LT3462_15 Datasheet, PDF (1/8 Pages) Linear Technology – Inverting 1.2MHz/2.7MHz DC/DC Converters with Integrated Schottky in ThinSOT

LT3462/LT3462A
Inverting 1.2MHz/2.7MHz
DC/DC Converters with
Integrated Schottky in ThinSOT
FEATURES
s _{Integrated Schottky Rectifier}
s _{Fixed Frequency 1.2MHz/2.7MHz Operation}
s _{Very Low Noise: 1mVP-P Output Ripple}
s _{Low VCESAT Switch: 270mV at 250mA}
s _{–5V at 100mA from 5V Input}
s _{–12V at 30mA from 3.3V Input}
s _{Low Input Bias Current GND Based FB Input}
s _{Low Impedance (40Ω) 1.265V Reference Output}
s _{High Output Voltage: Up to – 38V}
s _{Wide Input Range: 2.5V to 16V}
s _{Uses Tiny Surface Mount Components}
s _{Low Shutdown Current: <10µA}
s _{Low Profile (1mm) SOT-23 (ThinSOT}^TM_{) Package}
U
APPLICATIO S
s _{CCD Bias}
s _{LCD Bias}
s _{GaAs FET Bias}
s _{General Purpose Negative Voltage Supply}
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation
DESCRIPTIO
The LT^®3462/LT3462A are general purpose fixed fre-
quency current mode inverting DC/DC converters. Both
devices feature an integrated Schottky and a low V_CESAT
switch allowing a small converter footprint and lower parts
cost. The LT3462 switches at 1.2MHz while the LT3462A
switches at 2.7MHz. These high speeds enable the use of
tiny, low cost and low height capacitors and inductors.
The LT3462/LT3462A operate in a dual inductor inverting
topology that filters both the input and output currents.
Very low output voltage ripple approaching 1mV_P-P can be
achieved when ceramic capacitors are used. Fixed fre-
quency switching ensures a clean output free from low
frequency noise typically present with charge pump solu-
tions. The 40V switch allows a V_IN to V_OUT differential of
up to 38V for dual inductor topologies.
Both devices provide a low impedance 1.265V reference
output to supply the feedback resistor network. A ground
referenced, high impedance FB input allows high feedback
resistor values without compromising output accuracy.
The LT3462/LT3462A are available in a 6-lead SOT-23
package.
TYPICAL APPLICATIO
5V to –5V, 100mA Inverting DC/DC Converter
V_IN
22µH
1µF
22µH
5V
V_OUT
–5V
SW D
267k
100mA
22pF
1µF
V_IN
FB
LT3462A
68.1k
10µF
SDREF
GND
3462 TA01
75
T_A = 25°C
70
65
Efficiency
V_IN = 5V
V_IN = 3.3V
60
55
0
20
40
60
80 100
LOAD CURRENT (mA)
3462 TA01b
3462af
1