LTC3535_15 Datasheet, PDF (1/16 Pages) Linear Technology – Dual Channel 550mA 1MHz Synchronous Step-Up DC/DC Converter

LTC3535
FEATURES
Dual Channel 550mA 1MHz
Synchronous Step-Up
DC/DC Converter
DESCRIPTION
n _{Two Independent Step-Up Converters}
n _{Each Channel Delivers 3.3V at 100mA from a Single}
Alkaline/NiMH Cell or 3.3V at 200mA from Two Cells
n _{VIN Start-Up Voltage: 680mV}
n _{1.5V to 5.25V VOUT Range}
n _{Up to 94% Efficiency}
n _{Output Disconnect}
n _{1MHz Fixed Frequency Operation}
n _{VIN > VOUT Operation}
n _{Integrated Soft-Start}
n _{Current Mode Control with Internal Compensation}
n _{Burst Mode}^® _{Operation with 9µA IQ Each Channel}
n _{Internal Synchronous Rectifier}
n _{Logic Controlled Shutdown (IQ < 1µA)}
n _{Anti-Ring Control}
n _{Low Profile (3mm × 3mm × 0.75mm)}
12-Lead DFN Package
APPLICATIONS
n _{Medical Instruments}
n _{Noise Canceling Headphones}
n _{Energy Harvesting}
n _{Bluetooth Headsets}
The LTC^®3535 is a dual channel, synchronous, fixed fre-
quency step-up DC/DC converter with output disconnect.
Extended battery life in single AA/AAA powered products
is realized with a 680mV start-up voltage and operation
down to 500mV once started.
A switching frequency of 1MHz minimizes solution foot-
print by allowing the use of tiny, low profile inductors
and ceramic capacitors. The current mode PWM design
is internally compensated, reducing external parts count.
The LTC3535 features Burst Mode operation at light load
conditions allowing it to maintain high efficiency over a
wide range of load. Anti-ring circuitry reduces EMI by
damping the inductor in discontinuous mode. Additional
features include a low shutdown current of under 1µA and
thermal shutdown.
The LTC3535 is housed in a 3mm × 3mm × 0.75mm
DFN package.
L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
TYPICAL APPLICATION
4.7µH
V_IN
0.8V
TO 1.5V
OFF ON
2.2µF
OFF ON
SW1
V_IN1
V_OUT1
SHDN1 V_OUT2
LTC3535
V_IN2
FB1
SHDN2
FB2
GND SW2 GND
4.7µH
10µF
10µF
V_OUT2
3.3V
50mA
1.78M
V_OUT1
1.8V
100mA
511k
1M
1M
3535 TA01
Efficiency vs Load Current
100
90
V_OUT = 1.8V
80
70
V_OUT = 3.3V
60
50
40
30
20
10
0 ^{VIN = 1.2V}
0.01 0.1
1
10
100
LOAD CURRENT (mA)
1000
3535 TA01b
3535fa
1