CAT3647
3-Channel Ultra High Efficiency Quad-Mode™
LED Driver with 32 Dimming Levels
FEATURES
High efficiency 1.33x charge pump
Quad-mode charge pump: 1x, 1.33x, 1.5x, 2x
Drives up to 3 LEDs at 30mA each
1-wire EZDim™ 32 linear steps
Power efficiency up to 92%
Low noise input ripple in all modes
“Zero” current shutdown mode
Soft start and current limiting
Short circuit protection
Thermal shutdown protection
RoHS-compliant 16-pad TQFN package
DESCRIPTION
The CAT3647 is a high efficiency quad-mode
fractional charge pump that can drive up to three
LEDs programmable by a one wire digital interface.
The inclusion of a 1.33x fractional charge pump mode
increases device efficiency by up to 10% over
traditional 1.5x charge pumps with no added external
capacitors.
Low noise input ripple is achieved by operating at a
constant switching frequency which allows the use of
small external ceramic capacitors. The multi-fractional
charge pump supports a wide range of input voltages
from 2.4V to 5.5V.
The EN/DIM logic input functions as a chip enable and
a digital dimming interface for setting the current in all
the LED channels. The 1-wire pulse-dimming interface
supports 32 linear steps from full-scale down to zero
current.
The device is available in the tiny 16-pad TQFN 3mm
x 3mm package with a max height of 0.8mm.
Marking
JAAP
Catalyst Semiconductor’s Quad-Mode™ 1.33x,
charge pump switching architecture is patented.
APPLICATION
LCD Display Backlight
Cellular Phones
Digital Still Cameras
Handheld Devices
ORDERING INFORMATION
Part Number
CAT3647HV3-GT2
Package
TQFN-16
3mm x 3mm
(1)
Notes:
(1) NiPdAu Plated Finish (RoHS-compliant)
(2) Quantity per reel is 2000
PIN CONFIGURATION
(Top View)
LED1
GND
NC
NC
TYPICAL APPLICATION CIRCUIT
1µF
1µF
16
LED2
LED3
NC
RSET
1
2
3
4
5
EN/DIM
15
14
13
12 C2-
11 C2+
10 C1-
9 C1+
V
IN
2.4V
to
5.5V
C
IN
1µF
C1+
VIN
C1- C2+
C2-
VOUT
V
OUT
C
OUT
CAT3647
EN/DIM
RSET
LED1
LED2
GND
LED3
1µF
1-Wire
EZDim
TM
Programming
3.74kΩ
20mA
6
VOUT
7
NC
8
VIN
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. MD-5030 Rev. A
CATALYST [ CATALYST SEMICONDUCTOR ]
