LTC3554-3_15 Datasheet, PDF (1/36 Pages) Linear Technology – Micropower USB Power Manager with Li-Ion Charger and Two Step-Down Regulators

LTC3554/LTC3554-1/
LTC3554-2/LTC3554-3
Features
Micropower USB Power
Manager with Li-Ion Charger
and Two Step-Down Regulators
Description
n _{10μA 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}
n _{Dual High Efficiency Step-Down Switching Regulators}
(200mA I_OUT) with Adjustable Output Voltages
n _{Pushbutton On/Off Control with System Reset}
n _{Reset Time: 5 sec (LTC3554/LTC3554-1),}
14 sec (LTC3554-2/LTC3554-3)
n _{Full Featured Li-Ion/Polymer Battery Charger}
n _{Programmable Charge Current with Thermal Limiting}
n _{Instant-On Operation with Discharged Battery}
n _{Battery Float Voltage: 4.2V (LTC3554/LTC3554-2/}
LTC3554-3), 4.1V (LTC3554-1)
n _{3mm × 3mm × 0.75mm 20-Lead QFN Package}
Applications
n _{USB-Based Handheld Products}
n _{Portable Li-Ion/Polymer Based Electronic Devices}
n _{Fitness Computers}
n _{Low Power Medical Devices}
The LTC^®3554 family* are micropower, highly integrated
power management and battery charger ICs for single-cell
Li-Ion/Polymer battery applications. They include 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 LTC3554 power managers automatically limit
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 LTC3554 also includes two synchronous step-down
switching regulators as well as a pushbutton controller.
With all supplies enabled in standby mode, the quiescent
current drawn from the battery is only 10μA. The LTC3554
family are available in a 3mm × 3mm × 0.75mm 20-lead
QFN package.
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo 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.
*See table on page 2 for available options.
Typical Application
4.35V TO 5.5V
USB INPUT
100k
10µF
100k T
1.87k
V_BUS
V_OUT
NTC LTC3554 CHRG
PROG
BAT
10µF
+ Li-Ion
BATTERY
ON/OFF
HPWR
SUSP
PWR_ON1
FSEL
STBY
PGOOD
PWR_ON2
PBSTAT
ON
BVIN
2.2µF
4.7µH
SW1
10pF
FB1
SW2
FB2
3554 TA01a
10µH
10pF
2.05M
649k
332k
649k
SYSTEM
LOAD
3.3V
200mA
10µF
1.2V
200mA
10µF
Battery Drain Current
vs Temperature
14
V_BAT = 3.8V
STBY = 3.8V
12 _{REGULATORS LOAD = 0mA}
BOTH REGULATORS
10 _ENABLED
8
ONE REGULATOR ENABLED
6
BOTH REGULATORS DISABLED
4
2
HARD RESET
0
–75 –50 –25 0 25 50 75
TEMPERATURE (°C)
100 125
3554 TA01b
3554123ff
1