LTC3553-2_15 Datasheet, PDF (1/36 Pages) Linear Technology – Micropower USB Power Manager with Li-Ion Charger, Always-On LDO and Buck Regulator

LTC3553-2
FEATURES
Micropower USB Power
Manager with Li-Ion Charger,
Always-On LDO and Buck Regulator
DESCRIPTION
n _{12μA Standby Mode Quiescent Current (All Outputs On)}
n _{Seamless Transition Between Input Power Sources:}
Li-Ion/Polymer Battery and USB
n _{240mΩ Internal Ideal Diode Provides Low Loss}
PowerPath™
n _{High Efficiency 200mA Buck Regulator}
n _{Always-On 150mA Low Dropout (LDO) Linear}
Regulator
n _{Pushbutton On/Off Control With System Reset}
n _{Full Featured Li-Ion/Polymer Battery Charger}
n _{Programmable Charge Current With Thermal Limiting}
n _{Instant-On Operation With Discharged Battery}
n _{3mm × 3mm × 0.75mm 20-Pin QFN Package}
APPLICATIONS
n _{USB-Based Handheld Products}
n _{Portable Li-Ion/Polymer Based Electronic Devices}
n _{Wearable Electronics}
n _{Low Power Medical Devices}
The LTC^®3553-2 is a micropower, highly integrated
power management and battery charger IC for single-cell
Li-Ion/Polymer battery applications. It includes a
PowerPath manager with automatic load prioritization,
a battery charger, an ideal diode and numerous internal
protection features. Designed specifically for USB applica-
tions, the LTC3553-2 power manager automatically limits
input current to a maximum of either 100mA or 500mA.
Battery charge current is automatically reduced such that
the sum of the load current and the charge current does
not exceed the selected input current limit. The LTC3553-2
also includes a synchronous buck regulator, an always-on
low dropout linear regulator (LDO), and a pushbutton
controller. With all supplies enabled in standby mode, the
quiescent current drawn from the battery is only 12μA.
The LTC3553-2 is available in a 3mm × 3mm × 0.75mm
20-pin QFN package.
L, LT, LTC, LTM, Linear Technology, the Linear logo, and Burst Mode are registered trademarks
and PowerPath, Hot Swap, 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, 6700364, 5481178, 6304066, 6570372, 6580258, 7511390 and other
patents pending.
TYPICAL APPLICATION
4.35V TO 5.5V
USB INPUT
100k
10μF
100k T
1.87k
DIGITAL
CONTROL
ON/OFF
V_BUS
V_OUT
NTC ^LTC3553-2 CHRG
10μF
PROG
BAT
+ Li-Ion
BATTERY
SYSTEM
LOAD
PGOOD
HPWR
SUSP
BUCK_ON
STBY
PBSTAT
ON
BVIN
V_INLDO
2.2μF
LDO
LDO_FB
2.05M
3.3V
150mA
4.7μF
649k
SW
BUCK_FB
35532 TA01a
10μH
10pF
1.2V
200mA
332k
10μF
649k
Battery Drain Current
vs Temperature
18
V_BAT = 3.8V
16 ^{STBY = 3.8V}
REGULATORS LOAD = 0mA
14
BUCK AND LDO ON
12
10 ONLY LDO ON
8
6
4
2
HARD RESET
0
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
35532 TA01b
35532f
1