MAX8647 Datasheet, PDF (1/15 Pages) Maxim Integrated Products – Ultra-Efficient Charge Pumps for Six White/RGB LEDs in 3mm x 3mm Thin QFN

19-0790; Rev 0; 4/07
EVAALVUAAILTAIOBNLEKIT
Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFN
General Description
The MAX8647/MAX8648 drive up to six white LEDs or
two sets of RGB LEDs with regulated constant current
for display backlight and fun light applications. By utiliz-
ing an inverting charge pump and extremely low-
dropout adaptive current regulators, these ICs achieve
very high efficiency over the full 1-cell Li+ battery volt-
age range and even with large LED forward voltage
mismatch. The 1MHz fixed-frequency switching allows
for tiny external components. The regulation scheme is
optimized to ensure low EMI and low input ripple. The
MAX8647/MAX8648 include thermal shutdown, open-
and short-circuit protection.
The MAX8647 features an I²C serial port, while the
MAX8648 features a three-wire serial-pulse logic inter-
face. Both devices support independent on/off and
dimming for main and subbacklights. The dimming
ranges are pseudo-logarithmic from 24mA to 0.1mA
and off in 32 steps. Both devices include a temperature
derating function to safely allow bright 24mA full-scale
output current setting while automatically reducing cur-
rent to protect LEDs at high ambient temperatures
above +60°C.
The MAX8647/MAX8648 are available in a 16-pin, 3mm
x 3mm thin QFN package (0.8mm max height).
Applications
White LED Backlighting, Single or Dual Display
Wide-Gamut RGB LED Display Backlighting
Camera Flash or RGB Indicators
Cellular Phones and Smartphones
PDAs, Digital Cameras, and Camcorders
Pin Configuration
TOP VIEW
12 11 10 9
LED1 13
SDA (ENC) 14
SCL (ENB) 15
MAX8647ETE
MAX8648ETE
V_DD (ENA) 16 ₊
1234
8 LED6
7 NEG
6 C1N
5 C2N
THIN QFN
( ) DESIGNATE PINS ON THE MAX8648
Features
♦ Six Adaptive Current Regulators
♦ Independent Voltage Supply for Each LED
♦ Individual LED Brightness Control (MAX8647)
♦ 24mA to 0.1mA Dimming Range
I²C Interface (MAX8647)
Serial-Pulse Dimming Logic (MAX8648)
♦ ±2% Accuracy, ±0.4% Matching (typ)
♦ Low 70µA Quiescent Current
♦ Low 1µA Shutdown Current
♦ Inrush Current Limit
♦ T_A Derating Function Protects LEDs
♦ 16-Pin, 3mm x 3mm Thin QFN Package
Ordering Information
PART
DIMMING
PIN
PACKAGE
TOP PKG
MARK CODE
MAX8647ETE+ I²C interface 16 Thin QFN-EP* AFD T1633-5
MAX8648ETE+
Serial-pulse
logic
16 Thin QFN-EP*
AFE
T1633- 5
Note: All devices are specified over the -40°C to +85°C extended
temperature range.
+Denotes a lead-free package.
*EP = Exposed paddle.
Typical Operating Circuit
INPUT
2.7V TO 5.5V
1μF
SERIAL-
PULSE
INTERFACE
1μF
1μF
C1P
IN
GND
C1N C2P
C2N
NEG
EP
MAX8648
LED1
LED2
ENA
LED3
ENB
LED4
ENC
LED5
LED6
1μF
WHITE
OR RGB LED
D1
D2
D3
D4
D5
D6
________________________________________________________________ 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.