CAT3606 Datasheet, PDF (1/11 Pages) Catalyst Semiconductor – 6-Channel Low Noise Charge Pump White LED Driver

CAT3606
6-Channel Low Noise Charge Pump White LED Driver
FEATURES
I Drives up to 4 main LEDs and 2 sub LEDs
I Separate control for main and sub LEDs
I Compatible with supply voltage of 3V to 5.5V
I Power efficiency up to 90%
I Output current up to 30mA per LED
I High-frequency Operation at 1MHz
I 2 modes of operation 1x and 1.5x
I White LED detect circuitry on all channels
I Shutdown current less than 1µA
I Small ceramic capacitors
I Soft start and current limiting
I Short circuit protection
I 16-lead thin QFN package, 0.8mm
max height
APPLICATIONS
I Cell phone main and sub-display backlight
I Navigation
I PDAs
I Digital Cameras
DESCRIPTION
The CAT3606 controls up to four LEDs for the main
display and two LEDs for the sub-display in cellular
phones. The device is capable of operating in either
1x (LDO) mode or 1.5x charge pump mode. All LED
pin currents are regulated and tightly matched to
achieve uniformity of brightness across the LCD
backlight. An external resistor (R_SET) sets the
nominal output current.
The device can deliver as much as 20mA per
channel during low voltage operation (3V), and
30mA per channel during nominal operation (3.3V).
A constant high-frequency switching scheme
(1MHz) provides low noise and allows the use of
very small value ceramic capacitors.
A “zero” quiescent current mode can be achieved
via the chip enable pin EN. The Main and Sub LEDs
each have their own dedicated ON/OFF control
pins (ENM, ENS). Dimming can be achieved using
either a DC voltage to control the R_SET pin current,
or by applying a PWM signal on the ENM and ENS
pins.
The device is available in a 16-lead thin QFN
package with a max height of 0.8mm.
TYPICAL APPLICATION CIRCUIT
Li-Ion
Battery ₊
-
CIN
ON/OFF
ENABLE
LED1-4
ENABLE
LED5-6
RSET
C1+ C1- C2+ C2-
VIN
VOUT
CAT3606
EN
LED1
ENM
LED2
LED3
ENS
LED4
RSET
GND
LED5
LED6
Main Display
Sub Display
COUT
20mA
© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. 5009, Rev. B