LTC3458_15 Datasheet, PDF (1/16 Pages) Linear Technology – 1.4A, 1.5MHz Synchronous Step-Up DC/DC Converter with Output Disconnect

FEATURES
■ _{High Efficiency: Up to 93%}
■ _{Inrush Current Limiting and Output Disconnect}
■ _{Programmable Output Voltages up to 7.5V}
■ _{1.5V to 6V Input Range}
■ _{Programmable/Synchronizable Fixed Frequency}
Operation up to 1.5MHz
■ _{Programmable Automatic Burst Mode}^® _Operation
■ _{Current Mode Control with Programmable Soft-Start}
Period and Peak Current Limit
■ _{700mA at 7V from 5V Input}
■ _{0.3Ω N-Channel and 0.4Ω P-Channel 1.4A Switches}
at 5V_OUT
■ _{Ultralow Quiescent Currents: 15μA Sleep, <1μA in}
Shutdown
■ _{3mm × 4mm Thermally Enhanced DFN Package}
U
APPLICATIO S
■ _{Point-of-Load Regulators}
■ _{USB VBUS Power}
■ _{LCD Bias}
■ _{OLED Displays}
LTC3458
1.4A, 1.5MHz Synchronous
Step-Up DC/DC Converter
with Output Disconnect
DESCRIPTIO
The LTC^®3458 is a high efficiency, current mode, fixed
frequency, step up DC/DC converter with true output
disconnect and inrush current limiting. The LTC3458 is
rated for a 7.5V output and includes a 0.3Ω N-channel
MOSFET switch and a 0.4Ω P-channel MOSFET synchro-
nous rectifier. The LTC3458 is well suited for battery
powered applications and includes programmable output
voltage, switching frequency and loop compensation. The
oscillator frequency can be set up to 1.5MHz or synchro-
nized to an external clock.
Quiescent current is only 15μA during Burst Mode opera-
tion maximizing battery life in portable applications. The
Burst Mode current threshold, peak current limit, and soft-
start are externally programmable. Other features include
<1μA shutdown current, antiringing control, and thermal
limit. The LTC3458 is available in a low profile (0.75mm),
3mm × 4mm 12-pin DFN package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Burst Mode is a registered trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
USB to 7V at 1MHz
COEV
10μH
DQ7545
USB
4.35V to 5.25V
2.2μF
V_IN
SW
LTC3458
GND/PGND
V_OUT
ON OFF
SHDN
FB
SYNC
R_T
I_LIM
200k 124k
COMP
0.01μF
SS
BURST
0.01μF
133k
10pF
1.5M
V_OUT
7V
500mA
33k
10pF
560pF
316k
22μF
X5R
3458 TA01a
USB to 7V_OUT
100
1000
95
5.25V_IN
90
4.35V_IN
85
10
POWER LOSS
80
75
70
0.1
1
10
100
LOAD CURRENT (mA)
0.1
1000
3458 TA01b
3458fa
1