MAX8645X Datasheet, PDF (1/15 Pages) Maxim Integrated Products – 1x/1.5x/2x White LED Charge Pumps with Two LDOs in 4mm x 4mm TQFN

19-3978; Rev 3; 12/06
EVAALVUAAILTAIOBNLEKIT
1x/1.5x/2x White LED Charge Pumps with
Two LDOs in 4mm x 4mm TQFN
General Description
The MAX8645X/MAX8645Y charge pumps drive up to
eight white LEDs with regulated constant current for uni-
form intensity. The main group of LEDs (M1–M6) can be
driven up to 30mA per LED for backlighting. The flash
group of LEDs (F1 and F2) is independently controlled
and can be driven up to 200mA per LED (or 400mA total).
Two 200mA LDOs are on-board to provide power for
camera functions. The LDOs’ output voltages are pin pro-
grammable to meet different camera-module require-
ments. The MAX8645X and MAX8645Y differ only in LDO
output voltages. By utilizing adaptive 1x/1.5x/2x charge-
pump modes and very-low-dropout current regulators,
the MAX8645X/MAX8645Y achieve high efficiency over
the full 1-cell lithium-battery voltage range. The 1MHz
fixed-frequency switching allows for tiny external compo-
nents, and the regulation scheme is optimized to ensure
low EMI and low input ripple.
The MAX8645X/MAX8645Y are available in a 28-pin TQFN,
4mm x 4mm (0.8mm max height) lead-free package.
Applications
Camera Phones and Smartphones
Backlighting and Flash
PDAs, Digital Cameras, and Camcorders
Features
♦ Power Up to Eight 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
♦ Flexible Brightness Control
Single-Wire, Serial-Pulse Interface (32 Steps)
2-Bit Logic (Three Levels)
♦ 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 TQFN, 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 580mA
10μF
MAIN FLASH
MAX8645X
GND
MAX8645Y
M1
PGND
M2
M3
M4
ENM1
M5
ENM2
M6
F1
ENF
F2
ENLDO
LDO1
LDO2
P1
1μF
P2
SETM SETF REF
0.01μF
CAMERA
MODULE
1μF
Ordering Information
PART
TEMP RANGE
PIN-
PACKAGE
MAX8645XETI+
-40°C to +85°C
28 TQFN-EP
4mm x 4mm
MAX8645YETI+ -40°C to +85°C
EP = Exposed paddle.
+Denotes a lead-free package.
28 TQFN-EP
4mm x 4mm
PKG
CODE
T2844-1
T2844-1
Pin Configuration appears at end of data sheet.
________________________________________________________________ Maxim Integrated Products 1
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