MAX8631_08 Datasheet, PDF (1/15 Pages) Maxim Integrated Products – 1x/1.5x/2x White LED Charge Pump with Two LDOs in 4mm x 4mm Thin QFN

19-3688; Rev 3; 6/08
EVAALVUAAILTAIOBNLEKIT
1x/1.5x/2x White LED Charge Pump with
Two LDOs in 4mm x 4mm Thin QFN
General Description
The MAX8631X/Y charge pump drives up to eight white
LEDs with regulated constant current for uniform inten-
sity. The main group of LEDs (M1–M4) can be driven
up to 30mA per LED for backlighting. The flash group
of LEDs (F1–F4) is independently controlled and can be
driven up to 100mA per LED (or 400mA total). Two
200mA LDOs are on-board to provide power for cam-
era functions. The LDOs’ output voltages are pin-pro-
grammable to meet different camera-module
requirements. By utilizing adaptive 1x/1.5x/2x charge-
pump modes and very-low-dropout current regulators,
the MAX8631X/Y achieves high efficiency over the full
1-cell lithium-battery voltage range. The 1MHz fixed-fre-
quency switching allows for tiny external components,
and the regulation scheme is optimized to ensure low
EMI and low input ripple.
The MAX8631X/Y is available in a 28-pin thin QFN,
4mm x 4mm lead-free package (0.8mm max height).
Applications
Camera Phones and Smartphones
Backlighting and Flash
PDAs, Digital Cameras, and Camcorders
Features
♦ Powers Up to 8 LEDs
Up to 30mA/LED Drive for Backlight
Up to 400mA Total Drive for Flash
♦ Two Internal Low-Noise 200mA LDOs
♦ 94% Max/85% Avg Efficiency (P_LED/P_BATT) over Li+
Battery Discharge
♦ 0.2% Typical LED Current Matching
♦ Adaptive 1x/1.5x/2x Mode Switchover
♦ Single-Wire Serial Pulse Interface for Brightness
Control (32 Steps)
♦ Thermal T_A Derating Function
♦ Low Input Ripple and EMI
♦ 2.7V to 5.5V Supply Voltage Range
♦ Soft-Start, Overvoltage, and Thermal-Shutdown
Protection
♦ 28-Pin Thin QFN, 4mm x 4mm Package
Typical Operating Circuit
1μF
1μF
INPUT
2.7V TO 5.5V
10μF
MAIN ON/OFF
AND DIMMING
FLASH ON/OFF
DUAL-LDO ON/OFF
DUAL-LDO
VOLTAGE
SELECTION
C1P C1N
PIN
IN
C2P C2N
OUT
OUTPUT
UP TO 480mA
10μF
MAIN
FLASH
MAX8631X/Y
GND
M1
PGND
M2
M3
M4
ENM1
F1
ENM2
F2
F3
ENF
F4
ENLDO
LDO1
LDO2
P1
1μF
P2
SETM SETF REF
0.01μF
CAMERA
MODULE
1μF
Ordering Information
PART
MAX8631XETI+
TEMP RANGE
-40°C to +85°C
MAX8631YETI+ -40°C to +85°C
*EP = Exposed pad.
+Denotes a lead-free package.
PIN-PACKAGE
28 Thin QFN-EP*
4mm x 4mm (T2844-1)
28 Thin QFN-EP*
4mm x 4mm (T2844-1)
Pin Configuration appears at end of data sheet.
________________________________________________________________ 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.