MAXIM MAX8631X, MAX8631Y Technical data

EVALUATION KIT

AVAILABLE

General Description

The MAX8631X/Y charge pump drives up to eight white
LEDs with regulated constant current for uniform inten­sity. 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 cam­era functions. The LDOs’ output voltages are pin-pro­grammable to meet different camera-module
requirements. By utilizing adaptive 1x/1.5x/2x charge­pump 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-fre­quency 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/PBATT

) 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 TADerating 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

1x/1.5x/2x White LED Charge Pump with

Two LDOs in 4mm x 4mm Thin QFN

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

19-3688; Rev 3; 6/08

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.

Pin Configuration appears at end of data sheet.

Typical Operating Circuit

*

EP = Exposed pad.

+

Denotes a lead-free package.

INPUT

2.7V TO 5.5V

10μF

MAIN ON/OFF

AND DIMMING

FLASH ON/OFF

DUAL-LDO ON/OFF

DUAL-LDO

VOLTAGE

SELECTION

C2P C2N

MAX8631X/Y

1μF

OUTPUT

UP TO 480mA

OUT

M1
M2
M3
M4

F1
F2
F3
F4

LDO1
LDO2

REFSETM SETF

0.01μF

10μF

MAIN FLASH

CAMERA
MODULE

1μF1μF

1μF

C1P C1N
PIN

IN

GND

PGND

ENM1

ENM2

ENF

ENLDO

P1

P2

PART TEMP RANGE PIN-PACKAGE

MAX8631XETI+ -40°C to +85°C

MAX8631YETI+ -40°C to +85°C

28 Thin QFN-EP*
4mm x 4mm (T2844-1)

28 Thin QFN-EP*
4mm x 4mm (T2844-1)

MAX8631X/Y

1x/1.5x/2x White LED Charge Pump with Two
LDOs in 4mm x 4mm Thin QFN

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN= 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 TA= +25°C.) (Note 1)

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.

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 (VIN+ 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

IN Operating Voltage 2.7 5.5 V

Undervoltage-Lockout Threshold VIN rising or falling 2.25 2.45 2.60 V

Undervoltage-Lockout Hysteresis 130 mV

Supply Current

Shutdown Supply Current ENM1 = ENM2 = ENF = ENLDO = GND

EN_ High Voltage VIN = 2.7V to 5.5V 1.4 V

EN_ Low Voltage V

EN_ Input Current V

ENM_ or ENF Low Shutdown
Delay t

SHDN

ENM_ or ENF t

ENM_ or ENF t

Initial ENM_ or ENF t

P1, P2 Shutdown Input Current 1µA

P1, P2 Input Impedance 150 kΩ

Thermal-Shutdown Threshold Temperature rising +160 °C

Thermal-Shutdown Hysteresis 20 °C

CHARGE PUMP

Overvoltage-Protection Threshold V

Soft-Start Time 2ms

PARAMETER CONDITIONS MIN TYP MAX UNITS

LO

HI

1MHz switching, no load, 1.5x or 2x mode 4.0 5.5

1x mode 10% setting, ENF = GND, V

= I

I

LDO1

ENM1 = ENM2 = ENF = GND, V
I

LDO1

See Figure 2 2.5 ms

See Figure 2 0.5 250.0 µs

See Figure 2 0.5 µs

HI

Only required for first ENM_ or ENF pulse, see Figure 2 200 µs

LDO2

= I

LDO2

= 2.7V to 5.5V 0.4 V

IN

= 0V or 5.5V

EN_

rising 5 V

OUT

= 0A

= 0A

ENLDO

= VIN,

ENLDO

= VIN,

TA = +25°C 0.01 5

T

= +85°C 0.1

A

TA = +25°C 0.01 1

= +85°C 0.1

T

A

0.4

110 µA

mA

µA

µA

MAX8631X/Y

ELECTRICAL CHARACTERISTICS (continued)

(VIN= 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 TA= +25°C.) (Note 1)

1x/1.5x/2x White LED Charge Pump with Two

LDOs in 4mm x 4mm Thin QFN

_______________________________________________________________________________________ 3

1x to 1.5x or 1.5x to 2x Mode
Transition Threshold

Input Voltage-Mode Transition
Hysteresis

Charge-Pump Maximum OUT
Current

Charge-Pump Short-Circuit
Current

Switching Frequency 1 MHz

OUT Pulldown Resistance in
Shutdown

LED DRIVER

SET_ Bias Voltage TA = +25°C 0.6 V

SET_ Leakage in Shutdown ENM_ = ENF = GND

SET_ Current Range 10 145 µA

SETM-to-Main LED Current Ratio

/I

(I

M_

SETM

SETF-to-Flash LED Current Ratio

F_/ISETF

)

(I

M_, F_ Current Accuracy

Maximum Main LED Sink Current R

Maximum Flash LED Sink Current R

Current-Derating-Function Start
Temperature

Current-Derating-Function Slope TA = +40°C to +85°C -1.7 %/°C

Dropout Voltage (Note 2) 40 90 mV

1.5x and 2x Regulation Voltage 150 mV

M_, F_ Leakage in Shutdown ENM_ = ENF = GND

LDO_

Output Voltage Accuracy

Output Current Range 0 200 mA

Current Limit V

Soft-Start Current Limit 160 mA

PARAMETER CONDITIONS MIN TYP MAX UNITS

)

V

≥ 3.15V, V

IN

1x mode, (VIN - V

1.5x mode, (1.5VIN - V

2x mode, (2V

V

< 1.25V 500 mA

OUT

ENM_ = ENF = GND 5 kΩ

100% setting, M1–M4 230 A/A

100% setting, F1–F4 690 A/A

TA = +25°C -1.25 +1.25

T

= -40°C to current derating start temperature -4 +4

A

SETM

= 4.12kΩ, IF1 + IF2 + IF3 + I

SETF

I

= 150mA, relative to V

LDO_

LDO_

OUT

IN

= 4.6kΩ, for each M_ 30 mA

= 0V 280 475 750 mA

= 3.9V 580 mA

) / I

OUT

OUT

) / I

OUT

OUT

- V

) / I

OUT

OUT

TA = +25°C 0.01 1

T

A

F4

TA = +25°C 0.01 1

= +85°C 0.1

T

A

OUT(NOM)

90 100 110 mV

150 mV

0.3 1.0

1.1 4.0Open-Loop OUT Resistance

1.5 4.14

= +85°C 0.1

400 mA

+40 °C

(Note 3) -1.7 0 +1.7 %

Ω

µA

%

µA

MAX8631X/Y

1x/1.5x/2x White LED Charge Pump with
Two LDOs in 4mm x 4mm Thin QFN

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VIN= 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 TA= +25°C.) (Note 1)

Note 1: All devices are 100% production tested at TA= +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)) ≤ VIN≤ 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 VIN=

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

(VIN= V

EN_

= 3.6V, circuit of Figure 1, TA= +25°C, unless otherwise noted.)

EFFICIENCY vs. Li+ BATTERY

VOLTAGE DRIVING FOUR MAIN LEDs

MAX8631X toc01

Li+ BATTERY VOLTAGE (V)

EFFICIENCY P

LED

/P

BATT

(%)

3.93.63.33.0

50

60

70

80

90

100

40

2.7 4.2

15mA/LED

4.5mA/LED

1.5mA/LED

EFFICIENCY vs. Li+ BATTERY

VOLTAGE DRIVING FLASH LED MODULE

MAX8631 toc02

Li+ BATTERY VOLTAGE (V)

EFFICIENCY P

LED

/P

BATT

(%)

3.93.63.33.0

50

60

70

80

90

100

40

2.7 4.2

80mA TOTAL

160mA TOTAL

400mA TOTAL

BATTERY CURRENT vs. SUPPLY VOLTAGE

DRIVING FOUR MAIN LEDs

MAX8631X toc03

SUPPLY VOLTAGE (V)

BATTERY CURRENT (mA)

3.93.63.33.0

20

40

60

80

100

120

0

2.7 4.2

I

LED

= 15mA

I

LED

= 4.5mA

I

LED

= 1.5mA

V

IN

FALLING

V

IN

RISING

Soft-Start Done Time 100 µs

Dropout Voltage I

Load Regulation VIN = 3.7V, 100µA < I

Power-Supply Rejection

/ΔV

ΔV

OUT

Output Noise Voltage (RMS) 10Hz to 100kHz, C

PARAMETER CONDITIONS MIN TYP MAX UNITS

= 200mA (Note 4) 120 320 mV

LDO_

< 200mA 1.3 %

LDO_

IN

10Hz to 10kHz, C

LDO_

LDO_

= 1µF, I

= 1µF, I

= 10µA -60 dB

LDO_

= 10mA 40 µV

LDO_

RMS

MAX8631X/Y

1x/1.5x/2x White LED Charge Pump with

Two LDOs in 4mm x 4mm Thin QFN

_______________________________________________________________________________________

5

Typical Operating Characteristics (continued)

(VIN= V

EN_

= 3.6V, circuit of Figure 1, TA= +25°C, unless otherwise noted.)

BATTERY CURRENT vs. SUPPLY

VOLTAGE DRIVING FLASH

900

800

700

I

= 400mA

FLASH

600

500

I

= 160mA

FLASH

400

300

BATTERY CURRENT (mA)

200

100

0

2.7 4.2

I

FLASH

SUPPLY VOLTAGE (V)

INPUT RIPPLE VOLTAGE vs. SUPPLY

VOLTAGE WITH FLASH AND MAIN LEDs

10

FOUR MAIN LEDs AT 15mA EACH

9

I

8

)

7

RMS

6

5

4

3

INPUT RIPPLE (mV

2

1

0

2.7 5.5

= 10mA

FLASH

I

FLASH

SUPPLY VOLTAGE (V)

= 80mA

= 40mA

I

FLASH

3.93.63.33.0

= 100mA

5.14.73.1 3.5 3.9 4.3

INPUT RIPPLE VOLTAGE vs. SUPPLY

VOLTAGE WITH FOUR MAIN LEDs

1.2

I

= 15mA

1.0

)

RMS

0.8

0.6

0.4

INPUT RIPPLE (mV

0.2

0

2.7 5.5

LED

I

= 4.5mA

LED

I

= 1.5mA

LED

SUPPLY VOLTAGE (V)

LED CURRENT MATCHING vs. SUPPLY

VOLTAGE WITH FOUR FLASH LEDs

102.0

101.5

101.0

100.5

100.0

99.5

99.0

FLASH LED CURRENT (mA)

98.5

98.0

2.7 5.5
SUPPLY VOLTAGE (V)

160

150

MAX8631X toc04

140

130

120

110

100

GROUND PIN SUPPLY CURRENT (μA)

90

80

16.0

15.8

15.6

MAX8631X toc07

15.4

15.2

15.0

14.8

14.6

MAIN LED CURRENT (mA)

14.4

14.2

14.0

LDO GROUND PIN SUPPLY

CURRENT vs. SUPPLY VOLTAGE

V

= V

= 0V, V

ENM

ENF

NO LOAD, BOTH LDOs

2.7 5.5
SUPPLY VOLTAGE (V)

= VIN

ENLDO

150mA, BOTH LDOs

5.14.73.9 4.33.53.1

LED CURRENT MATCHING vs. SUPPLY

VOLTAGE WITH FOUR MAIN LEDs

2.7 5.5

SUPPLY VOLTAGE (V)

5.14.73.9 4.33.53.1

MAX8631X toc05

MAX8631X toc08

MAX8631X toc06

5.14.74.33.93.53.1

MAX8631X toc09

5.14.74.33.93.53.1

LED CURRENT vs. AMBIENT

TEMPERATURE WITH FOUR MAIN LEDs

70

60

50

40

30

20

TOTAL LED CURRENT (mA)

10

0

-40 85
AMBIENT TEMPERATURE (°C)

LED CURRENT vs. AMBIENT
TEMPERATURE WITH FLASH

450

400

MAX8631X toc10

350

300

250

200

150

TOTAL LED CURRENT (mA)

100

50

0

603510-15

-40 85
AMBIENT TEMPERATURE (°C)

603510-15

MAX8631X toc11

MAIN LED CURRENT (mA)

INDIVIDUAL MAIN LED CURRENT

vs. R

100

10

1

R

SETM

SETM

10

(kΩ)

MAX8631X toc12

1001