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PDF MAX8645X Data sheet ( Hoja de datos )
| Número de pieza | MAX8645X | |
| Descripción | (MAX8645X/Y) 1x/1.5x/2x White LED Charge Pumps | |
| Fabricantes | Maxim Integrated Products | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de MAX8645X (archivo pdf) en la parte inferior de esta página. Total 15 Páginas | ||
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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.
www.DataSheet4U.com
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 (PLED/PBATT) 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 TA 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
GND
PGND
MAX8645X
MAX8645Y
ENM1
ENM2
ENF
ENLDO
P1
M1
M2
M3
M4
M5
M6
F1
F2
LDO1
LDO2
P2
SETM SETF
REF
0.01μF
1μF
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
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.
1 page  
1x/1.5x/2x White LED Charge Pumps with
Two LDOs in 4mm x 4mm TQFN
Typical Operating Characteristics (continued)
(VIN = VEN_ = 3.6V, circuit of Figure 2, TA = +25°C, unless otherwise noted.)
www.DataSheet4U.com
BATTERY CURRENT vs. SUPPLY
VOLTAGE DRIVING FLASH
900
800
700
600 IFLASH = 400mA
500
400 IFLASH = 160mA
300
IFLASH = 80mA
200
100
0
2.7 3.0 3.3 3.6 3.9 4.2
SUPPLY VOLTAGE (V)
INPUT RIPPLE VOLTAGE vs. SUPPLY
VOLTAGE WITH FLASH AND MAIN LEDs
10
9 FOUR MAIN LEDs AT 15mA EACH
8 IFLASH = 40mA
7 IFLASH = 160mA
6 IFLASH = 400mA
5
4
3
2
1
0
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
SUPPLY VOLTAGE (V)
LDO GROUND-PIN SUPPLY
CURRENT vs. SUPPLY VOLTAGE
160
VENM_ = VENF = 0V, VENLDO = VIN
150
140
130 NO LOAD, BOTH LDOs 150mA, BOTH LDOs
120
110
100
90
80
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
SUPPLY VOLTAGE (V)
LED CURRENT MATCHING vs. SUPPLY
VOLTAGE WITH SIX MAIN LEDs
16.0
15.8
15.6
15.4
15.2
15.0
14.8
14.6
14.4
14.2
14.0
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
SUPPLY VOLTAGE (V)
INPUT RIPPLE VOLTAGE vs. SUPPLY
VOLTAGE WITH SIX MAIN LEDs
1.8
1.5 ILED = 15mA
1.2
0.9
ILED = 4.5mA
0.6
ILED = 1.5mA
0.3
0
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
SUPPLY VOLTAGE (V)
LED CURRENT MATCHING vs. SUPPLY
VOLTAGE WITH TWO FLASH LEDs
102.0
101.5
101.0
100.5
100.0
99.5
99.0
98.5
98.0
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
SUPPLY VOLTAGE (V)
LED CURRENT vs. AMBIENT
TEMPERATURE WITH SIX MAIN LEDs
105
90
75
60
45
30
15
0
-40 -15 10 35 60 85
TA (°C)
450
400
350
300
250
200
150
100
50
0
-40
LED CURRENT vs. AMBIENT
TEMPERATURE WITH FLASH
-15 10
35
TA (°C)
60
85
INDIVIDUAL MAIN LED CURRENT
vs. RSETM
100
10
1
1 10 100
RSETM (kΩ)
_______________________________________________________________________________________ 5
5 Page 
1x/1.5x/2x White LED Charge Pumps with Two
LDOs in 4mm x 4mm TQFN
C3 C4
1μF 1μF
www.DataSheet4U.com
INPUT
2.7V TO 5.5V
C1
10μF
C1P
PIN
IN
GND
C1N
C2P C2N
LDO1
LDO2
ON
OFF
ENM2
MAX8645X
MAX8645Y
OUT
PWM INPUT
ON/OFF
ON/OFF
VOLTAGE
SELECTION
ENM1
ENF
ENLDO
P1
P2
M1
M2
M3
M4
M5
M6
F1
F2
SETM SETF REFBP
PGND
RSETM
RSETF
6.81kΩ 4.12kΩ
C8
0.01μF
Figure 2. Dimming Using PWM Signal into ENM1
1μF 1μF
C6
1μF
C7
1μF OUTPUT
UP TO 480mA
C5
10μF
MAIN
FLASH
INPUT
2.7V TO 5.5V
10μF
C1P
PIN
IN
GND
C1N
C2P C2N
LDO1
LDO2
ON/OFF AND
VOLTAGE
SELECTION
ENM2
MAX8645X
MAX8645Y
OUT
ENM1
ENF
ENLDO
P1
P2
SETM SETF REFBP
M1
M2
M3
M4
M5
M6
F1
F2
PGND
6.81kΩ 4.12kΩ
0.01μF
1μF
1μF
OUTPUT
UP TO 480mA
10μF MAIN
FLASH
Figure 3. Providing Increased LED Current per LED
______________________________________________________________________________________ 11
11 Page | ||
| Páginas | Total 15 Páginas | |
| PDF Descargar | [ Datasheet MAX8645X.PDF ] | |
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