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Power Management and Signal Conditioning
InfoCard 19
Linear Technology Corporation • 1630 McCarthy Blvd. • Milpitas, CA 95035-7417 • (408) 432-1900 • www.linear-tech.com • Literature Only: 1-800-4-LINEAR
ic19b ©1997 LT/TP 0300 4K
DC/DC Conversion for LCD Bias
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Contrast Control for LCD Displays
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Boosted Positive or Negative Voltage Regulator with Small
Size, Very Low Component Height and Long Battery Life
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Peak Current Controlled to Keep the Inductor from
Saturating and to Limit Output Ripple
Inverting Converters for LCD Bias
Characteristics LT1615 LT1615-1 LT1617 LT1617-1
Input Voltage Range 1.2V to 15V 1V to 15V 1.2V to 15V 1V to 15V
Output Voltage Range to 34V to 34V to –34V to –34V
Max Switch Current 350mA 100mA 350mA 100mA
Supply Current 30µA30µA30µA30µA
Switching Frequency to 1.4MHz* to 1.4MHz* to 1.4MHz* to 1.4MHz*
Peak Efficiency 84% 84% 84% 84%
Other Features 34V Switch Single Cell Tiny Size Single Cell
Tiny Size Operation
Package SOT-23 SOT-23 SOT-23 SOT-23
*Constant off-time, variable on-time operation.
V
IN
SW
FB
LT1615
V
IN
2.5V TO 4.2V
L1
10µHD1
SHDN
R2
130k
R1
2M C2
1µF
20V
12mA
C1: TAIYO YUDEN LMK316BJ475
C2: TAIYO YUDEN TMK316BJ105
D1: MOTOROLA MBR0530
L1: MURATA LQH3C100K24
1615/-1 TA01
GND
C1
4.7µF
Single Cell Li-Ion to 20V Converter for LCD Bias
Color LCD Backlight Supply (White LEDs)
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LTC1754/LTC1751 Are Perfect for 3V to 5V Conversion to
Drive White LED Backlights for Color LCD Displays
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LTC1754 is Smallest 50mA Solution
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LTC1751 Adds Power Good and Undervoltage Outputs,
Plus 100mA Output
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LTC1751 Includes Soft-Start to Improve PWM Dimming
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LTC1682 for Lowest Noise: Includes LDO Post Regulator
C+
VIN
LTC1754-5
LTC1754-5
C–
ON OFF
VOUT
GND
SHDN
1
2
46
5
3100Ω
VIN
2.7V
TO 5.5V 10µF
50mA, UP TO FOUR WHITE LEDs
10µF
1µF
100Ω
• • •
100Ω
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Low Output Ripple: Less Than 1mV
P-P
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High Charge Pump Frequency: 900kHz
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Small Charge Pump Capacitors: 0.1µF
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Fixed –4.1V, –2.5V, –2V or Adjustable Output
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Shutdown Mode Drops Supply Current to 0.2µA
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High Output Current: Up to 20mA
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Output Regulation: 2.5%
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MSOP and SO-8 Packages
GaAs FET Bias Generator Family
Characteristics LTC1261L LTC1429 LTC1550L/LTC1551L
Min Input Voltage 2.7V 3V 2.7V
Quiescent Current 650µA 600µA 3.65mA
Oscillator Frequency 650kHz to 2MHz 900kHz
Other Features Converts –3.5V, –4V, –4.5V <1mV Output
3V to –4V –5V Outputs Ripple
Packages SO-8 SO-8, SO-14 SSOP-16
MSOP-8, SO-8
GaAs FET Bias
LTC1550L/LTC1551L: Low Noise Charge Pump Negative Bias Generators