LTC3101_15 Datasheet, PDF (1/34 Pages) Linear Technology – Wide VIN, Multi-Output DC/DC Converter and PowerPath Controller

FEATURES
n _{Low Loss PowerPath™ Control: Seamless,}
Automatic Transition from Battery to USB or
Wall Adapter Power
n _{Wide VIN Range: 1.8V to 5.5V}
n _{Buck-Boost VOUT: 1.5V to 5.25V}
n _{Buck-Boost Generates 3.3V at 300mA for}
V_IN ≥ 1.8V, 3.3V at 800mA for V_IN ≥ 3V
n _{Dual 350mA Buck Regulators, VOUT: 0.6V to VIN}
n _{38μA Quiescent Current in Burst Mode}^® _Operation
n _{1.8V, 50mA Always-On LDO}
n _{Protected 100mA Hot Swap™ Output}
n _{Pushbutton On/Off Control}
n _{Current Limited 200mA MAX Output}
n _{Programmable Power-Up Sequencing}
n _{24-lead 4mm × 4mm × 0.75mm QFN Package}
APPLICATIONS
n _{Ultra-Portable Digital Video Cameras}
n _{Personal Handheld GPS Navigators}
n _{Portable Medical Instruments}
LTC3101
Wide V_IN, Multi-Output
DC/DC Converter and
PowerPath Controller
DESCRIPTION
The LTC^®3101 is a complete power management solution
for low power portable devices. It provides three high
efficiency switching DC/DC converters which seamlessly
transition from battery to USB/wall adapter power when
available. A synchronous buck-boost regulator provides
complete flexibility, allowing operation from a single
Li-Ion/Polymer battery, 2 to 3 AA cells, a USB port or any
other power source operating from 1.8V to 5.5V.
Two always-alive outputs, a 50mA LDO and a 200mA MAX
output that tracks the higher voltage input supply, provide
power for critical functions or additional external regula-
tors. Flash memory cards can be directly powered from
the protected 100mA Hot Swap output. Pushbutton control
logic and a programmable-duration microprocessor reset
generator simplify interfacing to a microprocessor while
internal sequencing and independent enable pins provide
flexible power-up options. The LTC3101 is available in a low
profile (0.75mm) 24-lead 4mm × 4mm QFN package.
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
and Hot Swap and PowerPath are trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
TYPICAL APPLICATION
2 AA ⁺
10μF
CELLS
4.7μH
10μF _1M
V_OUT3 = 3.3V
300mA FOR V_IN ≥ 1.8V
800mA FOR V_IN ≥ 3V
USB/WALL
ADAPTER
4.3V TO 5.5V
10μF
0.1μF
DIS ENA
ON/OFF
μP
BAT1 BAT2 SW3A
USB1
USB2
C_RS
SW3B OUT3
FB3
HSO
MAX
LDO
ENA1
ENA2
SW2
ENA3
LTC3101
FB2
PWRKEY
PBSTAT
PWM
SW1
PWRON
RESET
FB1
GND
221k
Hot Swap OUTPUT: 3.3V AT 100mA
TRACKING OUTPUT: 200mA
1.8V AT 50mA
4.7μH
221k
4.7μF
10μF
V_OUT2
1.8V
350mA
110k
4.7μH
221k
10μF
V_OUT1
1.5V
350mA
147k
3101 TA01a
Efficiency vs V_BAT
96
BUCK-BOOST
I_OUT = 150mA
94
92
BUCK2
90
I_OUT = 150mA
BUCK1
88
I_OUT = 150mA
86
84
1.5
2.5
3.5
4.5
5.5
V_BAT (V)
3101 TA01b
3101fb
1