PRODUCT DATASHEET
AAT3169
SwitchReg
TM
High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications
Features
• V
IN
Range: 2.7V to 5.5V
• Fully Programmable Current with Single Wire
▪
16-Step Logarithmic Scale
▪
15/20/30mA Max Current
▪
Four Low-Current Settings Down to 115µA
▪
Low I
Q
(65µA) for Single-Channel, Low-Current
Mode
• Tri-Mode 1X, 1.5X, and 2X Charge Pump for Maximum
Efficiency and V
F
Coverage
• Drives Up to Six LEDs
• Individual Main-Sub (5-1) Group Control
• No Inductors, Low Noise Operation
• 1MHz Constant Switching Frequency
• Small Application Circuit
• Built-In Thermal Protection
• Built-In Auto-Disable for Open Circuit
• Automatic Soft Start
• I
Q
<1µA in Shutdown
• Thermally-Enhanced STDFN33-14 or QFN44-16
Package
General Description
The AAT3169 is a low noise, constant frequency charge
pump DC/DC converter that uses a tri-mode load switch
(1X), fractional (1.5X), and doubling (2X) conversion to
maximize efficiency for white LED applications. The
AAT3169 is capable of driving six LEDs for a total of
180mA from a 2.7V to 5.5V input. The current sinks may
be operated individually or in parallel for driving higher
current LEDs. A low external parts count (two 1µF flying
capacitors and two small 1µF capacitors at IN and
OUTCP) make this part ideally suited for small, battery-
powered applications.
AnalogicTech’s AS
2
Cwire™ (Advanced Simple Serial
Control™) serial digital input is used to enable, disable,
and set current for each LED with a 16-level logarithmic
scale plus four low-current settings down to 115µA. For
optimized efficiency, low-current settings require only
65µA of housekeeping current.
Each output of the AAT3169 is equipped with built-in
protection for output short-circuit and auto-disable for
load short-circuit conditions. Built-in soft-start circuitry
prevents excessive inrush current during start-up. A low-
current shutdown feature disconnects the load from the
input and reduces quiescent current to less than 1µA.
The AAT3169 is available in a Pb-free, space-saving,
thermally-enhanced 16-pin 4x4mm QFN package or a
low-profile 14-pin 3x3mm STDFN package and is rated
over the -40°C to +85°C temperature range.
Applications
•
•
•
•
•
Color (RGB) Lighting
Programmable Current Sink
Transmissive Displays
White LED Backlighting
White Photo Flash for Digital Still Cameras
Typical Application
C1+
C1
1µF
C2+
C2
1µF
Main
Sub
C1-
C2-
OUTCP
C
OUT
1µF
D1
D2
D3
D4
D5
D6
2.7V to 5.5V
C
IN
1µF
IN
AAT3169
D1
D2
D3
EN/SET
EN/SET
D4
D5
D6
3169.2008.03.1.3
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1
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