Rainbow Electronics MAX8645Y User Manual

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

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.

Pin Configuration appears at end of data sheet.

Typical Operating Circuit

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

PINPACKAGE

28 TQFN-EP 4mm x 4mm

INPUT

2.7V TO 5.5V

10μF

MAIN ON/OFF

AND DIMMING

FLASH ON/OFF

DUAL-LDO ON/OFF

DUAL-LDO

VOLTAGE

SELECTION

MAX8645X MAX8645Y

1μF

C2P C2N

REFSETM SETF

OUT

LDO1 LDO2

M1 M2 M3 M4 M5 M6

F1 F2

0.01μF

OUTPUT

UP TO 580mA

10μF

MAIN

FLASH

CAMERA MODULE

1μF1μF

1μF

C1P C1N PIN

GND

PGND

ENM1

ENM2

ENF

ENLDO

PART TEMP RANGE

MAX8645XETI+ -40°C to +85°C

MAX8645YETI+ -40°C to +85°C

PKG

CODE

T2844-1

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,

= -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

+ 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

+ 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

= +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

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

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

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

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

= I

LDO1

ENM1 = ENM2 = ENF = GND, V I

LDO1

See Figure 1 1.5 2.0 2.5 ms

See Figure 1 0.5 250.0 µs

See Figure 1 0.5 µs

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

LDO2

= I

LDO2

= 2.7V to 5.5V 0.4 V

= 0V or 5.5V

EN_

rising 5 V

OUT

= 0A

ENLDO

= VIN,

ENLDO

= VIN,

TA = +25°C 0.01 5

= +85°C 0.1

TA = +25°C 0.01 1

= +85°C 0.1

0.4

110 µA

µA

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,

= -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

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

SETM

SETF-to-Flash LED Current Ratio

F_/ISETF

)

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

)

≥ 3.15V, V

1x mode (VIN - V

1.5x mode (1.5VIN - V

2x mode (2V

< 1.25V 500 mA

OUT

ENM_ = ENF = GND 5 kΩ

100% setting, M1–M6 230 A/A

100% setting, F1 and F2 1380 A/A

TA = +25°C -1.25 +1.25

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

SETM

= 4.12kΩ, IF1 + I

SETF

= 150mA, relative to V

LDO_

OUT

- V

= 4.6kΩ, for each M_ 30 mA

= 0V 280 475 750 mA

= 3.9V 580 mA

) / I

OUT

) / I

OUT

) / I

OUT

TA = +25°C 0.01 1

TA = +25°C 0.01 2

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

= +85°C 0.1

(Note 3) -1.7 0 +1.7 %

µA

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,

= -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

- V

OUT

when V

OUT

is 100mV below the value of V

OUT

measured when VIN=

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

BATT

(%)

3.93.63.33.0

100

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

BATT

(%)

3.93.63.33.0

100

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

120

150

180

2.7 4.2

LED

= 15mA

LED

= 4.5mA

LED

= 1.5mA

FALLING

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_

10Hz to 10kHz, C

= 1µF, I

LDO_

= 10µA -60 dB

LDO_

= 1µF, I

= 10mA 40 µV

LDO_

RMS

MAX8645X/MAX8645Y

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

Two LDOs in 4mm x 4mm TQFN

_______________________________________________________________________________________ 5

Typical Operating Characteristics (continued)

(VIN= V

EN_

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

900

800

700

600

500

FLASH

400

300

BATTERY CURRENT (mA)

200

100

2.7 4.2

INPUT RIPPLE VOLTAGE vs. SUPPLY

VOLTAGE WITH FLASH AND MAIN LEDs

FOUR MAIN LEDs AT 15mA EACH

)

RMS

INPUT RIPPLE (mV

2.7 5.5

BATTERY CURRENT vs. SUPPLY

VOLTAGE DRIVING FLASH

= 400mA

FLASH

= 160mA

= 80mA

FLASH

3.93.63.33.0

SUPPLY VOLTAGE (V)

= 40mA

FLASH

= 160mA

FLASH

= 400mA

FLASH

SUPPLY VOLTAGE (V)

160

150

MAX8645Y toc04

140

130

120

110

100

GROUND-PIN SUPPLY CURRENT (μA)

16.0

15.8

15.6

MAX8645Y toc07

15.4

15.2

15.0

14.8

14.6

MAIN LED CURRENT (mA)

14.4

14.2

5.14.73.1 3.5 3.9 4.3

14.0

LDO GROUND-PIN SUPPLY

CURRENT vs. SUPPLY VOLTAGE

= V

ENM_

NO LOAD, BOTH LDOs

2.7 5.5

= 0V, V

ENF

ENLDO

SUPPLY VOLTAGE (V)

LED CURRENT MATCHING vs. SUPPLY

VOLTAGE WITH SIX MAIN LEDs

2.7 5.5 SUPPLY VOLTAGE (V)

= VIN

150mA, BOTH LDOs

5.14.73.9 4.33.53.1

1.8

1.5

MAX8645Y toc05

)

RMS

1.2

0.9

0.6

INPUT RIPPLE (mV

0.3

2.7 5.5

LED CURRENT MATCHING vs. SUPPLY

102.0

101.5

MAX8645Y toc08

101.0

100.5

100.0

99.5

99.0

FLASH LED CURRENT (mA)

98.5

98.0

2.7 5.5

INPUT RIPPLE VOLTAGE vs. SUPPLY

VOLTAGE WITH SIX MAIN LEDs

= 15mA

LED

= 4.5mA

LED

= 1.5mA

LED

5.14.74.33.93.53.1

SUPPLY VOLTAGE (V)

VOLTAGE WITH TWO FLASH LEDs

5.14.74.33.93.53.1

SUPPLY VOLTAGE (V)

MAX8645Y toc06

MAX8645Y toc09

LED CURRENT vs. AMBIENT

TEMPERATURE WITH SIX MAIN LEDs

105

TOTAL LED CURRENT (mA)

-40 85 TA (°C)

LED CURRENT vs. AMBIENT TEMPERATURE WITH FLASH

450

400

MAX8645Y toc10

350

300

250

200

150

TOTAL LED CURRENT (mA)

100

603510-15

-40 85 TA (°C)

603510-15

MAX8645Y toc11

MAIN LED CURRENT (mA)

INDIVIDUAL MAIN LED CURRENT

vs. R

100

SETM

(kΩ)

MAX8645Y toc12

1001

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