LTC3557/LTC3557-1
USB Power Manager with
Li-Ion Charger and Three
Step-Down Regulators
FEATURES
■
DESCRIPTION
The LTC
®
3557/LTC3557-1 is a highly integrated power
management and battery charger IC for single cell Li-Ion/
Polymer battery applications. It includes a PowerPath
TM
manager with automatic load prioritization, a battery
charger, an ideal diode and numerous internal protection
features. Designed specifically for USB applications, the
LTC3557/LTC3557-1 power manager automatically limits
input current to a maximum of either 100mA or 500mA
for USB applications or 1A for wall adapter powered
applications. 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. The LTC3557/LTC3557-1 also includes three
adjustable synchronous step-down switching regulators
and a high voltage buck regulator output controller with
Bat-Track that allows efficient charging from supplies as
high as 38V. The LTC3557/LTC3557-1 is available in a low
profile 4mm
×
4mm
×
0.75mm 28-pin QFN package.
, LT LTC, LTM and Burst Mode are registered trademarks of Linear Technology
,
Corporation. Bat-Track and PowerPath are trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 6522118, 6700364. Other patents pending.
■
■
■
■
■
■
■
Seamless Transition Between Input Power Sources:
Li-Ion Battery, USB, 5V Wall Adapter or High
Voltage Buck Regulator with Bat-Track
TM
200mΩ Internal Ideal Diode Plus Optional External
Ideal Diode Controller Provides Low Loss Power
Path When Input Current is Limited or Unavailable
Triple Adjustable High Efficiency Step-Down
Switching Regulators (600mA, 400mA, 400mA I
OUT
)
Pin Selectable Burst Mode
®
Operation
Full Featured Li-Ion/Polymer Battery Charger
1.5A Maximum Charge Current with Thermal Limiting
Battery Float Voltage:
4.2V (LTC3557)
4.1V (LTC3557-1)
Low Profile 4mm
×
4mm 28-Pin QFN Package
APPLICATIONS
■
■
■
HDD-Based MP3 Players
PDA, PMP PND/GPS
,
USB-Based Handheld Products
TYPICAL APPLICATION
HV SUPPLY
8V TO 38V
(TRANSIENTS
TO 60V)
Input and Battery Current vs Load Current
HIGH VOLTAGE
BUCK DC/DC
600
500
400
0V
CURRENT (mA)
V
OUT
CC/CV
CHARGER
LTC3557/LTC3557-1
ALWAYS ON LDO
TRIPLE HIGH EFFICIENCY
STEP-DOWN
SWITCHING REGULATORS
35571 TA01a
R
PROG
= 2k
R
CLPROG
= 2k
I
IN
100mA/500mA
1000mA
USB OR
5V ADAPTER
I
LOAD
300
200
100
0
–100
0
WALL = 0V
100
200
I
BAT
(DISCHARGING)
400
300
I
LOAD
(mA)
500
600
I
BAT
(CHARGING)
CHARGE
+
NTC
SINGLE CELL
Li-Ion
3.3V/25mA
0.8V to 3.6V/600mA
0.8V to 3.6V/400mA
0.8V to 3.6V/400mA
RST
35571 TA01b
35571fc
1
LTC3557/LTC3557-1
ABSOLUTE MAXIMUM RATINGS
(Notes 1-4)
PIN CONFIGURATION
CLPROG
TOP VIEW
ACPR
V
BUS
V
OUT
FB2
BAT
21 GATE
20 PROG
19 NTC
29
18 V
NTC
17 SW3
16 V
IN2
15 SW2
8
MODE
9 10 11 12 13 14
EN1
EN2
EN3
RST2
FB3
V
C
CHRG
ILIM0 1
ILIM1 2
WALL 3
LDO3V3 4
SW1 5
V
IN1
6
FB1 7
V
BUS
, V
OUT
, V
IN1
, V
IN2
t < 1ms and Duty Cycle < 1% ..................
−0.3V
to 7V
Steady State .............................................
−0.3V
to 6V
BAT, NTC,
CHRG,
WALL, V
C
,
MODE, FB1, FB2, FB3,
RST2
........................
−0.3V
to 6V
EN1, EN2, EN3 ..............................
−0.3V
to V
OUT
+
0.3V
ILIM0, ILIM1, PROG .......................
−0.3V
to V
CC
+
0.3V
I
VBUS
, I
VOUT
, I
BAT
.........................................................2A
I
SW1
.....................................................................850mA
I
SW2
, I
SW3
............................................................600mA
I
RST2
, I
CHRG
, I
ACPR
.................................................75mA
I
CLPROG
, I
PROG
..........................................................2mA
Maximum Operating Junction Temperature .......... 110°C
Operating Ambient Temperature Range ...
−40°C
to 85°C
Storage Temperature Range...................
−65°C
to 125°C
28 27 26 25 24 23 22
UF PACKAGE
28-LEAD (4mm 4mm) PLASTIC QFN
T
JMAX
= 110°C,
θ
JA
= 37°C/W
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3557EUF#PBF
LTC3557EUF-1#PBF
TAPE AND REEL
LTC3557EUF#TRPBF
LTC3557EUF-1#TRPBF
PART MARKING
3557
35571
PACKAGE DESCRIPTION
28-Lead (4mm
×
4mm) Plastic QFN
28-Lead (4mm
×
4mm) Plastic QFN
TEMPERATURE RANGE
−40°C
to 85°C
−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/
POWER MANAGER ELECTRICAL CHARACTERISTICS
The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
BUS
= 5V, V
BAT
= 3.8V, ILIM0 = ILIM1 = 5V, WALL = EN1 = EN2 = EN3 = 0V, R
PROG
= 2k, R
CLPROG
= 2.1k.
SYMBOL
V
BUS
I
BUS(LIM)
PARAMETER
Input Supply Voltage
Total Input Current (Note 5)
ILIM0 = 0V, ILIM1 = 0V (1x Mode)
ILIM0 = 5V, ILIM1 = 5V (5x Mode)
ILIM0 = 5V, ILIM1 = 0V (10x Mode)
1x, 5x, 10x Modes
ILIM0 = 0V, ILIM1 = 5V (Suspend Mode)
●
●
CONDITIONS
MIN
4.35
80
450
900
TYP
MAX
5.5
UNITS
V
mA
mA
mA
mA
mA
mA/mA
V
V
V
Input Power Supply
90
475
950
0.35
0.05
1000
0.2
1.0
2.0
3.5
3.8
3.7
3.9
100
500
1000
0.1
I
BUSQ
h
CLPROG
V
CLPROG
Input Quiescent Current
Ratio of Measured V
BUS
Current to CLPROG 1x, 5x, 10x Modes
Program Current
CLPROG Servo Voltage in Current Limit
1x Mode
5x Mode
10x Mode
Rising Threshold
Falling Threshold
V
UVLO
V
BUS
Undervoltage Lockout
V
V
35571fc
2
LTC3557/LTC3557-1
POWER MANAGER ELECTRICAL CHARACTERISTICS
The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
BUS
= 5V, V
BAT
= 3.8V, ILIM0 = ILIM1 = 5V, WALL = EN1 = EN2 = EN3 = 0V, R
PROG
= 2k, R
CLPROG
= 2.1k.
SYMBOL
V
DUVLO
R
ON_LIM
PARAMETER
V
BUS
to V
OUT
Differential Undervoltage
Lockout
Input Current Limit Power FET
On-Resistance (Between V
BUS
and V
OUT
)
V
BAT
Regulated Output Voltage
LTC3557
LTC3557, 0°C ≤ T
A
≤ 85°C
LTC3557-1
LTC3557-1, 0°C ≤ T
A
≤ 85°C
R
PROG
= 1k, Input Current Limit = 2A
R
PROG
= 2k, Input Current Limit = 1A
R
PROG
= 5k, Input Current Limit = 400mA
V
BUS
> V
UVLO
, Charger Off, I
OUT
= 0μA
V
BUS
= 0V, I
OUT
= 0μA (Ideal Diode Mode)
BAT < V
TRKL
BAT < V
TRKL
BAT Rising
BAT Falling
Threshold Voltage Relative to V
FLOAT
Timer Starts when BAT = V
FLOAT
– 50mV
BAT < V
TRKL
(Note 6)
40
2.5
−75
3.2
0.4
0.085
●
●
●
CONDITIONS
Rising Threshold
Falling Threshold
MIN
TYP
50
−50
0.2
MAX
100
UNITS
mV
mV
Ω
Battery Charger
V
FLOAT
4.179
4.165
4.079
4.065
950
465
180
4.200
4.200
4.100
4.100
1000
500
200
6
55
1.000
0.100
1000
50
2.85
2.75
−100
4
0.5
0.1
200
110
60
3.0
−115
4.8
0.6
0.115
4.221
4.235
4.121
4.135
1050
535
220
27
100
V
V
V
V
mA
mA
mA
μA
μA
V
V
mA/mA
mA
V
V
mV
Hour
Hour
mA/mA
mΩ
°C
I
CHG
Constant Current Mode Charge Current
I
BAT
Battery Drain Current
PROG Pin Servo Voltage
V
PROG
V
PROG(TRKL)
PROG Pin Servo Voltage in Trickle Charge
h
PROG
I
TRKL
V
TRKL
ΔV
RECHRG
t
TERM
t
BADBAT
h
C/10
R
ON(CHG)
T
LIM
NTC
V
COLD
V
HOT
V
DIS
I
NTC
Ideal Diode
V
FWD
R
DROPOUT
I
MAX
V
LDO3V3
R
CL(LDO3V3)
Forward Voltage Detection
Diode On-Resistance, Dropout
Diode Current Limit
Regulated Output Voltage
Closed-Loop Output Resistance
Cold Temperature Fault Threshold Voltage
Hot Temperature Fault Threshold Voltage
NTC Disable Threshold Voltage
NTC Leakage Current
Ratio of I
BAT
to PROG Pin Current
Trickle Charge Current
Trickle Charge Rising Threshold
Trickle Charge Falling Threshold
Recharge Battery Threshold Voltage
Safety Timer Termination Period
Bad Battery Termination Time
End-of-Charge Indication Current Ratio
Battery Charger Power FET On-Resistance
(Between V
OUT
and BAT)
Junction Temperature in Constant
Temperature Mode
Rising NTC Voltage
Hysteresis
Falling NTC Voltage
Hysteresis
Falling NTC Voltage
Hysteresis
NTC = V
BUS
= 5V
●
75
34
1.2
−50
76
1.3
35
1.3
1.7
50
77
36
2.2
50
%V
VNTC
%V
VNTC
%V
VNTC
%V
VNTC
%V
VNTC
mV
nA
I
OUT
= 10mA
I
OUT
= 1A
(Note 7)
0mA < I
LDO3V3
< 25mA
BAT = 3.0V, V
BUS
= 0V
5
15
200
3.6
25
mV
mΩ
A
Always On 3.3V Supply
3.1
3.3
24
3.2
3.5
V
Ω
Ω
35571fc
R
OL(LDO3V3)
Open-Loop Output Resistance
3
LTC3557/LTC3557-1
POWER MANAGER ELECTRICAL CHARACTERISTICS
The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
BUS
= 5V, V
BAT
= 3.8V, ILIM0 = ILIM1 = 5V, WALL = EN1 = EN2 = EN3 = 0V, R
PROG
= 2k, R
CLPROG
= 2.1k.
SYMBOL
Wall Adapter
V
ACPR
V
W
ΔV
W
I
QWALL
ACPR
Pin Output High Voltage
ACPR
Pin Output Low Voltage
Absolute Wall Input Threshold Voltage
Differential Wall Input Threshold Voltage
Wall Operating Quiescent Current
I
ACPR
= 1mA
I
ACPR
= 1mA
WALL Rising
WALL Falling
WALL
−
BAT Falling
WALL
−
BAT Rising
I
WALL
+
I
VOUT
, I
BAT
= 0mA,
WALL = V
OUT
= 5V
ILIM0, ILIM1
ILIM0, ILIM1
ILIM0, ILIM1; V
PIN
= 1V
I
CHRG
= 10mA
BAT = 4.5V,
CHRG
= 5V
1.2
2
0.15
0
0.4
1
V
OUT
−
0.3
V
OUT
0
4.3
3.2
25
75
440
0.3
4.45
V
V
V
V
mV
mV
μA
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
3.1
0
150
Logic (I
LIM0
, I
LIM1
and
CHRG)
V
IL
V
IH
I
PD
V
CHRG
I
CHRG
Input Low Voltage
Input High Voltage
Static Pull-Down Current
CHRG
Pin Output Low Voltage
CHRG
Pin Input Current
0.4
V
V
μA
V
μA
SWITCHING REGULATOR ELECTRICAL CHARACTERISTICS
The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
OUT
= V
IN1
= V
IN2
= 3.8V, MODE = EN1 = EN2 = EN3 = 0V.
SYMBOL
V
IN1
, V
IN2
V
OUT
UVL0
PARAMETER
Input Supply Voltage
V
OUT
Falling
V
OUT
Rising
Oscillator Frequency
Input Low Voltage
Input High Voltage
Static Pull-Down Current
Pulse-Skip Mode Input Current (Note 10)
Burst Mode Input Current (Note 10)
Shutdown Input Current
I
LIM1
V
FB1
I
FB1
D1
R
P1
R
N1
R
SW1(PD)
Peak PMOS Current Limit
Feedback Voltage
FB1 Input Current (Note 10)
Maximum Duty Cycle
R
DS(ON)
of PMOS
R
DS(ON)
of NMOS
SW1 Pull-Down in Shutdown
MODE, EN1, EN2, EN3
MODE, EN1, EN2, EN3
MODE, EN1, EN2, EN3 (V
PIN
= 1V)
I
OUT
= 0, EN1 = 3.8V, MODE = 0V
I
OUT
= 0, EN1 = MODE = 3.8V
I
OUT
= 0, EN1 = 0V, FB1 = 0V
EN1 = 3.8V, MODE = 0V or 3.8V (Note 7)
EN1 = 3.8V, MODE = 0V
EN1 = MODE = 3.8V
EN1 = 3.8V
FB1 = 0V, EN1 = 3.8V
EN1 = 3.8V
EN1 = 3.8V
EN1 = 0V
●
●
CONDITIONS
(Note 9)
V
IN1
and V
IN2
Connected to V
OUT
Through Low
Impedance. Switching Regulators are Disabled
Below V
OUT
UVLO
●
MIN
2.7
2.5
TYP
MAX
5.5
UNITS
V
V
V
MHz
V
V
μA
μA
Step-Down Switching Regulators 1, 2 and 3
2.7
2.8
2.25
2.9
2.59
0.4
f
OSC
V
IL
V
IH
I
PD
I
VIN1
1.91
1.2
1
220
35
0.01
900
0.78
0.78
−0.05
100
0.3
0.4
10
1200
0.8
0.8
50
1
1500
0.82
0.824
0.05
Step-Down Switching Regulator 1
μA
μA
mA
V
V
μA
%
Ω
Ω
kΩ
35571fc
4
LTC3557/LTC3557-1
SWITCHING REGULATOR ELECTRICAL CHARACTERISTICS
The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
OUT
= V
IN1
= V
IN2
= 3.8V, MODE = EN1 = EN2 = EN3 = 0V.
SYMBOL
I
VIN2
PARAMETER
Pulse-Skip Mode Input Current (Note 10)
Burst Mode Input Current (Note 10)
Shutdown Input Current
I
LIM2
V
FB2
I
FB2
D2
R
P2
R
N2
R
SW2(PD)
V
RST2
I
RST2
V
TH(RST2)
t
RST2
I
VIN2
Peak PMOS Current Limit
Feedback Voltage
FB2 Input Current (Note 10)
Maximum Duty Cycle
R
DS(ON)
of PMOS
R
DS(0N)
of NMOS
SW2 Pull-Down in Shutdown
Power-On
RST2
Pin Output Low Voltage
Power-On
RST2
Pin Threshold
Power-On
RST2
Pin Delay
Pulse-Skip Mode Input Current (Note 10)
Burst Mode Input Current (Note 10)
Shutdown Input current
I
LIM3
V
FB3
I
FB3
D3
R
P3
R
N3
R
SW3(PD)
Peak PMOS Current Limt
Feedback Voltage
FB3 Input Current (Note 10)
Maximum Duty Cycle
R
DS(ON)
of PMOS
R
DS(ON)
of NMOS
SW3 Pull-Down in Shutdown
CONDITIONS
I
OUT
= 0, EN2 = 3.8V, MODE = 0V
I
OUT
= 0, EN2 = MODE = 3.8V
I
OUT
= 0, EN2 = 0V, FB2 = 0V
EN2 = 3.8V, MODE = 0V or 3.8V (Note 7)
EN2 = 3.8V, MODE = 0V
EN2 = MODE = 3.8V
EN2 = 3.8V
FB2 = 0V, EN2 = 3.8V
EN2 = 3.8V
EN2 = 3.8V
EN2 = 0V
I
RST2
= 1mA, FB2 = 0V, EN2 = 3.8V
(Note 8)
From
RST2
Threshold to
RST2
Hi-Z
I
OUT
= 0, EN3 = 3.8V, MODE = 0V
I
OUT
= 0, EN3 = MODE = 3.8V
I
OUT
= 0, EN3 = 0V, FB3 = 0V
EN3 = 3.8V, MODE = 0V or 3.8V (Note 7)
EN3 = 3.8V, MODE = 0V
EN3 = MODE = 3.8V
EN3 = 3.8V
FB3 = 0V, EN3 = 3.8V
EN3 = 3.8V
EN3 = 3.8V
EN3 = 0V
●
●
●
●
MIN
TYP
220
35
0.01
MAX
UNITS
μA
Step-Down Switching Regulator 2
50
1
1000
0.82
0.824
0.05
0.6
0.6
10
0.1
−8
230
220
35
0.01
600
0.78
0.78
−0.05
100
0.6
0.6
10
800
0.8
0.8
50
1
1000
0.82
0.824
0.05
0.35
1
μA
μA
mA
V
V
μA
%
Ω
Ω
kΩ
V
μA
%
ms
μA
μA
μA
mA
V
V
μA
%
Ω
Ω
kΩ
600
0.78
0.78
−0.05
100
800
0.8
0.8
Power-On
RST2
Pin Input Current (Note 10) V
RST2
= 5.5V, EN2 = 3.8V
Step-Down Switching Regulator 3
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.
The LTC3557/LTC3557-1 is guaranteed to meet performance
specifications from 0°C to 85°C. Specifications over the
−40°C
to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 3.
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperatures will exceed 110°C when overtemperature protection is
active. Continuous operation above the specified maximum operating
junction temperature may result in device degradation or failure.
Note 4.
V
CC
is the greater of V
BUS
, V
OUT
or BAT.
Note 5.
Total input current is the sum of quiescent current, I
BUSQ
, and
measured current given by V
CLPROG
/R
CLPROG
• (h
CLPROG
+
1)
Note 6.
h
C/10
is expressed as a fraction of measured full charge current
with indicated PROG resistor.
Note 7.
The current limit features of this part are intended to protect the
IC from short term or intermittent fault conditions. Continuous operation
above the maximum specified pin current rating may result in device
degradation or failure.
Note 8.
RST2
threshold is expressed as a percentage difference from the
FB2 regulation voltage. The threshold is measured for FB2 rising.
Note 9.
V
OUT
not in UVLO.
Note 10.
FB high, not switching.
35571fc
5
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