Step-Down DC/DC. LTC3555 Datasheet

LTC3555 DC/DC. Datasheet pdf. Equivalent

Part LTC3555
Description High Efficiency USB Power Manager + Triple Step-Down DC/DC
Feature www.DataSheet4U.com FEATURES POWER MANAGER ■ High Efficiency Switching PowerPathTM Controller with B.
Manufacture Linear Technology
Datasheet
Download LTC3555 Datasheet




LTC3555
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FEATURES
POWER MANAGER
High Efficiency Switching PowerPathTM Controller
with Bat-TrackTM 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 IOUT)
All Regulators Operate at 2.25MHz
Dynamic Voltage Scaling on Two Outputs
I2C or Independent Enable, VOUT Controls
Low No-Load Quiescent Current: 20μA
28-Pin (4mm × 5mm × 0.75mm) QFN Surface
Mount Package
APPLICATIONS
HDD-Based MP3 Players, PDAs, GPS, PMPs
Other USB-Based Handheld Products
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 I2C 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
TYPICAL APPLICATION
High Efficiency PowerPath Manager and Triple Step-Down Regulator
USB/WALL
4.35V TO 5.5V
CHARGE
ENABLE 5
CONTROLS
USB COMPLIANT
STEP-DOWN
REGULATOR
CC/CV
BATTERY
CHARGER
0V
LTC3555
ALWAYS ON LDO
TRIPLE
HIGH EFFICIENCY
STEP-DOWN
SWITCHING
REGULATORS
1
2
3
I2C PORT
TO OTHER
LOADS
OPTIONAL
+
T Li-Ion
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
I2C
3555 TA01
Switching Regulator Efficiency to
System Load (POUT/PBUS)
100
90
80
70 BAT = 4.2V
60
BAT = 3.3V
50
40
30
20 VBUS = 5V
10 IBAT = 0mA
10x MODE
0
0.01
0.1
IOUT (A)
1
3555 TA01b
3555f
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LTC3555
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LTC3555
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2, 3)
VBUS (Transient) t < 1ms,
Duty Cycle < 1% .......................................... –0.3V to 7V
VIN1, VIN2, VIN3, VBUS (Static), DVCC,
FB1, FB2, FB3, NTC, BAT, EN1, EN2, EN3,
ILIM0, ILIM1, SCL, SDA, RST3, CHRG............ –0.3V to 6V
ICLPROG ....................................................................3mA
IRST3, ICHRG............................................................50mA
IPROG........................................................................2mA
ILDO3V3 ...................................................................30mA
ISW1, ISW2 ............................................................600mA
ISW, ISW3, IBAT, IVOUT ...................................................2A
Junction Temperature ........................................... 125°C
Operating Temperature Range ................. –40°C to 85°C
Storage Temperature Range................... –65°C to 125°C
PACKAGE/ORDER INFORMATION
TOP VIEW
28 27 26 25 24 23
LDO3V3 1
22 GATE
CLPROG 2
21 CHRG
NTC 3
20 PROG
FB2 4
VIN2 5
SW2 6
19 FB1
29
18 VIN1
17 SW1
EN2 7
16 EN1
DVCC 8
15 RST3
9 10 11 12 13 14
UFD PACKAGE
28-LEAD (4mm × 5mm) PLASTIC QFN
TJMAX = 125°C, θJA = 37°C/W
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB
ORDER PART NUMBER UFD PART MARKING
LTC3555EUFD
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 The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VBUS = 5V, BAT = 3.8V, DVCC = 3.3V, RPROG = 1k, RCLPROG = 3k,
unless otherwise noted.
SYMBOL
PARAMETER
PowerPath Switching Regulator
CONDITIONS
MIN TYP
MAX UNITS
VBUS
IBUSLIM
Input Supply Voltage
Total Input Current
IVBUSQ
VBUS Quiescent Current
hCLPROG
(Note 4)
Ratio of Measured VBUS Current to
CLPROG Program Current
IOUT(POWERPATH) VOUT Current Available Before
Loading BAT
1x Mode, VOUT = BAT
5x Mode, VOUT = BAT
10x Mode, VOUT = BAT
Suspend Mode, VOUT = BAT
1x Mode, IOUT = 0mA
5x Mode, IOUT = 0mA
10x Mode, IOUT = 0mA
Suspend Mode, IOUT = 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
4.35
87
436
800
0.31
95
460
860
0.38
7
15
15
0.044
224
1133
2140
11.3
135
672
1251
0.32
5.5 V
100 mA
500 mA
1000 mA
0.50 mA
mA
mA
mA
mA
mA/mA
mA/mA
mA/mA
mA/mA
mA
mA
mA
mA
3555f
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