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

Electrical Specifications Subject to Change
LTC3554
FEATURES
Micropower USB Power
Manager With Li-Ion Charger
and Two Step-Down Regulators
DESCRIPTION
n _{10μA Standby Mode with 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 _{Dual High Efficiency Step-Down Switching Regulators}
(200mA I_OUT) with Adjustable Output Voltages
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 _{Compact Ultra-Thin 3mm × 3mm × 0.55mm 20-Pin}
UTQFN Package
APPLICATIONS
n _{USB-Based Handheld Products}
n _{Portable Li-Ion/Polymer Based Electronic Devices}
The LTC^®3554 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 LTC3554 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 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 is available in a 3mm
× 3mm × 0.55mm 20-pin UTQFN package.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. 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, and other patents
pending.
TYPICAL APPLICATION
4.35V TO 5.5V
USB INPUT
100k
100k T
1.74k
ON/OFF
V_BUS
V_OUT
NTC
CHRG
LTC3554
PROG
BAT
10μF
Li-Ion
BATTERY
SYSTEM
LOAD
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
3.3V
200mA
10μF
649k
1.2V
200mA
332k
10μF
649k
Battery Drain Current
vs Temperature
14
V_BAT = 3.8V
STBY = 3.8V
12 _{REGULATORS LOAD = 0}
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
3554p
1