LTC3212 Datasheet, PDF (1/12 Pages) Linear Technology – RGB LED Driver and Charge Pump

Features
■ _{Power and Current Control for Driving RGB LEDs}
■ _{Individually Programmable Current Sources}
■ _{1x or 2x Mode, Low Noise, Constant Frequency}
Charge Pump
■ _{Single Wire Enable Control for All LEDs}
■ _{White Mode Adjusts R, G, B Currents for White Light}
■ _{25mA Maximum LED Current}
■ _{VIN Range: 2.7V to 5.5V}
■ _{Automatic Soft-Start, Mode Switching and Output}
Disconnect in Shutdown Mode
■ _{Available in 12-Lead (3mm × 2mm) DFN Package}
Applications
■ _{Cellular Phones}
■ _{Media Players}
■ _{RGB Back Lights}
, 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.
LTC3212
RGB LED Driver and
Charge Pump
Description
The LTC^®3212 is a low noise charge pump RGB LED
driver capable of driving three LEDs up to 25mA each
from a 2.7V to 5.5V input. Low external part count (one
flying capacitor, two bypass capacitors and one to three
programming resistors) makes the LTC3212 ideally suited
for small, battery-powered applications.
Built-in soft-start circuitry prevents excessive inrush cur-
rent during start-up and mode switching. High switching
frequency enables the use of small external capacitors.
The charge pump shuts down to a high impedance mode
to prevent LED leakage while the LTC3212 is off.
Each LED may be individually turned on or off via a single
pin interface. The current through the LEDs may be indi-
vidually programmed with resistors or may share a single
programming resistor. White mode adjusts the red, green
and blue LED current ratios for a white light when all three
LEDs are programmed to be on.
LED currents are regulated using internal low dropout
current sources. Automatic mode switching optimizes
efficiency by monitoring the LED current drivers and
switches mode only when dropout is detected. The part
is available in a 3mm × 2mm 12-lead DFN package.
Typical Application
RGB Power Supply and Current Control
1µF
V_IN
2.7V TO 5.5V
1µF
11.8k
CM
CP
V_IN
CPO
LTC3212
R
LEDR
LEDEN
I_SETB
I_SETR
I_SETG
LEDG
LEDB
G
B
1µF
INDIVIDUAL WHITE
SETTINGS MODE
LEDR
LEDG
LEDB
15mA
15mA
15mA
13.5mA
15mA
11.2mA
3212 TA01a
3212fb