8V
WALL ADAPTER PRESENT
1/4 TIMEOUT
AND
BATTERY < 2.8V
TEMP OK AND
BATTERY < 2.8V
• CHRG IS HI-Z
• BATTERY POWER TO VOUT—DISABLED
BAD BATTERY
• CURRENT LIMIT FROM IN TO OUT DISABLED
• BATTERY CHARGING ON
• CHARGE CURRENT C/10
• CHRG PULLED LOW
• ACPR PULLED LOW
VOUT CHARGING LOW BATTERY
TEMP NOT OK
4066 SD
BATTERY > 2.8V
TEMP OK AND
BATTERY > 2.8V
NTC FAULT
BATTERY < 2.8V
TEMP NOT OK
• BATTERY CHARGING SUSPENDED
• CHRG PULLED LOW
BATTERY < 2.8V
WALL ADAPTER PRESENT
VOUT CHARGING BATTERY
BATTERY < 4.1V
(4.0V LTC4066-1)
• CURRENT LIMIT FROM IN TO OUT DISABLED
• BATTERY CHARGING ON
• CHRG PULLED LOW
• ACPR PULLED LOW
BATTERY > 4.1V
(4.0V LTC4066-1)
AND CHARGER
TIMED OUT
• CURRENT LIMIT FROM
IN TO OUT DISABLED
• ACPR PULLED LOW
VOUT POWERS PART
WALL ADAPTER PRESENT
NTC FAULT
TEMP NOT OK
LOW BATTERY
BATTERY < 2.8V
• CHRG IS HI-Z
• BATTERY POWER TO VOUT—DISABLED
BATTERY > 2.8V
BATTERY > 4.1V
(4.0V LTC4066-1)
AND CHARGER
TIMED OUT
SHDN
• CHARGING DISABLED
• BATTERY POWERS VOUT
UVLO
• CHARGING DISABLED
• ALL SWITCHES OPEN
SHUTDOWN
• BATTERY CHARGING SUSPENDED
• CHRG PULLED LOW
TEMP OK AND
BATTERY > 2.8V
• CURRENT LIMIT FROM IN TO OUT ENABLED
• BATTERY CHARGING ON
• CHRG PULLED LOW
BATTERY > 2.8V
VOUT > VBAT
BATTERY POWERS VOUT
• CHARGING SUSPENDED
• CHRG HIGH-Z
POWER APPLIED TO VIN
(VIN AND VOUT) < UVLO
SHUTDOWN
Operatinal State Diagram
LTC4066/LTC4066-1
OPERATION
4066fc
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
USB Current Limit and Charge Current Control
The current limit and charger control circuits of the
LTC4066/LTC4066-1 are designed to limit input current as
well as control battery charge current as a function of IOUT .
The programmed input current limit, ICL, is defined as:
⎛ 1000
⎞
1000 V
ICL = ⎜
• VCLPROG⎟ =
⎝ RCLPROG
⎠ RCLPROG
The programmed battery charge current, ICHG, is defined
as:
⎛ 50, 000
⎞ 50, 000 V
ICHG = ⎜
• VPROG⎟ =
⎝ RPROG
⎠
RPROG
The LTC4066/LTC4066-1 reduce battery charge current
such that the sum of the battery charge current and the
load current does not exceed the programmed input current
limit (one-fifth of the programmed input current limit when
HPWR is low, see Figure 2). The battery charge current
goes to zero when load current exceeds the programmed
input current limit (one-fifth of the limit when HPWR is
low). If the load current is greater than the current limit, the
output voltage will drop to just under the battery voltage
where the ideal diode circuit will take over and the excess
load current will be drawn from the battery.
Programming Current Limit
The formula for input current limit is:
Input current, IIN, is equal to the sum of the BAT pin output
current and the OUT pin output current:
IIN = IOUT + IBAT
The current limiting circuitry in the LTC4066/LTC4066-1
can and should be configured to limit current to 500mA
for USB applications (selectable using the HPWR pin and
programmed using the CLPROG pin).
⎛ 1000
⎞
1000 V
ICL = ⎜
• VCLPROG⎟ =
⎝ RCLPROG
⎠ RCLPROG
where VCLPROG is the CLPROG pin voltage and RCLPROG is
the total resistance from the CLPROG pin to ground.
For example, if typical 500mA current limit is required,
calculate:
RCLPROG =
600
1V
• 1000 = 2k
500mA
120
IIN
500
600
IIN
100
500
IIN
ILOAD
300
200
IBAT
CHARGING
400
ILOAD
60
40
IBAT
CHARGING
CURRENT (mA)
80
CURRENT (mA)
CURRENT (mA)
400
ILOAD
300
200
100
20
100
0
0
0
–100
0
100
200
300
400
ILOAD (mA)
500
600
IBAT
(IDEAL DIODE)
–20
0
20
40
60
80
ILOAD (mA)
100
120
IBAT
(IDEAL DIODE)
4066 F02a
4066 F02a
(2a) High Power Mode/Full Charge
RPROG = 100k and RCLPROG = 2k
(2b) Low Power Mode/Full Charge
RPROG = 100k and RCLPROG = 2k
IBAT = ICHG
–100
IBAT
CHARGING
0
100
200
IBAT = ICL – IOUT
300
400
ILOAD (mA)
500
600
IBAT
(IDEAL DIODE)
4055 F02c
(2c) High Power Mode with
ICL = 500mA and ICHG = 250mA
RPROG = 200k and RCLPROG = 2k
Figure 2. Input and Battery Currents as a Function of Load Current
4066fc
15
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
In USB applications, the minimum value for RCLPROG
should be 2.1k. This will prevent the application current
from exceeding 500mA due to LTC4066/LTC4066-1 tolerances and quiescent currents. A 2.1k CLPROG resistor will
give a typical current limit of 476mA in high power mode
(HPWR = 1) or 95mA in low power mode (HPWR = 0).
VCLPROG will typically servo to 1V; however, if IOUT + IBAT
< ICL then VCLPROG will track the input current according
to the following equation:
IIN =
VCLPROG
• 1000
RCLPROG
For best stability over temperature and time, 1% metal
film resistors are recommended.
Ideal Diode from BAT to OUT
If a battery is the only power supply available or if the load
current exceeds the programmed input current limit, then
the battery will automatically deliver power to the load via
an ideal diode circuit between the BAT and OUT pins. The
ideal diode circuit (along with the recommended 4.7μF
capacitor on the OUT pin) allows the LTC4066/LTC4066-1
to handle large transient loads and wall adapter or USB
VBUS connect/disconnect scenarios without the need for
large bulk capacitors. The ideal diode responds within a
few microseconds and prevents the OUT pin voltage from
dipping below the BAT pin voltage by more than 50mV.
Forward regulation for the ideal diode from BAT to OUT
has three operational ranges, depending on the magnitude of the diode load current. For small load currents,
the LTC4066/LTC4066-1 will provide a constant voltage
drop; this operating mode is referred to as “constant
VON” regulation. As the current exceeds IFWD the voltage
drop will increase linearly with the current with a slope of
1/RDIO(ON); this operating mode is referred to as “constant
RON” regulation. As the current increases further, exceeding
IMAX, the forward voltage drop will increase rapidly; this
operating mode is referred to as “constant ION” regulation.
The characteristics for parameters RFWD, RON, VFWD and
IFWD are specified with the aid of Figure 3.
CONSTANT
ION
LTC4066
IMAX
CONSTANT
RON
CURRENT (A)
SLOPE: 1/RDIO(ON)
IFWD
SLOPE: 1/RFWD
0
SCHOTTKY
DIODE
CONSTANT
VON
4066 F03
VFWD
FORWARD VOLTAGE (V)
Figure 3. LTC4066/LTC4066-1 vs Schottky Diode Forward Voltage Drop
4066fc
16
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
Battery Charger
The battery charger circuits of the LTC4066/LTC4066-1
are designed for charging single cell lithium-ion batteries. Featuring an internal P-channel power MOSFET, the
charger uses a constant-current/constant-voltage charge
algorithm with programmable current and a programmable timer for charge termination. Charge current can be
programmed up to 1.5A. The final float voltage accuracy
is ±0.8% typical. No blocking diode or sense resistor is
required when powering the IN pin. The CHRG open-drain
status output provides information regarding the charging
status of the LTC4066/LTC4066-1 at all times. An NTC
input provides the option of charge qualification using
battery temperature.
An internal thermal limit reduces the programmed charge
current if the die temperature attempts to rise above a
preset value of approximately 105°C. This feature protects
the LTC4066/LTC4066-1 from excessive temperature, and
allows the user to push the limits of the power handling
capability of a given circuit board without risk of damaging the LTC4066/LTC4066-1. Another benefit of the
LTC4066/LTC4066-1 thermal limit is that charge current
can be set according to typical, not worst-case, ambient
temperatures for a given application with the assurance
that the charger will automatically reduce the current in
worst-case conditions.
The charge cycle begins when the voltage at the OUT pin
rises above the output UVLO level and the battery voltage
is below the recharge threshold. No charge current actually
flows until the OUT voltage is greater than the output UVLO
level and 100mV above the BAT voltage. At the beginning
of the charge cycle, if the battery voltage is below 2.8V,
the charger goes into trickle charge mode to bring the
cell voltage up to a safe level for charging. The charger
goes into the fast charge constant-current mode once
the voltage on the BAT pin rises above 2.8V. In constantcurrent mode, the charge current is set by RPROG. When
the battery approaches the final float voltage, the charge
current begins to decrease as the LTC4066/LTC4066-1
switches to constant-voltage mode. When the charge
current drops below a level programmed by the ISTAT pin
while in constant-voltage mode the CHRG pin assumes a
high impedance state.
An external capacitor on the TIMER pin sets the total
minimum charge time. When this time elapses the
charge cycle terminates and the CHRG pin assumes a
high impedance state, if it has not already done so. While
charging in constant-current mode, if the charge current
is decreased by thermal regulation or in order to maintain
the programmed input current limit the charge time is
automatically increased. In other words, the charge time
is extended inversely proportional to charge current delivered to the battery. For Li-Ion and similar batteries that
require accurate final float potential, the internal bandgap
reference, voltage amplifier and the resistor divider provide
regulation with ±0.8% accuracy.
Trickle Charge and Defective Battery Detection
At the beginning of a charge cycle, if the battery voltage
is low (below 2.8V) the charger goes into trickle charge
reducing the charge current to 10% of the full-scale current.
If the low-battery voltage persists for one quarter of the
total charge time, the battery is assumed to be defective,
the charge cycle is terminated and the CHRG pin output
assumes a high impedance state. If for any reason the
battery voltage rises above ~2.8V, the charge cycle will
be restarted. To restart the charge cycle (i.e., when the
dead battery is replaced with a discharged battery), simply
remove the input voltage and reapply it, cycle the TIMER
pin to 0V or cycle the SHDN pin to 0V.
4066fc
17
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
Programming Charge Current
The formula for the battery charge current is:
ICHG = (IPROG ) • 50, 000 =
VPROG
• 50, 000
RPROG
where VPROG is the PROG pin voltage and RPROG is the
total resistance from the PROG pin to ground. Keep in
mind that when the LTC4066/LTC4066-1 are powered
from the IN pin, the programmed input current limit takes
precedence over the charge current. In such a scenario,
the charge current cannot exceed the programmed input
current limit.
For example, if typical 500mA charge current is required,
calculate:
⎛ 1V ⎞
RPROG = ⎜
⎟ • 50, 000 = 100k
⎝ 500mA ⎠
For best stability over temperature and time, 1% metal
film resistors are recommended. Under trickle charge
conditions, this current is reduced to 10% of the fullscale value.
Monitoring Charge Current
The ISTAT and POL pins provide a means for monitoring
the BAT pin current. The ISTAT pin sources a current equal
to one-thousandth of the absolute value of the current
flowing in the BAT pin. The POL pin indicates the polarity
of the BAT pin current. When current is flowing from OUT
to BAT (i.e., charging), the POL pin pulls to ground. When
current is flowing from BAT to OUT (ideal diode), the POL
pin assumes a high impedance. If a resistor, RISTAT , is
placed from the ISTAT pin to ground, then the formula for
BAT current is:
IBAT =
where VISTAT is the ISTAT pin voltage and RISTAT is the total
resistance from the ISTAT pin to ground. These pins enable
a true gas gauge function to be performed on the battery
with an external ADC and integrator. See Gas Gauge for
more information.
The Charge Timer
The programmable charge timer is used to terminate the
charge cycle. The timer duration is programmed by an
external capacitor at the TIMER pin. The charge time is
typically:
t TIMER(Hours) =
CTIMER • RPROG • 3Hours
0.1μF • 100k
The timer starts when an input voltage greater than the
undervoltage lockout threshold level is applied or when
leaving shutdown and the voltage on the battery is less than
the recharge threshold. At power-up or exiting shutdown
with the battery voltage less than the recharge threshold,
the charge time is a full cycle. If the battery is greater than
the recharge threshold, the timer will not start and charging
is prevented. If after power-up the battery voltage drops
below the recharge threshold, or if after a charge cycle
the battery voltage is still below the recharge threshold,
the charge time is set to one-half of a full cycle.
The LTC4066/LTC4066-1 have a feature that extends charge
time automatically. Charge time is extended if the charge
current in constant-current mode is reduced due to load
current or thermal regulation. This change in charge time
is inversely proportional to the change in charge current.
As the LTC4066/LTC4066-1 approach constant-voltage
mode the charge current begins to drop. This change in
charge current is due to normal charging operation and
does not affect the timer duration.
VISTAT
• 1000
RISTAT
4066fc
18
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
Consider, for example, a USB charge condition where
RCLPROG = 2k, RPROG = 100k and CTIMER = 0.1μF. This
corresponds to a three hour charge cycle. However, if the
HPWR input is set to a logic low, then the input current
limit will be reduced from 500mA to 100mA. With no additional system load, this means the charge current will
be reduced to 100mA. Therefore, the termination timer
will automatically slow down by a factor of five until the
charger reaches constant voltage mode (i.e., VBAT = 4.2V,
4.1V for LTC4066-1) or HPWR is returned to a logic high.
The charge cycle is automatically lengthened to account for
the reduced charge current. The exact time of the charge
cycle will depend on how long the charger remains in
constant current mode and/or how long the HPWR pin
remains a logic low.
Once a time-out occurs and the voltage on the battery is
greater than the recharge threshold, the charge current
stops, and the CHRG output assumes a high impedance
state if it has not already done so.
Connecting the TIMER pin to ground disables the battery
charger.
CHRG Status Output Pin
When the charge cycle starts, the CHRG pin is pulled
to ground by an internal N-channel MOSFET capable of
driving an LED. When the charge current drops below a
programmable threshold while in constant-voltage mode,
the pin assumes a high impedance state (but charge current
continues to flow until the charge time elapses). If this
state is not reached before the end of the programmable
charge time, the pin will assume a high impedance state
when a time-out occurs.
The current level at which the CHRG pin changes state is
programmed by the ISTAT pin. As described in Monitoring
Charge Current and Gas Gauge, the ISTAT pin sources a
current proportional to the BAT pin current. The LTC4066/
LTC4066-1 monitor the voltage on the ISTAT pin and turns
off the CHRG N-channel pull-down when VISTAT drops
below 100mV while in constant-voltage mode. The CHRG
current detection threshold can be calculated by the following equation:
IDETECT =
0.1V
100 V
• 1000 =
RISTAT
RISTAT
For example, to program the CHRG pin to change state at
a battery charge current of 100mA, choose:
RISTAT =
100 V
= 1k
100mA
Note: The end-of-charge (EOC) comparator that monitors the ISTAT pin voltage for 100mV latches its decision.
Therefore, the first time VISTAT drops below 100mV (i.e.,
IBAT drops below 100V/RISTAT) while in constant voltage
mode will toggle CHRG to a high impedance state. If, for
some reason, the charge current rises back above the
threshold, the CHRG pin will not resume the strong pulldown state. The EOC latch can be reset by toggling the
SHDN pin or toggling the input power to the part. The EOC
latch will also be reset if the BAT pin voltage falls below
the recharge threshold.
4066fc
19
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
NTC Thermistor
The battery temperature is measured by placing a negative
temperature coefficient (NTC) thermistor close to the battery pack. The NTC circuitry is shown in Figure 4. To use
this feature, connect the NTC thermistor (RNTC) between
the NTC pin and ground and a resistor (RNOM) from the
NTC pin to VNTC. RNOM should be a 1% resistor with a
value equal to the value of the chosen NTC thermistor at
25°C (this value is 10k for a Vishay NTHS0603N02N1002J
thermistor). The LTC4066/LTC4066-1 go into hold mode
when the resistance (RHOT) of the NTC thermistor drops
to 0.41 times the value of RNOM or approximately 4.1k,
which should be at 50°C. The hold mode freezes the timer
and stops the charge cycle until the thermistor indicates a
return to a valid temperature. As the temperature drops,
the resistance of the NTC thermistor rises. The LTC4066/
LTC4066-1 are designed to go into hold mode when the
value of the NTC thermistor increases to 2.82 times the
VNTC
LTC4066
value of RNOM. This resistance is RCOLD. For a Vishay
NTHS0603N02N1002J thermistor, this value is 28.2k
which corresponds to approximately 0°C. The hot and cold
comparators each have approximately 3°C of hysteresis
to prevent oscillation about the trip point. Grounding the
NTC pin can disable the NTC function.
Thermistors
The LTC4066/LTC4066-1 NTC trip points were designed to
work with thermistors whose resistance-temperature characteristics follow Vishay Dale’s “R-T Curve 2”. The Vishay
NTHS0603N02N1002J is an example of such a thermistor.
However, Vishay Dale has many thermistor products that
follow the “R-T Curve 2” characteristic in a variety of sizes.
Furthermore, any thermistor whose ratio of RCOLD to RHOT
is about 7.0 will also work (Vishay Dale R-T Curve 2 shows
a ratio of RCOLD to RHOT of 2.815/0.4086 = 6.89).
VNTC
15
RNOM
10k
NTC
LTC4066
15
0.74 • VNTC
–
TOO_COLD
RNOM
121k
NTC
0.74 • VNTC
–
TOO_COLD
14
+
14
+
RNTC
10k
–
R1
13.3k
–
TOO_HOT
0.29 • VNTC
TOO_HOT
0.29 • VNTC
+
RNTC
100k
+
+
+
NTC_ENABLE
0.1V
–
NTC_ENABLE
0.1V
–
4066 F04a
(4a)
4055 F03b
(4b)
Figure 4. NTC Circuits
4066fc
20
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
Power conscious designs may want to use thermistors
whose room temperature value is greater than 10k. Vishay
Dale has a number of values of thermistor from 10k to
100k that follow the “R-T Curve 2.” Using these directly
in the manor spelled out previously in the NTC Thermistor
section will give temperature trip points of approximately
3°C and 47°C, a delta of 44°C. This delta in temperature
can be moved in either direction by changing the value of
RNOM with respect to RNTC. Increasing RNOM will move
both trip points to lower temperatures. Likewise a decrease
in RNOM with respect to RNTC will move the trip points to
higher temperatures. To calculate RNOM for a shift to lower
temperature for example, use the following equation:
RNOM =
RCOLD
• RNTC at 25°C
2.815
where RCOLD is the resistance ratio of RNTC at the desired
cold temperature trip point. If you want to shift the trip points
to higher temperatures, use the following equation:
RNOM =
RHOT
• RNTC at 25°C
0.4086
where RHOT is the resistance ratio of RNTC at the desired
hot temperature trip point.
Here is an example using a 100k R-T Curve 1 Thermistor
from Vishay Dale. The difference between the trip points
is 44°C, from before, and we want the cold trip point to
be 0°C, which would put the hot trip point at 44°C. The
RNOM needed is calculated as follows:
RCOLD
• RNTC at 25°C
2.815
3.266
=
• 100kΩ = 116kΩ
2.815
RNOM =
The nearest 1% value for RNOM is 115k. This is the value
used to bias the NTC thermistor to get cold and hot trip
points of approximately 0°C and 44°C respectively. To
extend the delta between the cold and hot trip points,
a resistor (R1) can be added in series with RNTC (see
Figure 3b). The values of the resistors are calculated as
follows:
RCOLD – RHOT
2.815 – 0.4086
0.4086
⎛
⎞
R1 = ⎜
⎟ • (RCOLD – RHOT ) – RHOT
⎝ 2.815 – 0.4086 ⎠
RNOM =
where RNOM is the value of the bias resistor, RHOT and
RCOLD are the values of RNTC at the desired temperature
trip points. Continuing the example from before with a
desired hot trip point of 50°C:
RCOLD – RHOT 100k • (3.266 – 0.3602)
=
2.815 – 0.4086
2.815 – 0.4086
= 120.8kΩ, 121k nearest 1%
RNOM =
⎡⎛
⎤
0.4086
⎞
R1 = 100k • ⎢⎜
⎟ • (3.266 – 0.3602) – 0.3602⎥
⎣⎝ 2.815 – 0.4086 ⎠
⎦
= 13.3kΩ, 13.3k is nearest 1%
The final solution is as shown if Figure 3b where RNOM =
121k, R1 = 13.3k and RNTC = 100k at 25°C.
Gas Gauge
The extremely low impedance of the ideal diode between
BAT and OUT (typically 50mΩ) allows users to connect
all of their loads to the OUT pin. Such a configuration puts
the LTC4066/LTC4066-1 in a unique position whereby it
can monitor all of the current that flows into and out of the
battery. Two output pins, ISTAT and POL, are provided to
enable users to monitor and integrate the battery current
for a true gas gauge function.
4066fc
21
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
Any time a battery is connected to the BAT pin and the
SHDN pin is low, the BAT pin current can be monitored
with the following equation:
IBAT =
VISTAT
• 1000
RISTAT
where |IBAT| is the absolute value of the BAT pin current,
VISTAT is the voltage on the ISTAT pin and RISTAT is the total
resistance from the ISTAT pin to ground.
The POL pin has two states: high impedance and strong
pull-down. High impedance indicates that current is flowing from BAT to OUT (ideal diode function) and strong
pull-down indicates that current is flowing from OUT to
BAT (charging). If an external ADC is used to convert the
ISTAT voltage, then the POL pin can be thought of as a
sign bit.
When the ideal diode function is operating, the ISTAT pin
cannot monitor ideal diode load currents less than about
1mA. For any ideal diode load current less than 1mA, the
ISTAT pin will source a constant current of approximately
1μA. However, when the battery charger function is operating, the ISTAT pin will continue to source one-thousandth
of the battery charge current even if the charge current
drops to less than 1mA.
When choosing the value of RISTAT, two details must be
considered. For the battery charger function, the value of
RISTAT programs the charge current below which the CHRG
pin transitions to its high impedance state (see CHRG
Status Output Pin). Furthermore, the available common
mode range on the ISTAT pin needed to maintain an accurate
ratio between IBAT and IISTAT is limited. When charging, the
ISTAT pin voltage should not exceed approximately VOUT
– 0.5V. When the ideal diode is functioning, the ISTAT pin
voltage should not exceed approximately VBAT – 0.5V (for
the typical minimum operating voltage for the ideal diode
this value would be 2.8V – 0.5V = 2.3V). Typically, it is this
second case that is the limiting situation since VBAT is typically lower than VOUT (while charging) and transient ideal
diode loads tend to be greater than typical charge currents
(causing a higher voltage on the ISTAT pin). Therefore,
choosing a value of RISTAT based on the CHRG detection
current may limit the maximum ideal diode load current
that can be sensed accurately. Consider an example:
a) Desired charge current = 850mA
b) Desired CHRG detection current = 100mA
c) Maximum transient ideal diode current = 1.5A
Calculate:
a) RPROG = (1V/850mA) • 50,000 = 59k
b) RISTAT = 100V/100mA = 1k
c) VISTAT(MAX) = 1.5A/1000 • 1k = 1.5V
In this example, there is no common mode problem because
the maximum ISTAT voltage (1.5V) is well below the 2.3V
minimum. However, if, instead of 100mA, the desired CHRG
detection current was lowered to 40mA, then the desired
RISTAT resistor would increase to 2.5k (100V/40mA) and
the maximum ISTAT voltage would increase to 3.75V (assuming no change in the 1.5A maximum ideal diode current). Therefore, ideal diode currents greater than 920mA
(2.3V/2.5k • 1000) might not be reported accurately. To
calculate the maximum ideal diode current that will be
reported accurately:
IDMON(MAX) =
VBAT – 0.5V
RISTAT
4066fc
22
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
Current Limit Undervoltage Lockout
Suspend
An internal undervoltage lockout circuit monitors the
input voltage and disables the input current limit circuits
until VIN rises above the undervoltage lockout threshold.
The current limit UVLO circuit has a built-in hysteresis of
125mV. Furthermore, to protect against reverse current in
the power MOSFET, the current limit UVLO circuit disables
the current limit (i.e., forces the input power path to a high
impedance state) if VOUT exceeds VIN. If the current limit
UVLO comparator is tripped, the current limit circuits will
not come out of shutdown until VOUT falls 50mV below
the VIN voltage.
The LTC4066/LTC4066-1 can be put in suspend mode by
forcing the SUSP pin greater than 1.2V. In suspend mode
the ideal diode function from BAT to OUT is kept alive.
If power is applied to the OUT pin externally (i.e., a wall
adapter is present) then charging will be unaffected. Current
drawn from the IN pin is reduced to 50μA. Suspend mode
is intended to comply with the USB Power Specification
mode of the same name.
Charger Undervoltage Lockout
An internal undervoltage lockout circuit monitors the VOUT
voltage and disables the battery charger circuits until
VOUT rises above the undervoltage lockout threshold. The
battery charger UVLO circuit has a built-in hysteresis of
125mV. Furthermore, to protect against reverse current
in the power MOSFET, the charger UVLO circuit keeps the
charger shutdown if VBAT exceeds VOUT. If the charger UVLO
comparator is tripped, the charger circuits will not come
out of shutdown until VOUT exceeds VBAT by 50mV.
Shutdown
The LTC4066/LTC4066-1 can be shutdown by forcing the
SHDN pin greater than 1.2V. In shutdown, the currents
drawn from IN, OUT and BAT are decreased to less than
2.5μA and the internal battery charge timer and end-ofcharge comparator output are reset. All power paths are
put in a high impedance state.
Selecting WALL Input Resistors
The WALL input pin identifies the presence of a wall adapter.
This information is used to disconnect the input pin, IN,
from the OUT pin in order to prevent back conduction to
whatever may be connected to the input. It also forces the
ACPR pin low when the voltage at the WALL pin exceeds
the input threshold. The WALL pin has a 1.225V rising
threshold and approximately 30mV of hysteresis.
The wall adapter detection threshold is set by the following equation:
⎛ R1⎞
VTH( Adapter ) = VWALL • ⎜ 1 + ⎟
⎝ R2 ⎠
⎛ R1⎞
VHYST ( Adapter ) = VWALL(HYST) • ⎜ 1 + ⎟
⎝ R2 ⎠
where VTH(Adapter) is the wall adapter detection threshold,
VWALL is the WALL pin rising threshold (typically 1.225V),
R1 is the resistor from the wall adapter input to WALL and
R2 is the resistor from WALL to GND.
4066fc
23
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
Consider an example where the VTH(Adapter) is to be set
somewhere around 4.5V. Resistance on the WALL pin
should be kept relatively low (~10k) in order to prevent
false tripping of the wall comparator due to leakages associated with the switching element used to connect the
adapter to OUT. Pick R2 to be 10k and solve for R1:
⎛ V ( Adapter ) ⎞
R1 = R2 • ⎜ TH
– 1⎟
⎝
⎠
VWALL
⎛ 4.5V
⎞
R1 = 10k • ⎜
– 1⎟ = 10k • 2.67 = 26.7k
⎝ 1.225V ⎠
The nearest 1% resistor is 26.7k. Therefore, R1 = 26.7k
and the rising trip point should be 4.50V.
⎛ 26.7k ⎞
VHYST ( Adapter ) ≈ 30mV • ⎜ 1 +
⎟ ≈ 110.1mV
⎝
10k ⎠
The hysteresis is going to be approximately 110mV for
this example.
However, the approximate ambient temperature at which
the thermal feedback begins to protect the IC is:
TA = 105°C – PD • θJA
TA = 105°C – (VOUT – VBAT) • IBAT • θJA
Example: Consider an LTC4066/LTC4066-1 operating from
a wall adapter with 5V at VOUT providing 0.8A to a 3V
Li-Ion battery. The ambient temperature above which the
LTC4066/LTC4066-1 will begin to reduce the 0.8A charge
current, is approximately:
TA = 105°C – (5V – 3V) • 0.8A • 37°C/W
TA = 105°C – 1.6W • 37°C/W = 105°C – 59°C = 46°C
The LTC4066/LTC4066-1 can be used above 46°C, but the
charge current will be reduced below 0.8A. The charge
current at a given ambient temperature can be approximated by:
IBAT =
Power Dissipation
The conditions that cause the LTC4066/LTC4066-1 to
reduce charge current due to the thermal protection
feedback can be approximated by considering the power
dissipated in the part. For high charge currents and a wall
adapter applied to VOUT , the LTC4066/LTC4066-1 power
dissipation is approximately:
PD = (VOUT – VBAT) • IBAT
where PD is the power dissipated, VOUT is the supply
voltage, VBAT is the battery voltage and IBAT is the battery
charge current. It is not necessary to perform any worstcase power dissipation scenarios because the LTC4066/
LTC4066-1 will automatically reduce the charge current
to maintain the die temperature at approximately 105°C.
105°C – TA
( VOUT – VBAT ) • θJA
Consider the above example with an ambient temperature of 55°C. The charge current will be reduced to
approximately:
IBAT =
105°C – 55°C
50°C
=
= 0.675A
(5V – 3V) • 37°C/W 74°C/A
Board Layout Considerations
In order to be able to deliver maximum charge current
under all conditions, it is critical that the Exposed Pad
on the backside of the LTC4066/LTC4066-1 package is
soldered to the board. Correctly soldered to a 2500mm2
double-sided 1oz. copper board, the LTC4066/LTC4066-1
has a thermal resistance of approximately 37°C/W. Failure
4066fc
24
LTC4066/LTC4066-1
APPLICATIONS INFORMATION
to make thermal contact between the Exposed Pad on the
backside of the package and the copper board will result
in thermal resistances far greater than 37°C/W. As an
example, a correctly soldered LTC4066/LTC4066-1 can
deliver over 1A to a battery from a 5V supply at room
temperature. Without a backside thermal connection, this
number could drop to less than 500mA.
Furthermore, Pins 6 and 7 are “true No Connect” pins.
Therefore, they can be used to improve the amount of
metal used to connect to Pin 5 or Pin 8.
VIN and Wall Adapter Bypass Capacitor
Many types of capacitors can be used for input bypassing.
However, caution must be exercised when using multilayer
ceramic capacitors. Because of the self resonant and high
Q characteristics of some types of ceramic capacitors, high
voltage transients can be generated under some start-up
conditions, such as connecting the charger input to a hot
power source. For more information, refer to Application
Note 88.
Stability
The constant-voltage mode feedback loop is stable without
any compensation when a battery is connected. However,
a 4.7μF capacitor with a 1Ω series resistor to GND is
recommended at the BAT pin to keep ripple voltage low
when the battery is disconnected.
4066fc
25
LTC4066/LTC4066-1
PACKAGE DESCRIPTION
UF Package
24-Lead Plastic QFN (4mm × 4mm)
(Reference LTC DWG # 05-08-1697)
0.70 p0.05
4.50 p 0.05
2.45 p 0.05
3.10 p 0.05 (4 SIDES)
PACKAGE OUTLINE
0.25 p0.05
0.50 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
4.00 p 0.10
(4 SIDES)
BOTTOM VIEW—EXPOSED PAD
R = 0.115
TYP
0.75 p 0.05
PIN 1 NOTCH
R = 0.20 TYP OR
0.35 s 45o CHAMFER
23 24
PIN 1
TOP MARK
(NOTE 6)
0.40 p 0.10
1
2
2.45 p 0.10
(4-SIDES)
(UF24) QFN 0105
0.200 REF
0.00 – 0.05
0.25 p 0.05
0.50 BSC
NOTE:
1. DRAWING PROPOSED TO BE MADE A JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGD-X)—TO BE APPROVED
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE, IF PRESENT
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON THE TOP AND BOTTOM OF PACKAGE
4066fc
26
LTC4066/LTC4066-1
PACKAGE DESCRIPTION
PF Package
24-Lead Plastic UTQFN (4mm × 4mm)
(Reference LTC DWG # 05-08-1748 Rev Ø)
0.70 p0.05
2.45 p 0.05
2.50 REF
4.50 p 0.05
3.10 p 0.05
2.45 p 0.05
PACKAGE OUTLINE
0.25 p0.05
0.50 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
BOTTOM VIEW—EXPOSED PAD
0.55 p 0.05
4.00 p 0.10
R = 0.05
TYP
R = 0.115
TYP
23 24
PIN 1
TOP MARK
(NOTE 6)
0.40 p 0.10
1
2.45 p 0.10
4.00 p 0.10
PIN 1 NOTCH
R = 0.20 TYP
OR 0.35 s 45o
CHAMFER
2
2.50 REF
2.45 p 0.10
(PF24) UTQFN 0107
0.125 REF
0.00 – 0.05
0.25 p 0.05
0.50 BSC
NOTE:
1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE, IF PRESENT
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON THE TOP AND BOTTOM OF PACKAGE
4066fc
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
27
LTC4066/LTC4066-1
TYPICAL APPLICATION
USB Power Control Application with Wall Adapter Input
5V WALL
ADAPTER
INPUT
4.7μF
10k
510Ω
TO LDOs
REGs, ETC
4.7μF
510Ω
1Ω*
5V (NOM)
FROM USB
CABLE VBUS
IN
4.7μF
R1
26.7k
1Ω*
CHRG
OUT
BAT
ACPR
VNTC
WALL
+
RNTCBIAS
100k
Li-Ion
CELL
NTC
R2
10k
RNTC
100k
LTC4066
SHUTDOWN
SHDN
SUSPEND USB POWER
SUSP
POL
500mA/100mA SELECT
HPWR
ISTAT
INPUT CURRENT
LIMIT DISABLE
CLDIS
PROG
*SERIES 1Ω RESISTOR ONLY
NEEDED FOR INDUCTIVE
INPUT SUPPLIES
TO ADC FOR
GAS GAUGE
TIMER
CLPROG
RPROG
71.5k
GND
RCLPROG
2.1k
0.15μF
RISTAT
2k
4006 TA03
RELATED PARTS
PART NUMBER
Battery Chargers
LTC1733
LTC1734
DESCRIPTION
COMMENTS
Monolithic Lithium-Ion Linear Battery Charger
Standalone Charger with Programmable Timer, Up to 1.5A Charge Current
Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed
LTC4057
LTC4058
LTC4059
Lithium-Ion Linear Battery Charger in ThinSOT™
Lithium-Ion Linear Battery Charger in ThinSOT
Switch Mode Lithium-Ion Battery Charger
Monolithic Lithium-Ion Battery Pulse Charger
USB Compatible Monolithic Li-Ion Battery Charger
Standalone Linear Li-Ion Battery Charger with
Integrated Pass Transistor in ThinSOT
Lithium-Ion Linear Battery Charger
Standalone 950mA Lithium-Ion Charger in DFN
900mA Linear Lithium-Ion Battery Charger
LTC4411/LTC4412
Low Loss PowerPath Controller in ThinSOT
LTC1734L
LTC4002
LTC4052
LTC4053
LTC4054
Power Management
LTC3405/LTC3405A 300mA (IOUT), 1.5MHz, Synchronous Step-Down
DC/DC Converters
LTC3406/LTC3406A 600mA (IOUT), 1.5MHz, Synchronous Step-Down
DC/DC Converters
LTC3411
1.25A (IOUT), 4MHz, Synchronous Step-Down
DC/DC Converter
LTC3440
600mA (IOUT), 2MHz, Synchronous Buck-Boost
DC/DC Converter
LTC3455
Dual DC/DC Converter with USB Power Manager and
Li-Ion Battery Charger
LTC4055
USB Power Controller and Battery Charger
Low Current Version of LTC1734; 50mA ≤ ICHRG ≤ 180mA
Standalone, 4.7V ≤ VIN ≤ 24V, 500kHz Frequency, 3-Hour Charge Termination
No Blocking Diode or External Power FET Required, ≤1.5A Charge Current
Standalone Charger with Programmable Timer, Up to 1.25A Charge Current
Thermal Regulation Prevents Overheating, C/10 Termination, C/10 Indicator,
Up to 800mA Charge Current
Up to 800mA Charge Current, Thermal Regulation, ThinSOT Package
C/10 Charge Termination, Battery Kelvin Sensing, ±7% Charge Accuracy
2mm × 2mm DFN Package, Thermal Regulation, Charge Current Monitor
Output
Automatic Switching Between DC Sources, Load Sharing, Replaces ORing
Diodes
95% Efficiency, VIN = 2.7V to 6V, VOUT = 0.8V, IQ = 20μA, ISD < 1μA,
ThinSOT Package
95% Efficiency, VIN = 2.5V to 5.5V, VOUT = 0.6V, IQ = 20μA, ISD < 1μA,
ThinSOT Package
95% Efficiency, VIN = 2.5V to 5.5V, VOUT = 0.8V, IQ = 60μA, ISD < 1μA,
MS10 Package
95% Efficiency, VIN = 2.5V to 5.5V, VOUT = 2.5V, IQ = 25μA, ISD < 1μA,
MS Package
Seamless Transition Between Power Sources: USB, Wall Adapter and Battery;
95% Efficient DC/DC Conversion
Charges Single Cell Li-Ion Batteries Directly from a USB Port, Thermal
Regulation, 200mΩ Ideal Diode, 4mm × 4mm QFN16 Package
ThinSOT is a trademark of Linear Technology Corporation.
4066fc
28 Linear Technology Corporation
LT 0108 REV C • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2005