LT8570_15 Datasheet, PDF (1/34 Pages) Linear Technology – Boost/SEPIC/Inverting DC/DC Converter with 65V Switch, Soft-Start and Synchronization

LT8570/LT8570-1
Boost/SEPIC/Inverting
DC/DC Converter with 65V
Switch, Soft-Start and Synchronization
Features
n _{65V Power Switch}
n _{Current Limit Options of 0.5A (LT8570) or 0.25A}
(LT8570-1)
n _{Adjustable Switching Frequency}
n _{Single Feedback Resistor Sets VOUT}
n _{Synchronizable to External Clock}
n _{High Gain SHDN Pin Accepts Slowly Varying}
Input Signals
n _{Wide Input Voltage Range: 2.55V to 40V}
n _{Low VCESAT Switch}
n _{Integrated Soft-Start Function}
n _{Easily Configurable as a Boost, SEPIC, or Inverting}
Converter
n _{User Configurable Undervoltage Lockout (UVLO)}
n _{Pin Compatible with LT3580 and LT8580}
n _{Tiny Thermally Enhanced 8-Lead 3mm × 3mm DFN}
and 8-Lead MSOP Packages
Applications
n _{VFD Bias Supplies}
n _{TFT-LCD Bias Supplies}
n _{GPS Receivers}
n _{DSL Modems}
n _{Local Power Supply}
Description
The LT^®8570 and LT8570-1 are PWM DC/DC converters.
The LT8570 contains a 0.5A, 65V power switch, while
the LT8570-1 contains a 0.25A, 65V power switch. The
LT8570 and LT8570-1 can be configured as either a boost,
SEPIC or inverting converter.
The LT8570/LT8570-1 have an adjustable oscillator, set
by a resistor from the RT pin to ground. Additionally, the
LT8570/LT8570-1 can be synchronized to an external
clock. The switching frequency of the part may be free
running or synchronized, and can be set between 200kHz
and 1.5MHz.
The LT8570/LT8570-1 also feature innovative SHDN pin
circuitry that allows for slowly varying input signals and
an adjustable undervoltage lockout function.
Additional features such as frequency foldback and soft-
start are integrated. The LT8570/LT8570-1 are available
in tiny thermally enhanced 3mm × 3mm 8-lead DFN and
8-lead MSOP packages.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Protected by U.S. Patents, including 7579816.
Typical Application
1.5MHz, 5V to 12V Boost Converter
22µH
V_IN
5V
10k
V_OUT
12V
125mA
V_IN
SHDN
SW
130k
FBX
1µF
LT8570
SYNC
VC
2.2µF
RT GND SS
6.19k
47pF
56.2k
0.1µF
2.2nF
8570 TA01a
100
90
80
70
60
50
40
30
20
0
Efficiency and Power Loss
320
280
240
200
160
120
80
EFFICIENCY ₄₀
POWER LOSS
0
25
50
75
100 125
LOAD CURRENT (mA)
8570 TA01b
For more information www.linear.com/LT8570
85701f
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