LT3587 Datasheet, PDF (1/24 Pages) Linear Technology – High Voltage Monolithic Inverter and Dual Boost

FEATURES
n _{Ideal for CCD, LCD, LED Backlight and OLED}
Applications
n _{Easy Generation of 15V (50mA), –8V (100mA) and}
20V (20mA) from a Li-Ion Cell
n _{VVIN Range: 2.5V to 6V}
n _{Wide Output Ranges: Up to 32V for the Boosts and}
Up to –32V for the Inverter
n _{Output Disconnect for the Boost Channels}
n _{Boost3 Allows Voltage Programming and/or Current}
Programming for a ‘One Wire Current Source’
n _{Overload Fault Protection with Fault I/O Pin Indicator}
n _{Combined Soft-Start and Enable Pins}
n _{Small 20-Pin 3mm × 3mm QFN Package}
APPLICATIONS
n _{Digital Still and Video Cameras}
n _{Scanner and Display Systems}
n _{PDA, Cellular Phones and Handheld Computers}
n _{LED Backlight and OLED Display Drivers}
n _{CCD Imager Bias}
n _{General High Voltage Supply Bias}
LT3587
High Voltage Monolithic
Inverter and Dual Boost
DESCRIPTION
The LT^®3587 provides a one chip solution for applications
requiring two positive and one negative high voltage sup-
plies. The LT3587 input voltage range of 2.5V to 6V makes
it ideal for various battery-powered systems.
A single resistor programs each of the three output voltage
levels and the output current of Boost3. The intelligent soft-
start allows for sequential soft-start of the Boost1 output
followed by the negative output with a single capacitor.
Internal sequencing circuitry also disables the inverter until
the Boost1 output has reached 87% of its final value.
The LT3587 integrates all the power switches, soft-start,
and output-disconnect circuits into a small 3mm × 3mm
QFN package. This high level of integration combined
with small external components makes the LT3587 ideal
for space constrained applications.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Li-Ion Powered Supply for CCD Imager and Six White Backlight LEDs
V_VIN
2.5V TO 6V
1μF
2.2μF
8.06k
10μH
15μH
SW3
CAP3
I_FB3
GND
VIN
LT3587
SW1
CAP1
V_OUT1
FB1
10μF
1M
2.7pF
V_VIN
2.5V TO 6V
EN/SS1
EN/SS3
FLT
SW2
15μH
2.2μF
V_OUT3
V_FB3
FB2
1M
6.8pF
15μH
CCD POSITIVE
15V, 50mA
LED DRIVER
20mA, UP TO 6 LEDS
22μF
CCD NEGATIVE
–8V, 100mA
3587 TA01a
Efficiency Curve
90 _{CDD+ = 50mA}
85 ^{CDD– = 100mA}
LED = 20mA
80
800
CDD⁺
700
600
75
ALL CHANNELS
500
ENABLED
70
CDD^–
400
65
LED
300
POWER DISSIPATION
60
ALL CHANNELS
200
ENABLED
55
100
50
0
0.5
1
NORMALIZED CURRENT
0
1.5
3587 TA01b
3587fc
1