LT3495_15 Datasheet, PDF (1/16 Pages) Linear Technology – 650mA/350mA Micropower Low Noise Boost Converter with Output Disconnect

FEATURES
n _{Low Quiescent Current}
60µA in Active Mode
0.1µA in Shutdown Mode
n _{Low Noise Control Scheme (Switching Frequency}
Always Stays Above Audible Range for LT3495/-1)
n _{Integrated Power NPN:}
650mA Current Limit (LT3495/B)
350mA Current Limit (LT3495-1/B-1)
n _{Integrated Output Disconnect}
n _{Integrated Output Dimming}
n _{Wide input range: 2.5V to 16V}
n _{Wide output range: Up to 40V}
n _{Integrated feedback resistor}
n _{Tiny 10-Lead 3mm × 2mm DFN Package}
APPLICATIONS
n _{OLED Power}
n _{Low Noise Power}
n _{MP3 Player}
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. *Patent pending.
LT3495/LT3495B/
LT3495-1/LT3495B-1
650mA/350mA Micropower
Low Noise Boost Converter
with Output Disconnect
DESCRIPTION
The LT^®3495/LT3495B/LT3495-1/LT3495B-1 are low noise
boost converters with integrated power switch, feedback
resistor and output disconnect circuitry. The parts control
power delivery by varying both the peak inductor current
and switch off-time. This novel* control scheme results
in low output voltage ripple as well as high efficiency
over a wide load range. For the LT3495/LT3495-1, the
off-time of the switch is not allowed to exceed a fixed
level, guaranteeing the switching frequency stays above
the audio band for the entire load range. The parts feature
a high performance NPN power switch with a 650mA
and 350mA current limit for the LT3495/LT3495B and
LT3495-1/LT3495B-1 respectively. The quiescent current
is a low 60µA, which is further reduced to less than 0.1µA
in shutdown. The internal disconnect circuitry allows the
output voltage to be isolated from the input during shut-
down. An auxiliary reference input (CTRL pin) overrides
the internal 1.235V feedback reference with any lower
value allowing full control of the output voltage during
operation. The LT3495 series are available in a tiny 10-lead
3mm × 2mm DFN package.
TYPICAL APPLICATION
OLED Power Supply from One Li-Ion Cell
ONE
Li-Ion
CELL
10µH
4.7µF
SW CAP
V_CC V_OUT
LT3495
SHDN FB
CTRL GND
2.2µF
909k
V_OUT
16V
70mA
1µF
3495 TA01a
Output Voltage Ripple
vs Load Current
50
1.0µF 0603
40 ^{CAPACITOR AT V}OUT
30
20
10
0
0.1
2.2µF 1206
CAPACITOR AT V_OUT
1
10
LOAD CURRENT (mA)
100
3495 TA01b
Efficiency vs Load Current
90
V_IN = 3.6V
80
400
LOAD FROM CAP
LOAD FROM V_OUT 320
70
240
60
160
50
80
40
0.1
1
10
LOAD CURRENT (mA)
0
100
3495 TA01c
3495b1b1fa
1