AAT3340
High Efficiency 1x/1.5x Charge PumpChargePump
TM
PRODUCT DATASHEET
3340.2008.07.1.1 1
www.analogictech.com
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 1F flying capacitors
and two small 1F capacitors at V
IN
and V
OUT
) makes the
AAT3340 ideal for small battery-powered applications.
Analogic Tech’s Simple Serial Control (S
2
Cwire) 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.
Features
•
Dual-Mode (1x/1.5x) Charge Pump
•
Drives up to 4-Channel Backlight LEDs
•
32-Level Programmable Backlight Current (linear,
inverting)
•
Single-wire S
2
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
V
BATTERY
3.6V
EN/SET
S
2
Cwire Serial Control
IN
EN/SET
C2+
C2-
C1+
C1-
OUT
BL1
BL2
BL3
GND
C
IN
1μF
D1
C1
1μF
C2
1μF
D2 D3 D4
C
OUT
1μF
BL4
AAT3340
