CAT3648HV3-GT2 Datasheet, PDF (1/14 Pages) ON Semiconductor – 4-Channel Ultra High Efficiency Quad-Mode LED Driver with 32 Dimming Levels

4-Channel Ultra High Efficiency Quad-Mode^®
LED Driver with 32 Dimming Levels
CAT3648
FEATURES
„ High efficiency 1.33x charge pump
„ Quad-mode charge pump: 1x, 1.33x, 1.5x, 2x
„ Drives up to 4 LEDs at 25mA 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
„ 3mm x 3mm, 16-pad TQFN package
APPLICATION
„ LCD Display Backlight
„ Cellular Phones
„ Digital Still Cameras
„ Handheld Devices
ORDERING INFORMATION
Part Number
Qty per Reel
CAT3648HV3-GT2
2000 ⁽¹⁾
Marking
JAAN
Notes: (1) NiPdAu Plated Finish (RoHS-compliant)
PIN CONFIGURATION
(Top View)
DESCRIPTION
The CAT3648 is a high efficiency quad-mode
fractional charge pump that can drive up to four 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 tradi–
tional 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 2.5V to 5.5V.
The EN/DIM logic input functions as a chip enable and
a digital dimming interface for setting the current in all
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.
Catalyst Semiconductor’s Quad-Mode^® 1.33x, charge
pump switching architecture is patented.
TYPICAL APPLICATION CIRCUIT
1µF
1µF
V_IN
2.4V ^CIN
to
5.5V ^1µF
1-Wire
EZDim^TM
Programming
3.74kΩ
C1+
VIN
C1- C2+
C2-
VOUT
CAT3648
EN/DIM
RSET
GND
LED1
LED2
LED3
LED4
V_OUT
C_OUT
1µF
20mA
© 2008 SCILLC. All rights reserved.
1
Characteristics subject to change without notice
Doc. No. MD-5031, Rev. C