19-3744; Rev 0; 7/05
IT
EVALUATION K
AVAILABLE
Light-Management IC with Efficient 1x/1.5x/2x
Charge Pump for Backlight/Flash/RGB LEDs
General Description
The MAX1707 provides complete light management for
main display backlight, subdisplay backlight (or RGB
indicator), and white LED camera flash with regulated
constant current up to 610mA total. By utilizing adap-
tive 1x/1.5x/2x charge-pump modes and very-low-
dropout current regulators, it achieves high efficiency
over the full 1-cell Li+ battery input voltage range. The
1MHz fixed-frequency switching allows for tiny external
components while the regulation scheme is optimized
to ensure low EMI and low input ripple. An integrated
derating function protects the LEDs from overheating
during high ambient temperatures.
The MAX1707 features an internally trimmed reference
to set the maximum LED current. An I
2
C
†
serial port is
used for on/off control and setting the LED currents in
32 linear steps. When using the RGB indicator, the I
2
C
port provides 32k colors and programmable ramp-
up/down rates. The camera flash may be turned on/off
by the I
2
C port or a separate digital logic input.
Features
♦
Guaranteed 610mA Continuous Drive Capability
4 LEDs at 30mA Each for Main Display
3 LEDs at 30mA Each for Sub or RGB
400mA Total for Flash
♦
2-Wire I
2
C Serial Port
5-Bit (32-Step) Linear Dimming
32k Colors
Ramp-Up/Down Rates
♦
92% Peak/83% Avg Efficiency (P
LED
/P
BATT
)
♦
Adaptive 1x/1.5x/2x Mode Switchover
♦
0.3% (typ) LED Current Accuracy and Matching
♦
Low Input Ripple and EMI
♦
Low 0.1µA Shutdown Current
♦
Output Overvoltage Protection
♦
Thermal Derating Function Protects LEDs
♦
24-Pin 4mm x 4mm Thin QFN Package
MAX1707
Applications
Cell Phones and Smartphones
PDAs, Digital Cameras, Camcorders
Displays with Up to 11 LEDs
†
Purchase of I
2
C components from Maxim Integrated Products,
Ordering Information
PART
MAX1707ETG
TEMP RANGE
-40°C to +85°C
PIN-
PACKAGE
24 Thin QFN
4mm x 4mm
PKG
CODE
T2444-4
Inc., or one of its sublicensed Associated Companies, conveys
a license under the Philips I
2
C Patent Rights to use these com-
ponents in an I
2
C system, provided that the system conforms to
the I
2
C Standard Specification as defined by Philips.
Pin Configuration appears at end of data sheet.
Typical Operating Circuit
1µF
INPUT
2.7V TO 5.5V
4.7µF
1µF
OUTPUT
UP TO 610mA
10µF
MAIN
SUB OR RGB
FLASH
C1P
IN
PIN
GND
C1N
C2P
C2N
OUT
MAX1707
V
LOGIC
0.1µF
V
DD
I
2
C PORT
ON/OFF AND
BRIGHTNESS
STROBE
ON/OFF
SCK
SDA
STB
PGND
M1
M2
M3
M4
S1
S2
S3
F1
F2
F3
F4
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
