AAT3340_08 Datasheet, PDF (1/14 Pages) Advanced Analogic Technologies – High Efficiency 1x/1.5x Charge Pump

ChargePump^TM
General Description
The AAT3340 is a low-noise, constant-frequency charge
pump DC/DC converter that uses a dual-mode load switch
(1x) and fractional (1.5x) conversion to maximize effi-
ciency for white LED applications. The AAT3340 is capable
of driving 4 white LEDs at a total of 80mA from a single
2.7V to 5.5V input. The current sinks may be operated
individually or in parallel while driving higher-current
LEDs. A low external parts count (two 1μF flying capacitors
and two small 1μF capacitors at V_IN and V_OUT) makes the
AAT3340 ideal for small battery-powered applications.
Analogic Tech’s Simple Serial Control (S²Cwire) digital
interface is used to enable, disable and set current to
one of 32 levels for the LEDs.
The AAT3340 is equipped with built-in short-circuit and
over-temperature protection. The soft-start circuitry pre-
vents excessive inrush current at start-up and mode
transitions. The AAT3340 family is available in Pb-free,
space-saving TSOPJW and TDFN33 packages, and oper-
ates over the -40°C to +85°C ambient temperature
range.
PRODUCT DATASHEET
AAT3340
High Efficiency 1x/1.5x Charge Pump
Features
• Dual-Mode (1x/1.5x) Charge Pump
• Drives up to 4-Channel Backlight LEDs
• 32-Level Programmable Backlight Current (linear,
inverting)
• Single-wire S²_{Cwire Control}
• Built-in Thermal Protection
• Automatic Soft Start
• -40°C to +85°C Temperature Range
• TSOPJW-12 and TDFN33-12 Packages
Applications
• Cellular and Smart Phones
• Digital Still and Video Cameras
• PDAs
• Portable Devices
• Portable Media Players
• Other White LED Backlighting
Typical Application
C1
1μF
V_BATTERY
3.6V
C_IN
1μF
EN/SET
S²Cwire Serial Control
C1+
C2+
C1-
C2-
IN
OUT
AAT3340
BL1
EN/SET
BL2
BL3
BL4
GND
C2
1μF
D1 D2 D3 D4
C_OUT
1μF
3340.2008.07.1.1
www.analogictech.com
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