FEATURES
POWER MANAGER
n
High Efficiency Switching PowerPath
TM
Controller
with Bat-Track
TM
Adaptive Output Control
n
Programmable USB or Wall Current Limit
(100mA/500mA/1A)
n
Full Featured Li-Ion/Polymer Battery Charger
n
Instant-On Operation with a Discharged Battery
n
1.5A Maximum Charge Current
n
Internal 180mΩ Ideal Diode Plus External Ideal Diode
Controller Powers Load in Battery Mode
n
Low No-Load I when Powered from BAT (<30μA)
Q
DC/DCs
n
Dual High Efficiency Buck DC/DCs (400mA/400mA I
OUT
)
n
High Efficiency Buck-Boost DC/DC (1A I
OUT
)
n
All Regulators Operate at 2.25MHz
n
Dynamic Voltage Scaling on Two Buck Outputs
n
I
2
C Control of Enables, Mode, Two V
OUT
Settings
n
ENALL Pin with Power-Up Sequence Control
n
Low No-Load Quiescent Current: 20μA Each
LTC3556
High Efficiency USB Power
Manager with Dual Buck
and Buck-Boost DC/DCs
DESCRIPTION
The LTC
®
3556 is a highly integrated power management
and battery charger IC for Li-Ion/Polymer battery applica-
tions. It includes a high efficiency current limited switching
PowerPath manager with automatic load prioritization, a
battery charger, an ideal diode, and three synchronous
switching regulators (two bucks and one buck-boost).
Designed specifically for USB applications, the LTC3556’s
switching power manager automatically limits input cur-
rent to a maximum of either 100mA or 500mA for USB
applications or 1A for adapter-powered applications.
The LTC3556’s switching input stage transmits nearly all of
the 2.5W available from the USB port to the system load
with minimal power wasted as heat. This feature allows
the LTC3556 to provide more power to the application and
eases the constraint of thermal budgeting in small spaces.
The two buck regulators can provide up to 400mA each
and the buck-boost can deliver 1A.
The LTC3556 is available in the low profile 28-pin (4mm
×
5mm
×
0.75mm) QFN surface mount package.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation. PowerPath
and Bat-Track are trademarks of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Protected by U.S. Patents including 6522118 and 6404251.
APPLICATIONS
n
n
HDD-Based MP3 Players, PDAs, GPS, PMPs
Other USB-Based Handheld Products
TYPICAL APPLICATION
High Efficiency PowerPath Manager, Dual Buck, Buck-Boost and LDO
USB/WALL
4.5V TO 5.5V
USB COMPLIANT
STEP-DOWN
REGULATOR
CC/CV
BATTERY
CHARGER
CHARGE
T
LTC3556
ALWAYS ON LDO
ENALL
SEQ
I
2
C
3
DUAL HIGH EFFICIENCY
BUCKS
HIGH EFFICIENCY
BUCK-BOOST
I
2
C PORT
1
2
3
3.3V/25mA
0.8V TO 3.6V/400mA
0.8V TO 3.6V/400mA
RTC/LOW
POWER LOGIC
MEMORY
CORE
μP
0V
OPTIONAL
TO OTHER
LOADS
700
600
CHARGE CURRENT (mA)
500
400
300
200
100
0
2.8
3
V
BUS
= 5V
5X MODE
BATTERY CHARGER PROGRAMMED FOR 1A
3.2 3.4 3.6
3.8
BATTERY VOLTAGE (V)
4
4.2
Battery Charge Current
vs Battery Voltage
BATTERY CHARGE CURRENT
EXTRA CURRENT
FOR FASTER CHARGING
500mA USB CURRENT LIMIT
+
Li-Ion
2.5V to 3.3V/1A
PGOODALL
HDD/IO
3556 TA01
3556 TA01b
3556f
1
LTC3556
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
ENALL
TOP VIEW
V
BUS
V
OUT
SCL
SEQ
BAT
22 GATE
21 CHRG
20 PROG
29
19 SW2
18 V
IN2
17 FB2
16 SDA
15 PGOODALL
9 10 11 12 13 14
SWAB3
DV
CC
V
IN3
SWCD3
V
OUT3
SW
V
BUS
(Transient) t < 1ms, Duty Cycle < 1% .. –0.3V to 7V
V
IN1
, V
IN2
, V
IN3
, V
BUS
(Static), DV
CC
,
FB1, FB2, NTC, BAT, ENALL, SCL, SDA,
PGOODALL,
CHRG
....................................... –0.3V to 6V
SEQ ....................–0.3V to Lesser of 6V or (V
OUT
+ 0.3V)
FB3, V
C3
.............. –0.3V to Lesser of 6V or (V
IN3
+ 0.3V)
I
CLPROG
....................................................................3mA
I
PGOODALL
, I
CHRG
....................................................50mA
I
PROG
........................................................................2mA
I
LDO3V3
...................................................................30mA
I
SW1
, I
SW2
............................................................600mA
I
SW
, I
BAT
, I
VOUT
.............................................................2A
I
SWAB3
, I
SWCD3
, I
VOUT3
.............................................2.5A
Operating Temperature Range (Note 2).... –40°C to 85°C
Junction Temperature (Note 3) ............................. 125°C
Storage Temperature Range................... –65°C to 125°C
28 27 26 25 24 23
LDO3V3 1
CLPROG 2
NTC 3
SW1 4
V
IN1
5
FB1 6
FB3 7
V
C3
8
UFD PACKAGE
28-LEAD (4mm 5mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 37°C/W
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3556EUFD#PBF
TAPE AND REEL
LTC3556EUFD#TRPBF
PART MARKING
3556
PACKAGE DESCRIPTION
28-Lead (4mm
×
5mm) Plastic QFN
TEMPERATURE RANGE
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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/
ELECTRICAL CHARACTERISTICS
SYMBOL
V
BUS
I
BUSLIM
PARAMETER
Input Supply Voltage
Total Input Current
PowerPath Switching Regulator
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, V
IN1
= V
IN2
= V
IN3
= V
OUT3
= 3.8V, BAT = 3.8V, DV
CC
= 3.3V,
R
PROG
= 1k, R
CLPROG
= 3.01k, unless otherwise noted.
CONDITIONS
MIN
4.35
1x Mode, V
OUT
= BAT
5x Mode, V
OUT
= BAT
10x Mode, V
OUT
= BAT
Suspend Mode, V
OUT
= BAT
1x Mode, I
OUT
= 0mA
5x Mode, I
OUT
= 0mA
10x Mode, I
OUT
= 0mA
Suspend Mode, I
OUT
= 0mA
1x Mode
5x Mode
10x Mode
Suspend Mode
l
l
l
l
TYP
MAX
5.5
UNITS
V
mA
mA
mA
mA
mA
mA
mA
mA
mA/mA
mA/mA
mA/mA
mA/mA
3556f
87
436
800
0.31
95
460
860
0.38
7
15
15
0.044
224
1133
2140
11.3
100
500
1000
0.50
I
VBUSQ
V
BUS
Quiescent Current
h
CLPROG
(Note 4)
Ratio of Measured V
BUS
Current to
CLPROG Program Current
2
LTC3556
ELECTRICAL CHARACTERISTICS
SYMBOL
I
OUT(POWERPATH)
PARAMETER
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, V
IN1
= V
IN2
= V
IN3
= V
OUT3
= 3.8V, BAT = 3.8V, DV
CC
= 3.3V,
R
PROG
= 1k, R
CLPROG
= 3.01k, unless otherwise noted.
CONDITIONS
MIN
TYP
135
672
1251
0.32
1.188
100
3.95
4.30
4.00
200
50
3.4
4.5
l
MAX
UNITS
mA
mA
mA
mA
V
mV
V
OUT
Current Available Before Loading 1x Mode, BAT = 3.3V
BAT
5x Mode, BAT = 3.3V
10x Mode, BAT = 3.3V
Suspend Mode
CLPROG Servo Voltage in Current
Limit
V
BUS
Undervoltage Lockout
V
BUS
to BAT Differential Undervoltage
Lockout
V
OUT
Voltage
1x, 5x, 10x Modes
Suspend Mode
Rising Threshold
Falling Threshold
Rising Threshold
Falling Threshold
1x, 5x, 10x Modes, 0V < BAT < 4.2V,
I
OUT
= 0mA, Battery Charger Off
USB Suspend Mode, I
OUT
= 250μA
V
CLPROG
V
UVLO_VBUS
V
UVLO_VBUS-BAT
V
OUT
4.35
V
V
mV
mV
BAT +
0.3
4.6
2.25
0.18
0.30
4.7
4.7
2.7
V
V
MHz
Ω
Ω
A
A
f
OSC
Switching Frequency
1.8
R
PMOS_POWERPATH
PMOS On-Resistance
R
NMOS_POWERPATH
NMOS On-Resistance
I
PEAK_POWERPATH
Battery Charger
V
FLOAT
I
CHG
I
BAT
V
PROG
V
PROG_TRKL
V
C/10
h
PROG
I
TRKL
V
TRKL
ΔV
TRKL
V
RECHRG
t
TERM
t
BADBAT
h
C/10
V
CHRG
I
CHRG
R
ON_CHG
T
LIM
BAT Regulated Output Voltage
Constant Current Mode Charge
Current
Battery Drain Current
PROG Pin Servo Voltage
PROG Pin Servo Voltage in Trickle
Charge
C/10 Threshold Voltage at PROG
Ratio of I
BAT
to PROG Pin Current
Trickle Charge Current
Trickle Charge Threshold Voltage
Trickle Charge Hysteresis Voltage
Recharge Battery Threshold Voltage
Safety Timer Termination
Bad Battery Termination Time
CHRG
Pin Output Low Voltage
CHRG
Pin Leakage Current
Battery Charger Power FET
On-Resistance (Between V
OUT
and BAT)
Junction Temperature in Constant
Temperature Mode
Threshold Voltage Relative to V
FLOAT
Timer Starts When BAT = V
FLOAT
BAT < V
TRKL
I
CHRG
= 5mA
V
CHRG
= 5V
–75
3.3
0.42
0.088
BAT < V
TRKL
BAT Rising
2.7
BAT < V
TRKL
l
Peak Switch Current Limit
1x, 5x Modes
10x Mode
4.179
4.165
980
185
2
2
3
4.200
4.200
1022
204
3.5
27
1.000
0.100
100
1022
100
2.85
135
–100
4
0.5
0.1
65
0.18
110
–125
5
0.63
0.112
100
1
3.0
4.221
4.235
1065
223
5
38
V
V
mA
mA
μA
μA
V
V
mV
mA/mA
mA
V
mV
mV
Hour
Hour
mA/mA
mV
μA
Ω
°C
R
PROG
= 5k
V
BUS
> V
UVLO
, Battery Charger Off, I
OUT
= 0μA
V
BUS
= 0V, I
OUT
= 0μA (Ideal Diode Mode)
End of Charge Indication Current Ratio (Note 5)
3556f
3
LTC3556
ELECTRICAL CHARACTERISTICS
SYMBOL
NTC
V
COLD
V
HOT
V
DIS
I
NTC
Ideal Diode
V
FWD
R
DROPOUT
I
MAX_DIODE
V
LDO3V3
R
CL_LDO3V3
R
OL_LDO3V3
V
IL
V
IH
R
PD
V
OL
I
OH
t
PGOODALL
I
2
C Port (Note 9)
DV
CC
I
DVCC
V
DVCC_UVLO
ADDRESS
V
IH
SDA, SCL
V
IL
SDA, SCL
I
IH
, I
IL
SDA, SCL
V
OL
SDA
f
SCL
t
BUF
t
HD_STA
t
SU_STA
t
SU_STO
t
HD_DAT(O)
Input Supply Voltage
DV
CC
Current
DV
CC
UVLO
I
2
C Address
Input High Voltage
Input Low Voltage
Input High/Low Current
SDA Output Low Voltage
Clock Operating Frequency
Bus Free Time Between Stop and Start
Condition
Hold Time After (Repeated) Start
Condition
Repeated Start Condition Setup Time
Stop Condition Setup Time
Data Hold Time Output
1.3
0.6
0.6
0.6
0
900
I
SDA
= 3mA
70
30
–1
0
1
0.4
400
SCL/SDA = 0kHz
1.6
0.3
1.0
0001 001[0]
%DV
CC
%DV
CC
μA
V
kHz
μs
μs
μs
μs
ns
3556f
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, V
IN1
= V
IN2
= V
IN3
= V
OUT3
= 3.8V, BAT = 3.8V, DV
CC
= 3.3V,
R
PROG
= 1k, R
CLPROG
= 3.01k, unless otherwise noted.
PARAMETER
Cold Temperature Fault Threshold
Voltage
Hot Temperature Fault Threshold
Voltage
NTC Disable Threshold Voltage
NTC Leakage Current
Forward Voltage
CONDITIONS
Rising Threshold
Hysteresis
Falling Threshold
Hysteresis
Falling Threshold
Hysteresis
V
NTC
= V
BUS
= 5V
V
BUS
= 0V, I
OUT
= 10mA
I
OUT
= 10mA
1.6
0mA < I
LDO3V3
< 25mA
3.1
3.3
4
23
ENALL Pin
ENALL Pin
ENALL Pin
PGOODALL Pin, I
PULL-UP
= 5mA
PGOODALL Pin, V
PGOODALL
= 5V
230
5.5
1
1.2
4.5
0.07
0.2
1
0.4
3.5
MIN
75.0
33.4
0.7
–50
2
15
0.18
TYP
76.5
1.5
34.9
1.5
1.7
50
MAX
78.0
36.4
2.7
50
UNITS
%V
BUS
%V
BUS
%V
BUS
%V
BUS
%V
BUS
mV
nA
mV
mV
Ω
A
V
Ω
Ω
V
V
MΩ
V
μA
ms
V
μA
V
Internal Diode On-Resistance, Dropout V
BUS
= 0V
Internal Diode Current Limit
Regulated Output Voltage
Closed-Loop Output Resistance
Dropout Output Resistance
Logic Low Input Voltage
Logic High Input Voltage
Pull-Down Resistance
Logic Low Output Voltage
Logic High Leakage Current
PGOODALL Assertion Delay
Always On 3.3V Supply
Logic (ENALL, PGOODALL)
4
LTC3556
ELECTRICAL CHARACTERISTICS
SYMBOL
t
HD_DAT(I)
t
SU_DAT
t
LOW
t
HIGH
t
f
t
r
t
SP
V
IN1,2,3
V
OUTUVLO
PARAMETER
Data Hold Time Input
Data Setup Time
SCL Clock Low Period
SCL Clock High Period
Clock/Data Fall Time
Clock/Data Rise Time
Input Spike Suppression Pulse Width
Input Supply Voltage
V
OUT
UVLO—V
OUT
Falling
V
OUT
UVLO—V
OUT
Rising
Oscillator Frequency
Pulse Skip Mode Input Current
Burst Mode
®
Input Current
Forced Burst Mode Input Current
LDO Mode Input Current
Shutdown Input Current
PMOS Switch Current Limit
Available Output Current
I
OUT1
= 0μA (Note 6)
I
OUT1
= 0μA (Note 6)
I
OUT1
= 0μA (Note 6)
I
OUT1
= 0μA (Note 6)
I
OUT1
= 0μA, FB1 = 0V
Pulse Skip/Burst Mode Operation
Pulse Skip/Burst Mode Operation (Note 9)
Forced Burst Mode Operation (Note 9)
LDO Mode (Note 9)
Full Scale (1, 1, 1, 1) (Note 7)
Zero Scale (0, 0, 0, 0) (Note 7)
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, V
IN1
= V
IN2
= V
IN3
= V
OUT3
= 3.8V, BAT = 3.8V, DV
CC
= 3.3V,
R
PROG
= 1k, R
CLPROG
= 3.01k, unless otherwise noted.
CONDITIONS
MIN
0
100
1.3
0.6
C
B
= Capacitance of One BUS Line (pF)
C
B
= Capacitance of One BUS Line (pF)
20 + 0.1C
B
20 + 0.1C
B
300
300
50
2.7
V
IN1,2,3
Connected to V
OUT
Through Low
Impedance. Switching Regulators are
Disabled in UVLO
l
TYP
MAX
UNITS
ns
ns
μs
μs
ns
ns
ns
V
V
V
MHz
μA
μA
μA
μA
μA
mA
mA
mA
mA
Switching Regulators 1, 2 and 3
5.5
2.6
2.8
2.25
225
35
20
20
600
400
60
50
0.780
0.405
0.800
0.425
25
0.6
0.7
0.25
(Note 8)
V
FB1
= 0.85V
l
2.5
2.9
2.7
400
60
35
35
1
1100
f
OSC
I
VIN1
1.8
Switching Regulator 1 (Buck)
I
LIM1
I
OUT1
800
V
FBHIGH1
V
FBLOW1
V
LSB1
R
P1
R
N1
R
LDO_CL1
R
LDO_OL1
I
FB1
D1
R
SW1
I
VIN2
Maximum Servo Voltage
Minimum Servo Voltage
V
FB1
Servo Voltage Step Size
PMOS R
DS(ON)
NMOS R
DS(ON)
LDO Mode Closed-Loop R
OUT
LDO Mode Open-Loop R
OUT
FB1 Input Current
Maximum Duty Cycle
SW1 Pull-Down in Shutdown
Pulse Skip Mode Input Current
Burst Mode Input Current
Forced Burst Mode Input Current
LDO Mode Input Current
Shutdown Input Current
PMOS Switch Current Limit
Available Output Current
0.820
0.445
V
V
mV
Ω
Ω
Ω
Ω
2.5
–50
100
10
50
nA
%
kΩ
Switching Regulator 2 (Buck)
I
OUT2
= 0μA (Note 6)
I
OUT2
= 0μA (Note 6)
I
OUT2
= 0μA (Note 6)
I
OUT2
= 0μA (Note 6)
I
OUT2
= 0μA, FB2 = 0V
Pulse Skip/Burst Mode Operation
Pulse Skip/Burst Mode Operation (Note 9)
Forced Burst Mode Operation (Note 9)
LDO Mode (Note 9)
600
400
60
50
225
35
20
20
800
400
60
35
35
1
1100
μA
μA
μA
μA
μA
mA
mA
mA
mA
3556f
I
LIM2
I
OUT2
Burst Mode is a registered trademark of Linear Technology Corporation.
5
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