CAT3643 Datasheet, PDF (1/17 Pages) Catalyst Semiconductor – 3-Channel Ultra High Efficiency Quad-Mode TM LED Driver

CAT3643
3-Channel Ultra High Efficiency Quad-Mode™
LED Driver
FEATURES
„ High efficiency 1.33x charge pump
„ Quad-mode charge pump: 1x, 1.33x, 1.5x, 2x
„ Drives up to 3 LEDs at 32mA each
„ 1-wire EZDim™ LED current programming
„ 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
„ Tiny 12-lead XQFN, 12-lead TDFN and 16-lead
TQFN packages
APPLICATION
„ LCD Display Backlight
„ Cellular Phones
„ Digital Still Cameras
„ Handheld Devices
ORDERING INFORMATION
Part
Number
Package
Package
Marking
CAT3643HV2-T2 TDFN-12 3 x 3mm⁽¹⁾ HABF
CAT3643HV3-T2 TQFN-16 3 x 3mm⁽¹⁾ JAAE
CAT3643HL1-T2 XQFN-12 2.5 x 2.5mm⁽¹⁾ LB
Notes:
(1) Matte-Tin Plated Finish (RoHS-compliant)
(2) Quantity per reel is 2000
For Ordering Information details, see page 16.
DESCRIPTION
The CAT3643 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 current setting of all
LEDs. Six different current ratios are available via the
interface.
The device is available in the tiny 12-lead XQFN 2.5 x
2.5mm with max height of 0.4mm or in 16-lead TQFN
or 12-lead TDFN 3mm x 3mm package with a max
height of 0.8mm.
The 1.33x charge pump architecture with two fly
capacitors is patent pending.
TYPICAL APPLICATION CIRCUIT
1µF
1µF
V_IN
2.4V ^CIN
to
5.5V ^1µF
1-Wire
EZDim^TM
Programming
3.8kΩ
C1+
V_IN
C1- C2+
C2-
V_OUT
White LEDs
CAT3643
EN/DIM
RSET
GND
LED1
LED2
LED3
V_OUT
C_OUT
1µF
20mA
© 2007 Catalyst Semiconductor, Inc.
1
Characteristics subject to change without notice
Doc. No. 5022, Rev. B