LTC3100 Datasheet, PDF (1/24 Pages) Linear Technology – 1.5MHz Synchronous Dual Channel DC/DC Converter and 100mA LDO

FEATURES
n _{Extremely Compact Triple-Rail Solution}
n _{Burst Mode}^® _{Operation, IQ = 15μA}
n _{1.5MHz Fixed Frequency Operation}
n _{Power Good Indicators}
n _{700mA Synchronous Step-Up DC/DC}
0.65V to 5V V_IN Range
1.5V to 5.25V V_OUT Range
94% Peak Efficiency
V_IN > V_OUT Operation
Output Disconnect
n _{250mA Synchronous Step-Down DC/DC}
1.8V to 5.5V V_IN Range
0.6V to 5.5V V_OUT Range
n _{LDO (VIN Internally Tied to VBST)}
0.6V to 5.25V V_OUT Range
200mV Dropout Voltage at 100mA
n _{Available in a 16-Lead 3mm × 3mm QFN Package}
APPLICATIONS
n _{Bar Code Readers}
n _{Medical Instruments}
n _{Low Power Portable Electronic Devices}
LTC3100
1.5MHz Synchronous Dual
Channel DC/DC Converter
and 100mA LDO
DESCRIPTION
The LTC^®3100 combines a high efficiency 700mA syn-
chronous step-up converter, a 250mA synchronous
step-down converter and a 100mA LDO regulator. The
LTC3100 features a wide input voltage range of 0.65V to
5V. The step-down converter can be powered by the output
of the step-up converter or from a separate power source
between 1.8V and 5.5V. The LDO can also be used as a
sequencing switch on the output of the boost.
A switching frequency of 1.5MHz minimizes solution foot-
print by allowing the use of tiny, low profile inductors and
ceramic capacitors. The switching regulators use current
mode control and are internally compensated, reducing
external parts count. Each converter automatically transi-
tions to Burst Mode operation to maintain high efficiency
over the full load range. Burst Mode operation can be
disabled for low noise applications. The integrated LDO
provides a third low noise, low dropout supply.
Anti-ringing circuitry reduces EMI by damping the boost
inductor in discontinuous mode. Additional features
include shutdown current of under 1μA and overtem-
perature shutdown. The LTC3100 is housed in a 16-lead
3mm × 3mm 0.75mm QFN package.
, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology
Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Two-Cell, Triple Output Converter
3.3μH
V_BATT
1.6V TO 3.2V
2.2μF
SWBST V_INBK V_BST
V_INBST
FBBST
LTC3100
PGBST
V_LDO
FF EN_BURST
BOOST ^{OFF ON}
LDO ^{OFF ON}
BUCK ^{OFF ON}
MODE
RUNBST
FBLDO
SWBK
4.7μH
RUNLDO
FBBK
RUNBK GND
PGBK
3100 TA01a
1.87M
1.07M
102k
25.5k
2M
1M
10μF
s2
2.2μF
10μF
3.3V AT 100mA
V_BOOST
1M
BOOST_GOOD
3V AT 50mA
V_LDO
1.8V AT 200mA
V_BUCK
1M
BUCK_GOOD
Efficiency and Power Loss
vs Load Current, V_IN = 2.4V
100
90
80
70
60
50
40
30
20
10
0
0.01
1000
100
10
1
BOOST
BUCK
0.1
0.1
1
PL, BOOST
PL, BUCK
0.01
10 100 1000
LOAD CURRENT (mA)
3100 TA01b
3100fa
1