LTC3577-3/LTC3577-4
Highly Integrated
Portable Product PMIC
FEATURES
DESCRIPTION
The LTC®3577-3/LTC3577-4 are highly integrated power
managementICsforsinglecellLi-Ion/Polymerbatteryap-
plications.ItincludesaPowerPathmanagerwithautomatic
load prioritization, a battery charger, an ideal diode, input
overvoltage protection and numerous other internal pro-
tection features. The LTC3577-3/LTC3577-4 are designed
toaccuratelychargefromcurrentlimitedsuppliessuchas
USB by automatically reducing charge current such that
the sum of the load current and the charge current does
notexceedtheprogrammedinputcurrentlimit(100mAor
500mAmodes).TheLTC3577-3/LTC3577-4reducethebat-
teryvoltageatelevatedtemperaturestoimprovesafetyand
reliability. The three step-down switching regulators and
two LDOs provide a wide range of available supplies. The
LTC3577-3/LTC3577-4 also include a pushbutton input to
controlpowersequencingandsystemreset. Theonboard
LED backlight boost circuitry can drive up to 10 series
LEDs and includes versatile digital dimming via the I2C
input.TheLTC3577-3/LTC3577-4aredesignedtosupport
the SiRF Atlas IV processor and has pushbutton timing
and sequencing different from other LTC3577 versions.
The LTC3577-3/LTC3577-4 are available in a low profile
4mm × 7mm × 0.75mm 44-pin QFN package.
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Full Featured Li-Ion/Polymer Charger/PowerPath™
Controller with Instant-On Operation
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Triple Adjustable High Efficiency Step-Down
Switching Regulators (800mA, 500mA, 500mA I
)
OUT
2
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I C Adjustable SW Slew Rates for EMI Reduction
High Temperature Battery Voltage Reduction
Improves Safety and Reliability
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Overvoltage Protection Controller for USB (V )/Wall
BUS
Inputs Provide Protection to 30V
Integrated 40V Series LED Back Light Driver with 60dB
2
Brightness Control and Gradation via I C
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1.5A Maximum Charge Current with Thermal Limiting
Battery Float Voltage: 4.2V (LTC3577-3)
4.1V (LTC3577-4)
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Pushbutton ON/OFF Control with System Reset
Dual 150mA Current Limited LDOs
Start-Up Timing Compatible with SiRF Atlas IV
Processor
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Small 4mm × 7mm 44-Pin QFN Package
APPLICATIONS
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PNDs, DMB/DVB-H, Digital/Satellite Radio,
Media Players
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
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, 6700364,
7511390, 5481178, 6580258. Other patents pending.
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Portable Industrial/Medical Products
Other USB-Based Handheld Products
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TYPICAL APPLICATION
5V
LED Driver Efficiency (10 LEDs)
ADAPTER
OPTIONAL
90
100mA/500mA
1000mA
USB
80
70
60
V
OUT
0V
OVERVOLTAGE
PROTECTION
CC/CV
MAX PWM
CONSTANT
CURRENT
CHARGER
+
SINGLE CELL
Li-Ion
50
40
30
20
10
0
CHARGE
NTC
LTC3577-3/LTC3577-4
2
0.8V to 3.6V/150mA
0.8V to 3.6V/150mA
DUAL LDO
REGULATORS
2
I C PORT
LED BACKLIGHT WITH DIGITALLY
CONTROLLED DIMMING
4 TO 10 LED
BOOST
TRIPLE HIGH
0.8V to 3.6V/800mA
0.8V to 3.6V/500mA
0.8V to 3.6V/500mA
EFFICIENCY
PUSHBUTTON
CONTROL
1000
100
10
1
0.1
0.01
PB
STEP-DOWN
LED CURRENT (mA)
SWITCHING
REGULATORS
357734 TA01b
357734 TA01a
357734fb
1