Maxim MAX8645YETI+, MAX8645X Datasheet

EVALUATION KIT

AVAILABLE

General Description

The MAX8645X/MAX8645Y charge pumps drive up to
eight white LEDs with regulated constant current for uni­form 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 pro­grammable to meet different camera-module require­ments. The MAX8645X and MAX8645Y differ only in LDO
output voltages. By utilizing adaptive 1x/1.5x/2x charge­pump 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 compo­nents, 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/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 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

MAX8645X/MAX8645Y

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

Two LDOs in 4mm x 4mm TQFN

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-3978; Rev 3; 12/06

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.

PART TEMP RANGE

PIN­PACKAGE

PKG

CODE

MAX8645XETI+ -40°C to +85°C

28 TQFN-EP
4mm x 4mm

T2844-1

MAX8645YETI+ -40°C to +85°C

28 TQFN-EP
4mm x 4mm

T2844-1

Pin Configuration appears at end of data sheet.

MAIN ON/OFF

AND DIMMING

MAX8645X
MAX8645Y

1μF

10μF

0.01μF

10μF

PIN

IN

PGND

GND

P1

P2

OUT

MAIN

FLASH

OUTPUT

UP TO 580mA

1μF1μF

LDO1
LDO2

C2P C2N

1μF

C1P C1N

REFSETM SETF

CAMERA
MODULE

DUAL-LDO

VOLTAGE

SELECTION

INPUT

2.7V TO 5.5V

ENM2

ENM1

ENF

ENLDO

M1
M2
M3
M4
M5
M6

F1
F2

FLASH ON/OFF

DUAL-LDO ON/OFF

Typical Operating Circuit

EP = Exposed paddle.
+Denotes a lead-free package.

MAX8645X/MAX8645Y

1x/1.5x/2x White LED Charge Pumps with Two
LDOs in 4mm x 4mm TQFN

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, M5, M6, F1,

F2 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 the 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 TQFN 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

PARAMETER CONDITIONS MIN TYP MAX UNITS

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

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

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

ENLDO

= VIN,

I

LDO1

= I

LDO2

= 0A

0.4

mA

Supply Current

ENM1 = ENM2 = ENF = GND, V

ENLDO

= VIN,

I

LDO1

= I

LDO2

= 0A

110 µA

TA = +25°C 0.01 5

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

T

A

= +85°C 0.1

µA

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

EN_ Low Voltage V

IN

= 2.7V to 5.5V 0.4 V

TA = +25°C 0.01 1

EN_ Input Current V

EN_

= 0V or 5.5V

T

A

= +85°C 0.1

µA

ENM_ or ENF Low Shutdown
Delay t

SHDN

See Figure 1 1.5 2.0 2.5 ms

ENM_ or ENF t

LO

See Figure 1 0.5 250.0 µs

ENM_ or ENF t

HI

See Figure 1 0.5 µs

Initial ENM_ or ENF t

HI

Only required for first ENM_ or ENF pulse; see Figure 1 200 µs

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

OUT

rising 5 V

Soft-Start Time 2ms

MAX8645X/MAX8645Y

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

LDOs in 4mm x 4mm TQFN

_______________________________________________________________________________________ 3

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)

PARAMETER CONDITIONS MIN TYP MAX UNITS

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

90 100 110 mV

Input Voltage-Mode Transition
Hysteresis

150 mV

Charge-Pump Maximum OUT
Current

V

IN

≥ 3.15V, V

OUT

= 3.9V 580 mA

1x mode (VIN - V

OUT

) / I

OUT

0.3 1.0

1.5x mode (1.5VIN - V

OUT

) / I

OUT

1.1 4.0Open-Loop OUT Resistance

2x mode (2V

IN

- V

OUT

) / I

OUT

1.5 4.14

Ω

Charge-Pump Short-Circuit
Current

V

OUT

< 1.25V 500 mA

Switching Frequency 1 MHz

OUT Pulldown Resistance in
Shutdown

ENM_ = ENF = GND 5 kΩ

LED DRIVER

SET_ Bias Voltage TA = +25°C 0.6 V

TA = +25°C 0.01 1

SET_ Leakage in Shutdown ENM_ = ENF = GND

T

A

= +85°C 0.1

µA

SET_ Current Range 10 145 µA

SETM-to-Main LED Current Ratio
(I

M_

/I

SETM

)

100% setting, M1–M6 230 A/A

SETF-to-Flash LED Current Ratio
(I

F_/ISETF

)

100% setting, F1 and F2 1380 A/A

TA = +25°C -1.25 +1.25

M_, F_ Current Accuracy

T

A

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

%

Maximum Main LED Sink Current R

SETM

= 4.6kΩ, for each M_ 30 mA

Maximum Flash LED Sink Current R

SETF

= 4.12kΩ, IF1 + I

F2

400 mA

Current-Derating-Function Start
Temperature

+40 °C

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

TA = +25°C 0.01 2

M_, F_ Leakage in Shutdown ENM_ = ENF = GND

T

A

= +85°C 0.1

µA

LDO_

Output Voltage Accuracy

I

LDO_

= 150mA, relative to V

OUT(NOM)

(Note 3) -1.7 0 +1.7 %

Output Current Range 0 200 mA

Current Limit V

LDO_

= 0V 280 475 750 mA

Soft-Start Current Limit 160 mA

MAX8645X/MAX8645Y

1x/1.5x/2x White LED Charge Pumps with
Two LDOs in 4mm x 4mm TQFN

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)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Soft-Start Done Time 100 µs

Dropout Voltage I

LDO_

= 200mA (Note 4) 120 320 mV

Load Regulation VIN = 3.7V, 100µA < I

LDO_

< 200mA 1.3 %

Power-Supply Rejection
ΔV

OUT

/ΔV

IN

10Hz to 10kHz, C

LDO_

= 1µF, I

LDO_

= 10µA -60 dB

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

LDO_

= 1µF, I

LDO_

= 10mA 40 µV

RMS

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 2, TA= +25°C, unless otherwise noted.)

EFFICIENCY vs. Li+ BATTERY

VOLTAGE DRIVING SIX MAIN LEDs

MAX8645Y 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

MAX8645Y 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 SIX MAIN LEDs

MAX8645Y toc03

SUPPLY VOLTAGE (V)

BATTERY CURRENT (mA)

3.93.63.33.0

30

60

90

120

150

180

0

2.7 4.2

I

LED

= 15mA

I

LED

= 4.5mA

I

LED

= 1.5mA

V

IN

FALLING

V

IN

RISING

MAX8645X/MAX8645Y

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

Two LDOs in 4mm x 4mm TQFN

_______________________________________________________________________________________ 5

BATTERY CURRENT vs. SUPPLY

VOLTAGE DRIVING FLASH

MAX8645Y toc04

SUPPLY VOLTAGE (V)

BATTERY CURRENT (mA)

3.93.63.33.0

100

200

300

400

500

600

700

800

900

0

2.7 4.2

I

FLASH

= 400mA

I

FLASH

= 160mA

I

FLASH

= 80mA

LDO GROUND-PIN SUPPLY

CURRENT vs. SUPPLY VOLTAGE

MAX8645Y toc05

SUPPLY VOLTAGE (V)

GROUND-PIN SUPPLY CURRENT (μA)

5.14.73.9 4.33.53.1

90

100

110

120

130

140

150

160

80

2.7 5.5

V

ENM_

= V

ENF

= 0V, V

ENLDO

= VIN

150mA, BOTH LDOs

NO LOAD, BOTH LDOs

INPUT RIPPLE VOLTAGE vs. SUPPLY

VOLTAGE WITH SIX MAIN LEDs

MAX8645Y toc06

SUPPLY VOLTAGE (V)

INPUT RIPPLE (mV

RMS

)

5.14.74.33.93.53.1

0.3

0.6

0.9

1.2

1.5

1.8

0

2.7 5.5

I

LED

= 15mA

I

LED

= 4.5mA

I

LED

= 1.5mA

INPUT RIPPLE VOLTAGE vs. SUPPLY

VOLTAGE WITH FLASH AND MAIN LEDs

MAX8645Y toc07

SUPPLY VOLTAGE (V)

INPUT RIPPLE (mV

RMS

)

5.14.73.1 3.5 3.9 4.3

1

2

3

4

5

7

9

6

8

10

0

2.7 5.5

FOUR MAIN LEDs AT 15mA EACH

I

FLASH

= 40mA

I

FLASH

= 160mA

I

FLASH

= 400mA

LED CURRENT MATCHING vs. SUPPLY

VOLTAGE WITH SIX MAIN LEDs

MAX8645Y toc08

SUPPLY VOLTAGE (V)

MAIN LED CURRENT (mA)

5.14.73.9 4.33.53.1

14.2

14.4

14.6

14.8

15.0

15.2

15.4

15.6

15.8

16.0

14.0

2.7 5.5

LED CURRENT MATCHING vs. SUPPLY

VOLTAGE WITH TWO FLASH LEDs

MAX8645Y toc09

SUPPLY VOLTAGE (V)

FLASH LED CURRENT (mA)

5.14.74.33.93.53.1

99.0

98.5

99.5

100.0

100.5

101.0

101.5

102.0

98.0

2.7 5.5

LED CURRENT vs. AMBIENT

TEMPERATURE WITH SIX MAIN LEDs

MAX8645Y toc10

TA (°C)

TOTAL LED CURRENT (mA)

603510-15

15

30

45

60

75

90

105

0

-40 85

LED CURRENT vs. AMBIENT

TEMPERATURE WITH FLASH

MAX8645Y toc11

TA (°C)

TOTAL LED CURRENT (mA)

603510-15

50

100

150

200

250

300

350

400

450

0

-40 85

INDIVIDUAL MAIN LED CURRENT

vs. R

SETM

MAX8645Y toc12

R

SETM

(kΩ)

MAIN LED CURRENT (mA)

10

10

100

1

1001

Typical Operating Characteristics (continued)

(VIN= V

EN_

= 3.6V, circuit of Figure 2, TA= +25°C, unless otherwise noted.)