LTC3220/LTC3220-1
360mA Universal
18-Channel LED Driver
FEATURES
DESCRIPTION
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Eighteen 20mA Universal Current Sources with
TheLTC3220/LTC3220-1arehighlyintegratedmulti-display
LEDdrivers.Thesepartscontainahighefficiency,lownoise
charge pump to provide power to up to eighteen universal
LED current sources. The LTC3220/LTC3220-1 require
only five small ceramic capacitors to form a complete
LED power supply and current controller.
64-Step Linear Brightness Control
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Independent On/Off, Brightness Level, Blinking and
Gradation Control for Each Current Source Using
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2-Wire I C Interface
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Low Noise Multi-Mode Charge Pump (1x, 1.5x, 2x)
Provides Up to 91% Efficiency
The LED currents are set by an internal precision cur-
rent reference. Independent dimming, on/off, blinking
and gradation control for all universal current sources
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Slew Limited Switching Reduces Conducted and
Radiated Noise (EMI)
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Up to 360mA Total Output Current
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is achieved via the I C serial interface. 6-bit linear DACs
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Internal Current Reference
are available to adjust brightness levels independently for
each universal LED current source.
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Single Reset Pin for Asynchronous Shutdown and
Reset of All Data Registers
2
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TheLTC3220/LTC3220-1chargepumpoptimizesefficiency
based on the voltage across the LED current sources. The
part powers up in 1x mode and will automatically switch
to boost mode whenever any enabled LED current source
begins to enter dropout. The first dropout switches the
parts into 1.5x mode and a subsequent dropout switches
the LTC3220/LTC3220-1 into 2x mode. The parts reset to
Two I C Addresses Are Available (LTC3220: 0011100,
LTC3220-1: 0011101)
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Automatic or Forced Mode Switching
Internal Soft-Start Limits Inrush Current
Short-Circuit/Thermal Protection
4mm × 4mm Ultrathin (0.55mm) 28-Lead QFN
Package
2
1x mode whenever a data bit is updated via the I C port.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 6411531.
APPLICATIONS
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Video Phones with QVGA+ Displays
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Keypad Lighting
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General/Miscellaneous Lighting
TYPICAL APPLICATION
6-LED Main, 4 RGB LEDs
C2
C3
2.2μF
2.2μF
RGB1
RGB2
RGB3
RGB4
MAIN
C1P C1M C2P C2M
V CPO
IN
V
IN
C4
C1
LTC3220
LTC3220-1
4.7μF
2.2μF
18
DV
CC
ULED1-18
DV
CC
0.1μF
3220 TA01
2
SCL/SDA
I C
RESET
RST
GND
32201fc
1