19-3688; Rev 3; 6/08
KIT
ATION
EVALU
E
BL
AVAILA
1x/1.5x/2x White LED Charge Pump with
Two LDOs in 4mm x 4mm Thin QFN
General Description
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
MAX8631X/Y
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
Typical Operating Circuit
1μF
INPUT
2.7V TO 5.5V
1μF
OUTPUT
UP TO 480mA
10μF
MAX8631X/Y
M1
M2
M3
M4
F1
F2
F3
F4
LDO1
LDO2
1μF
SETM
SETF
REF
0.01μF
1μF
CAMERA
MODULE
MAIN
FLASH
Ordering Information
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 Thin QFN-EP*
4mm x 4mm (T2844-1)
28 Thin QFN-EP*
4mm x 4mm (T2844-1)
C1P
PIN
IN
C1N
C2P
C2N
OUT
MAX8631XETI+
MAX8631YETI+
10μF
GND
PGND
*EP
= Exposed pad.
+Denotes
a lead-free package.
MAIN ON/OFF
AND DIMMING
FLASH ON/OFF
DUAL-LDO ON/OFF
DUAL-LDO
VOLTAGE
SELECTION
ENM1
ENM2
ENF
ENLDO
P1
P2
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.
1x/1.5x/2x White LED Charge Pump with Two
LDOs in 4mm x 4mm Thin QFN
MAX8631X/Y
ABSOLUTE MAXIMUM RATINGS
PIN, IN, OUT, REFBP to GND................................-0.3V to +6.0V
SETF, SETM, ENLDO, ENM1, ENM2, ENF,
P1, P2, LDO1, LDO2 to GND....................-0.3V to (V
IN
+ 0.3V)
M1, M2, M3, M4, F1, F2, F3, F4 to GND...-0.3V to (V
OUT
+ 0.3V)
C1N, C2N to GND ......................................... -0.3V to (V
IN
+ 1V)
C1P, C2P
to GND.............. -0.3V to greater of (V
OUT
+ 1V) or (V
IN
+ 1V)
PGND to GND .......................................................-0.3V to +0.3V
OUT, LDO1, LDO2 Short-Circuit to GND ...................Continuous
Continuous Power Dissipation (T
A
= +70°C)
28-Pin Thin QFN 4mm X 4mm
(derate 20.8mW/°C above +70°C) .............................1666mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
IN
= 3.6V, V
GND
= V
PGND
= 0V, ENM1 = ENM2 = ENF = IN, R
SETM
= R
SETF
= 6.8kΩ, P1 = P2 = unconnected, C
REF
= 0.01µF,
T
A
= -40°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
IN Operating Voltage
Undervoltage-Lockout Threshold
Undervoltage-Lockout Hysteresis
1MHz switching, no load, 1.5x or 2x mode
Supply Current
1x mode 10% setting, ENF = GND, V
ENLDO
= V
IN
,
I
LDO1
= I
LDO2
= 0A
ENM1 = ENM2 = ENF = GND, V
ENLDO
= V
IN
,
I
LDO1
= I
LDO2
= 0A
Shutdown Supply Current
EN_ High Voltage
EN_ Low Voltage
EN_ Input Current
ENM_ or ENF Low Shutdown
Delay t
SHDN
ENM_ or ENF t
LO
ENM_ or ENF t
HI
Initial ENM_ or ENF t
HI
P1, P2 Shutdown Input Current
P1, P2 Input Impedance
Thermal-Shutdown Threshold
Thermal-Shutdown Hysteresis
CHARGE PUMP
Overvoltage-Protection Threshold
Soft-Start Time
V
OUT
rising
5
2
V
ms
Temperature rising
ENM1 = ENM2 = ENF = ENLDO = GND
V
IN
= 2.7V to 5.5V
V
IN
= 2.7V to 5.5V
V
EN_
= 0V or 5.5V
See Figure 2
See Figure 2
See Figure 2
Only required for first ENM_ or ENF pulse, see Figure 2
T
A
= +25°C
T
A
= +85°C
2.5
0.5
0.5
200
1
150
+160
20
250.0
0.01
0.1
T
A
= +25°C
T
A
= +85°C
1.4
0.4
1
V
IN
rising or falling
CONDITIONS
MIN
2.7
2.25
2.45
130
4.0
0.4
110
0.01
0.1
5
5.5
mA
TYP
MAX
5.5
2.60
UNITS
V
V
mV
µA
µA
V
V
µA
ms
µs
µs
µs
µA
kΩ
°C
°C
2
_______________________________________________________________________________________
1x/1.5x/2x White LED Charge Pump with Two
LDOs in 4mm x 4mm Thin QFN
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 3.6V, V
GND
= V
PGND
= 0V, ENM1 = ENM2 = ENF = IN, R
SETM
= R
SETF
= 6.8kΩ, P1 = P2 = unconnected, C
REF
= 0.01µF,
T
A
= -40°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
1x to 1.5x or 1.5x to 2x Mode
Transition Threshold
Input Voltage-Mode Transition
Hysteresis
Charge-Pump Maximum OUT
Current
Open-Loop OUT Resistance
Charge-Pump Short-Circuit
Current
Switching Frequency
OUT Pulldown Resistance in
Shutdown
LED DRIVER
SET_ Bias Voltage
SET_ Leakage in Shutdown
SET_ Current Range
SETM-to-Main LED Current Ratio
(I
M_
/I
SETM
)
SETF-to-Flash LED Current Ratio
(I
F_
/I
SETF
)
M_, F_ Current Accuracy
Maximum Main LED Sink Current
Maximum Flash LED Sink Current
Current-Derating-Function Start
Temperature
Current-Derating-Function Slope
Dropout Voltage
1.5x and 2x Regulation Voltage
M_, F_ Leakage in Shutdown
LDO_
Output Voltage Accuracy
Output Current Range
Current Limit
Soft-Start Current Limit
V
LDO_
= 0V
ENM_ = ENF = GND
T
A
= +25°C
T
A
= +85°C
-1.7
0
280
475
160
T
A
= +40°C to +85°C
(Note 2)
100% setting, M1–M4
100% setting, F1–F4
T
A
= +25°C
T
A
= -40°C to current derating start temperature
R
SETM
= 4.6kΩ, for each M_
R
SETF
= 4.12kΩ, I
F1
+ I
F2
+ I
F3
+ I
F4
-1.25
-4
30
400
+40
-1.7
40
150
0.01
0.1
0
+1.7
200
750
1
90
T
A
= +25°C
ENM_ = ENF = GND
T
A
= +25°C
T
A
= +85°C
10
230
690
+1.25
+4
0.6
0.01
0.1
145
1
V
µA
µA
A/A
A/A
%
mA
mA
°C
%/°C
mV
mV
µA
V
IN
≥
3.15V, V
OUT
= 3.9V
1x mode, (V
IN
- V
OUT
) / I
OUT
1.5x mode, (1.5V
IN
- V
OUT
) / I
OUT
2x mode, (2V
IN
- V
OUT
) / I
OUT
V
OUT
< 1.25V
580
0.3
1.1
1.5
500
1
ENM_ = ENF = GND
5
1.0
4.0
4.14
mA
MHz
kΩ
Ω
CONDITIONS
MIN
90
TYP
100
150
MAX
110
UNITS
mV
mV
mA
MAX8631X/Y
I
LDO_
= 150mA, relative to V
OUT(NOM)
(Note 3)
%
mA
mA
mA
_______________________________________________________________________________________
3
1x/1.5x/2x White LED Charge Pump with
Two LDOs in 4mm x 4mm Thin QFN
MAX8631X/Y
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 3.6V, V
GND
= V
PGND
= 0V, ENM1 = ENM2 = ENF = IN, R
SETM
= R
SETF
= 6.8kΩ, P1 = P2 = unconnected, C
REF
= 0.01µF,
T
A
= -40°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Soft-Start Done Time
Dropout Voltage
Load Regulation
Power-Supply Rejection
ΔV
OUT
/ΔV
IN
Output Noise Voltage (RMS)
I
LDO_
= 200mA (Note 4)
V
IN
= 3.7V, 100µA < I
LDO_
< 200mA
10Hz to 10kHz, C
LDO_
= 1µF, I
LDO_
= 10µA
10Hz to 100kHz, C
LDO_
= 1µF, I
LDO_
= 10mA
-60
40
CONDITIONS
MIN
TYP
100
120
320
1.3
MAX
UNITS
µs
mV
%
dB
µV
RMS
Note 1:
All devices are 100% production tested at T
A
= +25°C. Limits over the operating temperature range are guaranteed by
design.
Note 2:
LED dropout voltage is defined as the M_ or F_ to GND voltage at which current into M_ or F_ drops 10% from the value at
M_ or F_ = 0.2V.
Note 3:
(Greater of 2.7V or (V
LDO_
+ 0.5V))
≤
V
IN
≤
5.5V.
Note 4:
LDO dropout voltage is defined as V
IN
- V
OUT
when V
OUT
is 100mV below the value of V
OUT
measured when V
IN
=
V
OUT(NOM)
+ 1V. Since the minimum input voltage is 2.7V, this specification is only meaningful when V
OUT(NOM)
> 2.5V.
Typical Operating Characteristics
(V
IN
= V
EN_
= 3.6V, circuit of Figure 1, T
A
= +25°C, unless otherwise noted.)
EFFICIENCY vs. Li+ BATTERY
VOLTAGE DRIVING FOUR MAIN LEDs
MAX8631X toc01
EFFICIENCY vs. Li+ BATTERY
VOLTAGE DRIVING FLASH LED MODULE
MAX8631 toc02
BATTERY CURRENT vs. SUPPLY VOLTAGE
DRIVING FOUR MAIN LEDs
I
LED
= 15mA
100
BATTERY CURRENT (mA)
80
60
I
LED
= 4.5mA
40
20
0
I
LED
= 1.5mA
V
IN
FALLING
V
IN
RISING
MAX8631X toc03
100
90
EFFICIENCY P
LED
/P
BATT
(%)
80
70
15mA/LED
60
50
40
2.7
3.0
3.3
3.6
3.9
4.5mA/LED
1.5mA/LED
100
80mA TOTAL
90
EFFICIENCY P
LED
/P
BATT
(%)
80
70
60
50
40
400mA TOTAL
160mA TOTAL
120
4.2
2.7
3.0
3.3
3.6
3.9
4.2
2.7
3.0
3.3
3.6
3.9
4.2
Li+ BATTERY VOLTAGE (V)
Li+ BATTERY VOLTAGE (V)
SUPPLY VOLTAGE (V)
4
_______________________________________________________________________________________
1x/1.5x/2x White LED Charge Pump with
Two LDOs in 4mm x 4mm Thin QFN
Typical Operating Characteristics (continued)
(V
IN
= V
EN_
= 3.6V, circuit of Figure 1, T
A
= +25°C, unless otherwise noted.)
BATTERY CURRENT vs. SUPPLY
VOLTAGE DRIVING FLASH
MAX8631X toc04
MAX8631X/Y
LDO GROUND PIN SUPPLY
CURRENT vs. SUPPLY VOLTAGE
MAX8631X toc05
INPUT RIPPLE VOLTAGE vs. SUPPLY
VOLTAGE WITH FOUR MAIN LEDs
MAX8631X toc06
900
800
BATTERY CURRENT (mA)
700
600
500
400
300
200
100
0
2.7
3.0
3.3
3.6
3.9
I
FLASH
= 160mA
I
FLASH
= 80mA
I
FLASH
= 400mA
160
GROUND PIN SUPPLY CURRENT (μA)
150
140
130
120
110
100
90
80
2.7
3.1
3.5
3.9
4.3
4.7
5.1
NO LOAD, BOTH LDOs
150mA, BOTH LDOs
V
ENM
= V
ENF
= 0V, V
ENLDO
= V
IN
1.2
1.0
INPUT RIPPLE (mV
RMS
)
0.8
0.6
I
LED
= 4.5mA
0.4
I
LED
= 1.5mA
0.2
0
I
LED
= 15mA
4.2
5.5
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
INPUT RIPPLE VOLTAGE vs. SUPPLY
VOLTAGE WITH FLASH AND MAIN LEDs
9
8
INPUT RIPPLE (mV
RMS
)
7
6
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)
FOUR MAIN LEDs AT 15mA EACH
I
FLASH
= 10mA
I
FLASH
= 40mA
I
FLASH
= 100mA
MAX8631X toc07
LED CURRENT MATCHING vs. SUPPLY
VOLTAGE WITH FOUR MAIN LEDs
15.8
MAIN LED CURRENT (mA)
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)
MAX8631X toc08
LED CURRENT MATCHING vs. SUPPLY
VOLTAGE WITH FOUR FLASH LEDs
101.5
FLASH LED CURRENT (mA)
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)
MAX8631X toc09
10
16.0
102.0
LED CURRENT vs. AMBIENT
TEMPERATURE WITH FOUR MAIN LEDs
MAX8631X toc10
LED CURRENT vs. AMBIENT
TEMPERATURE WITH FLASH
MAX8631X toc11
INDIVIDUAL MAIN LED CURRENT
vs. R
SETM
MAX8631X toc12
70
60
TOTAL LED CURRENT (mA)
50
40
30
20
10
0
-40
-15
10
35
60
450
400
TOTAL LED CURRENT (mA)
350
300
250
200
150
100
50
0
100
MAIN LED CURRENT (mA)
-40
-15
10
35
60
85
10
1
1
10
R
SETM
(kΩ)
100
AMBIENT TEMPERATURE (°C)
85
AMBIENT TEMPERATURE (°C)
_______________________________________________________________________________________
5
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