FEATURES
POWER MANAGER
■
High Efficiency Switching PowerPath
TM
Controller
with Bat-Track
TM
Adaptive Output Control
■
Programmable USB or Wall Current Limit
(100mA/500mA/1A)
■
Full Featured Li-Ion/Polymer Battery Charger
■
1.5A Maximum Charge Current
■
Internal 180mΩ Ideal Diode + External Ideal Diode
Controller Powers Load in Battery Mode
■
Low No-Load Quiescent Current when Powered from
BAT (<30μA)
DC/DCs
■
Triple High Efficiency Step-Down DC/DCs
(1A/400mA/400mA I
OUT
)
■
All Regulators Operate at 2.25MHz
■
Dynamic Voltage Scaling on Two Outputs
■
I
2
C or Independent Enable, V
OUT
Controls
■
Low No-Load Quiescent Current: 20μA
■
28-Pin (4mm
×
5mm
×
0.75mm) QFN Surface
Mount Package
LTC3555
High Efficiency USB Power
Manager + Triple
Step-Down DC/DC
DESCRIPTION
The LTC
®
3555 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 general purpose
synchronous step-down switching regulators.
Designed specifically for USB applications, the LTC3555’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. Unlike
linear PowerPath controllers, the LTC3555’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 LTC3555 to provide more
power to the application and eases the constraint of thermal
budgeting in small spaces.
Two of the three general purpose switching regulators can
provide up to 400mA and the third can deliver 1A. The entire
product can be controlled via I
2
C or simple I/O.
The LTC3555 is available in the 28-pin (4mm
×
5mm
×
0.75mm) QFN surface mount package.
, 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
■
■
HDD-Based MP3 Players, PDAs, GPS, PMPs
Other USB-Based Handheld Products
TYPICAL APPLICATION
High Efficiency PowerPath Manager and Triple Step-Down Regulator
USB/WALL
4.35V TO 5.5V
USB COMPLIANT
STEP-DOWN
REGULATOR
CC/CV
BATTERY
CHARGER
CHARGE
T
LTC3555
ALWAYS ON LDO
TRIPLE
HIGH EFFICIENCY
STEP-DOWN
SWITCHING
REGULATORS
I
2
C PORT
1
2
3
3.3V/25mA
0.8V TO 3.6V/400mA
0.8V TO 3.6V/400mA
0.8V TO 3.6V/1A
RST
2
RTC/LOW
POWER LOGIC
MEMORY
I/O
CORE
μPROCESSOR
I
2
C
3555 TA01
TO OTHER
LOADS
Switching Regulator Efficiency to
System Load (P
OUT
/P
BUS
)
100
90
80
0V
OPTIONAL
EFFICIENCY (%)
70
60
50
40
30
20
10
BAT = 4.2V
BAT = 3.3V
+
Li-Ion
ENABLE
CONTROLS
5
0
0.01
V
BUS
= 5V
I
BAT
= 0mA
10x MODE
0.1
I
OUT
(A)
1
3555 TA01b
3555f
1
LTC3555
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2, 3)
PACKAGE/ORDER INFORMATION
TOP VIEW
I
LIM1
I
LIM0
V
BUS
V
OUT
EN3
BAT
22 GATE
21 CHRG
20 PROG
29
19 FB1
18 V
IN1
17 SW1
16 EN1
15 RST3
9 10 11 12 13 14
V
IN3
SW3
SDA
SCL
FB3
SW
28 27 26 25 24 23
LDO3V3 1
CLPROG 2
NTC 3
FB2 4
V
IN2
5
SW2 6
EN2 7
DV
CC
8
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, FB3, NTC, BAT, EN1, EN2, EN3,
I
LIM0
, I
LIM1
, SCL, SDA,
⎯
R
⎯
S
⎯
T
⎯
3,
⎯
C
⎯
H
⎯
R
⎯
G............ –0.3V to 6V
I
CLPROG
....................................................................3mA
I
⎯
R
⎯
S
⎯
T
⎯
3
, I
⎯
C
⎯
H
⎯
R
⎯
G
............................................................50mA
I
PROG
........................................................................2mA
I
LDO3V3
...................................................................30mA
I
SW1
, I
SW2
............................................................600mA
I
SW
, I
SW3
, I
BAT
, I
VOUT
...................................................2A
Junction Temperature ........................................... 125°C
Operating Temperature Range ................. –40°C to 85°C
Storage Temperature Range................... –65°C to 125°C
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 PART NUMBER
LTC3555EUFD
UFD PART MARKING
3555
Order Options
Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking:
http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
SYMBOL
V
BUS
I
BUSLIM
PARAMETER
Input Supply Voltage
Total Input Current
PowerPath Switching Regulator
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, BAT = 3.8V, DV
CC
= 3.3V, R
PROG
= 1k, R
CLPROG
= 3k,
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
1x Mode, BAT = 3.3V
5x Mode, BAT = 3.3V
10x Mode, BAT = 3.3V
Suspend Mode
●
●
●
●
TYP
MAX
5.5
UNITS
V
mA
mA
mA
mA
mA
mA
mA
mA
mA/mA
mA/mA
mA/mA
mA/mA
mA
mA
mA
mA
87
436
800
0.31
I
VBUSQ
V
BUS
Quiescent Current
h
CLPROG
(Note 4)
Ratio of Measured V
BUS
Current to
CLPROG Program Current
I
OUT(POWERPATH)
V
OUT
Current Available Before
Loading BAT
95
460
860
0.38
7
15
15
0.044
224
1133
2140
11.3
135
672
1251
0.32
100
500
1000
0.50
3555f
2
LTC3555
ELECTRICAL CHARACTERISTICS
SYMBOL
V
CLPROG
V
UVLO_VBUS
V
UVLO_VBUS-BAT
V
OUT
PARAMETER
CLPROG Servo Voltage in Current
Limit
V
BUS
Undervoltage Lockout
V
BUS
to BAT Differential Undervoltage
Lockout
V
OUT
Voltage
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, BAT = 3.8V, DV
CC
= 3.3V, R
PROG
= 1k, R
CLPROG
= 3k,
unless otherwise noted.
CONDITIONS
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
MIN
TYP
1.188
100
4.30
4.00
200
50
BAT + 0.3
4.6
2.25
0.18
0.30
1x, 5x Modes
10x
4.179
4.165
980
185
2
2
3
4.200
4.200
1022
204
3.5
27
1.000
0.100
100
1022
BAT < V
TRKL
BAT Rising
Threshold Voltage Relative to V
FLOAT
Timer Starts when B
AT
= V
FLOAT
BAT < V
TRKL
(Note 5)
I
⎯
C
⎯
H
⎯
R
⎯
G
= 5mA
V
⎯
C
⎯
H
⎯
R
⎯
G
= 5V
0.18
110
2.7
–75
3.3
0.42
0.088
100
2.85
135
–100
4
0.5
0.1
65
–125
5
0.63
0.112
100
1
3.0
4.221
4.235
1065
223
5
38
MAX
UNITS
V
mV
V
V
mV
mV
V
V
MHz
Ω
Ω
A
A
V
V
mA
mA
μA
μA
V
V
mV
mA/mA
mA
V
mV
mV
Hour
Hour
mA/mA
mV
μA
Ω
°C
4.35
3.95
3.4
4.5
1.8
4.7
4.7
2.7
f
OSC
Switching Frequency
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
ΔV
RECHRG
t
TERM
t
BADBAT
h
C/10
V
⎯
C
⎯
H
⎯
R
⎯
G
I
⎯
C
⎯
H
⎯
R
⎯
G
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
End of Charge Indication Currrent
Ratio
⎯
C
⎯
H
⎯
R
⎯
G Pin Output Low Voltage
⎯
C
⎯
H
⎯
R
⎯
G Pin Leakage Current
Battery Charger Power FET On
Resistance (Between V
OUT
and BAT)
Junction Temperature in Constant
Temperature Mode
BAT < V
TRKL
R
PROG
= 1k
R
PROG
= 5k
V
BUS
> V
UVLO
, Battery Charger Off, I
OUT
= 0μA
V
BUS
= 0V, I
OUT
= 0μA (Ideal Diode Mode)
●
Peak Switch Current Limit
3555f
3
LTC3555
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
I
PD1
I
2
C Port
DV
CC
I
DVCC
V
DVCC_UVLO
ADDRESS
V
IH
, SDA, SCL
V
IL
, SDA, SCL
I
PD2
SDA, SCL
V
OL
f
SCL
t
BUF
t
HD_STA
t
SU_STA
t
SU_STD
t
HD_DAT(OUT)
t
HD_DAT(IN)
t
SU_DAT
t
LOW
Input Supply Voltage
DV
CC
Current
DV
CC
UVLO
I
2
C Address
Input High Threshold
Input Low Threshold
Pull-Down Current
Digital Output Low (SDA)
Clock Operating Frequency
Bus Free Time Between Stop and Start
Condition
Hold Time After (Repeated) Start
Condition
Repeated Start Condition Setup Time
Stop Condition Time
Data Hold Time
Input Data Hold Time
Data Setup Time
Clock Low Period
I
PULLUP
= 3mA
400
1.3
0.6
0.6
0.6
225
0
100
1.3
900
70
30
2
0.4
SCL/SDA = 0kHz
1.6
0.5
1.0
0001 001[0]
%DV
CC
%DV
CC
μA
V
kHz
μs
μs
μs
μs
ns
ns
ns
μs
3555f
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, BAT = 3.8V, DV
CC
= 3.3V, R
PROG
= 1k, R
CLPROG
= 3k,
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
Rising Threshold
Hysteresis
Falling Threshold
Hysteresis
V
NTC
= V
BUS
= 5V
MIN
75.0
33.4
0.7
–50
2
15
0.18
1.6
0mA < I
LDO3V3
< 25mA
3.1
3.3
4
23
0.4
1.2
2
3.5
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
μA
V
BUS
= 0V, I
OUT
= 10mA
I
OUT
= 10mA
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
I
LIM0
, I
LIM1
, EN1, EN2, EN3
Pull-Down Currents
Always On 3.3V LDO Supply
Logic (I
LIM0
, I
LIM1
, EN1, EN2, EN3)
5.5
V
μA
V
4
LTC3555
ELECTRICAL CHARACTERISTICS
SYMBOL
t
HIGH
t
f
t
r
t
SP
V
IN1,2,3
V
OUTUVLO
PARAMETER
Clock High Period
Clock Data Fall Time
Clock Data Rise Time
Spike Suppression Time
Input Supply Voltage
V
OUT
UVLO—V
OUT
Falling
V
OUT
UVLO—V
OUT
Rising
Oscillator Frequency
FBx Input Current
Maximum Duty Cycle
SWx 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
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 (GBNT)
Forced Burst Mode Operation (GBNT)
LDO Mode (GBNT)
(Note 7)
V
FB1,2,3
= 0.85V
V
IN1,2,3
Connected to V
OUT
Through Low
Impedance. Switching Regulators are Disabled in
UVLO
The
●
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, BAT = 3.8V, DV
CC
= 3.3V, R
PROG
= 1k, R
CLPROG
= 3k,
unless otherwise noted.
CONDITIONS
MIN
0.6
20
20
50
2.7
2.5
2.6
2.8
2.25
5.5
2.9
2.7
50
10
225
35
20
20
600
400
60
50
0.78
800
300
300
TYP
MAX
UNITS
μs
ns
ns
ns
V
V
V
MHz
nA
%
kΩ
μA
μA
μA
μA
μA
mA
mA
mA
mA
V
Ω
Ω
Ω
Ω
μA
μA
μA
μA
μA
mA
mA
mA
mA
V
V
mV
General Purpose Switching Regulators 1, 2 and 3
f
OSC
I
FB1,2,3
D
1,2,3
R
SW1,2,3_PD
I
VIN1
1.8
–50
100
General Purpose Switching Regulator 1
60
35
35
1
1100
I
LIM1
I
OUT1
V
FB1
R
P1
R
N1
R
LDO_CL1
R
LDO_OL1
I
VIN2
V
FB1
Servo Voltage
PMOS R
DS(ON)
NMOS R
DS(ON)
LDO Mode Closed-Loop R
OUT
LDO Mode Open-Loop R
OUT
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
0.80
0.6
0.7
0.25
0.82
(Note 8)
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 (GBNT)
Forced Burst Mode Operation (GBNT)
LDO Mode (GBNT)
Full Scale (1, 1, 1, 1) (Note 7)
Zero Scale (0, 0, 0, 0) (Note 7)
2.5
225
35
20
20
600
400
60
50
0.78
0.405
800
General Purpose Switching Regulator 2
60
35
35
1
1100
I
LIM2
I
OUT2
V
FBHIGH2
V
FBLOW2
V
LSB2
Maximum Servo Voltage
Minimum Servo Voltage
V
FB2
Servo Voltage Step Size
0.80
0.425
25
0.82
0.445
Burst Mode is a registered trademark of Linear Technology Corporation.
3555f
5
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