MAX1986ETE+ Datasheet MAX1985ETP+T, MAX1984ETP+, MAX1985ETP+ | P1-P3

General Description

The MAX1984/MAX1985/MAX1986 are white light-emit-

ting diode (LED) drivers that use individual regulators to

control the current of up to eight LEDs. A high-efficiency

step-up regulator generates just enough voltage to keep

all the current regulators in regulation. A versatile dim-

ming interface accommodates analog, digitally adjusted

pulse-width modulation (DPWM), or parallel control.

The individual current regulators allow good current

matching between LEDs. Open or shorted LEDs cannot

affect the performance of other LEDs.

The step-up regulator achieves high efficiency by using

synchronous rectification. The internal N-channel switch

and P-channel synchronous rectifier eliminate the need

for external MOSFETs and diodes. The 1MHz switching

frequency allows the use of low-profile inductors and

ceramic capacitors.

The brightness can be easily adjusted using a multi-

mode dimming interface, which allows brightness control

through a DPWM signal, a 2- or 3-bit parallel control

interface, or an analog signal. The DPWM signal can be

connected directly to the control pin without the need for

an external RC filter if its frequency is 10kHz or above.

The MAX1984 drives up to eight LEDs, the MAX1985

drives up to six LEDs, and the MAX1986 drives up to

four LEDs. Each device has an LED select pin (SEL)

that allows one subset, the other subset, or all LEDs to

be illuminated. All three devices are available in a

4mm ✕ 4mm thin QFN package.

Applications

PDAs and Hand-Held PCs

Cellular Phones

Digital Cameras

Features

♦ Synchronous Step-Up Regulator

Achieves >95% Efficiency

Internal Switch and Synchronous Rectifier

Eliminates External MOSFETs and Diodes

1MHz Fixed Frequency Minimizes Component

Sizes

♦ Up to 90% Total LED Efficiency

♦ Accurate LED Current Matching (8% max)

♦ Adjustable Maximum LED Current

♦ Multimode Dimming Control

Digital Pulse-Width Modulation Control

2-Bit Parallel Control

3-Bit Parallel Control

Analog Control

♦ Selectively Enable LEDs

♦ Open-LED Detection

♦ Unique 0.5mA LED Test Mode

♦ 2.7V to 5.5V Input Supply Range

♦ Small 4mm x 4mm 20-Pin Thin QFN Package

MAX1984/MAX1985/MAX1986

Ultra-High-Efficiency White

LED Drivers

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-2761; Rev 0; 1/03

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.

EVALUATION KIT

AVAILABLE

PART TEMP RANGE PIN-PACKAGE

NO. OF

LEDs

MAX1984ETP -40°C to +85°C 20 Thin QFN 8

MAX1985ETP -40°C to +85°C 20 Thin QFN 6

MAX1986ETE -40°C to +85°C 16 Thin QFN 4

20 19 18 17 16

6 7 8 9 10

MODE

BITC

BITA

LD3

LD4

LD5

LD6

BITB

REF

SETI

LD8

LD7

OUT

GND

LD1

LD2

TOP VIEW

4mm x 4mm

THIN QFN

LDG

SEL

MAX1984

20 19 18 17 16

6 7 8 9 10

MODE

BITC

BITA

LD2

LD3

LD4

LD5

BITB

REF

SETI

N.C.

LD6

OUT

GND

N.C.

LD1

4mm x 4mm

THIN QFN

LDG

SEL

MAX1985

16 15 14 13

5 6 7 8

MODE

BITC

LD2

LDG

LD4

BITA

BITB

REF

SETI

OUT

GND

LD1

4mm x 4mm

THIN QFN

LD3

SEL

MAX1986

Pin Configurations

MAX1984/MAX1985/MAX1986

Ultra-High-Efficiency White

LED Drivers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1; V

= 3.3V, SETI = BITA = BITB = BITC = SEL = IN, MODE = GND, C

OUT

= 4.7µF, C

REF

= 0.22µF, T

= 0°C to +85°C,

unless otherwise noted. Typical values are at T

= +25°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.

OUT, IN, BITA, BITB, BITC, LD1, LD2, LD3, LD4,

LD5, LD6, LD7, LD8 to GND ................................-0.3V to +6V

LDG to GND........................................................................±0.3V

LX to GND ................................................-0.3V to (V

OUT

+ 0.3V)

SETI, REF, MODE, SEL to GND...................-0.3V to (V

+ 0.3V)

Continuous Power Dissipation (T

= +70°C)

16-Pin Thin QFN (derate 16.9mW/°C above +70°C) ...1349mW

20-Pin Thin QFN (derate 16.9mW/°C above +70°C) ...1349mW

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 Supply Range 2.7 5.5 V

IN Undervoltage Lockout Threshold 50mV typical hysteresis 2.2 2.4 2.6 V

IN Quiescent Current BITA = BITB = BITC = IN, LD1 to LD8 = GND 400 600 µA

IN Shutdown Current BITA = BITB = BITC = GND 0.1 1 µA

REF Output Voltage I

REF

= 0 1.230 1.250 1.270 V

REF Line Regulation 2.7V < V

< 5.5V 0.2 5 mV

REF Load Regulation -1µA < I

REF

< +50µA 5 15 mV

Oscillator Frequency 0.8 1 1.2 MHz

Oscillator Maximum Duty Cycle 85 %

OUT Overvoltage Protection (OVP)

Threshold

LD1

to V

LD8

= 50mV, OUT rising, 100mV typical

hysteresis

5.1 5.3 5.5 V

INTERNAL MOSFET SWITCHES

N-Channel MOSFET On-Resistance I

= 200mA 0.4 0.8 Ω

N-Channel MOSFET Leakage Current V

= 5.5V, BITA = BITB = BITC = GND 0.1 1 µA

P-Channel MOSFET On-Resistance I

= 200mA 0.5 1 Ω

P-Channel MOSFET Leakage Current LX = GND, V

OUT

= 5.5V, BITA = BITB = BITC = GND 0.1 1 µA

MAX1984 0.50 0.65 0.81

MAX1985 0.40 0.52 0.65

N-Channel MOSFET Current Limit

MAX1986 0.30 0.39 0.52

CONTROL INPUTS

BITA, BITB, BITC Input Logic Low

Level

2.7V < V

< 5.5V 0.4 V

BITA, BITB, BITC Input Logic High

Level

2.7V < V

< 5.5V 1.6 V

MODE Input Logic Low Level 2.7V < V

< 5.5V 0.4 V

MODE Input Logic High Level 2.7V < V

< 5.5V V

- 0.4 V

MODE, BITA, BITB, BITC Input Bias

Current

2.7V < V

< 5.5V 0.01 1 µA

MAX1984/MAX1985/MAX1986

Ultra-High-Efficiency White

LED Drivers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1; V

= 3.3V, SETI = BITA = BITB = BITC = SEL = IN, MODE = GND, C

OUT

= 4.7µF, C

REF

= 0.22µF, T

= 0°C to +85°C,

unless otherwise noted. Typical values are at T

= +25°C.)

PARAMETER CONDITIONS MIN TYP MAX UNITS

SEL Input Logic Low Level 2.7V < V

< 5.5V 0.4 V

SEL Input Logic Midlevel 2.7V < V

< 5.5V 0.50 1.85 V

SEL Input Logic High Level 2.7V < V

< 5.5V 2.05 V

SEL = GND, current out of the pin 5

SEL Input Bias Current

SEL = IN, current into the pin 10

µA

FULL-SCALE LED CURRENT ADJUSTMENT

LD_

= 80mV, SETI = BITA = BITB = BITC = IN 16.5 18 19.5

_ = 80mV, R

SETI

= 278kΩ ±0.1%, BITA = BITB =

BITC = IN

22.5 25 27.5

_ = 80mV, R

SETI

= 1.8MΩ ±0.1%, BITA = BITB =

BITC = IN

12.5 14 15.5

LD_

= 80mV, R

SETI

= 597kΩ ±0.1%, BITA = BITB =

BITC = IN

16.5 18 19.5

L D 1

= 1V , R

S E T I

= 10kΩ , BITA = BITB = BITC = IN 26

LD1 to LD8 Output Current

SETI = GND 0.42 0.50 0.60

LD1 to LD8 Regulation Voltage

SETI = IN, I

= 120mA (MAX1984),

110mA (MAX1985), 98mA (MAX1986)

80 100 120 mV

SETI High-Level Threshold

(18mA LED Default Current)

2.7V < V

< 5.5V V

- 0.4 V

SETI Low-Level Threshold

(0.5mA LED Default Current)

2.7V < V

< 5.5V 50 125 mV

SETI Output Current SETI = GND 40 70 100 µA

OUTPUT CURRENT SOURCE

LD1 to LD8 On-Resistance V

LD_

= 50mV, V

OUT

= 3.5V 3 4 Ω

LD1 to LD8 Current-Source

Compliance

BITA = BITB = BITC = IN, 80mV < V

LD_

< 1V

(Note 1)

0.3 5 %

LD1 to LD8 Leakage Current BITA = BITB = BITC = GND 0.01 1 µA

DIGITAL BRIGHTNESS CONTROL

2-Bit Control DAC LSB

MODE = SETI = BITB = IN, BITA = BITC = GND

(Note 2)

26 33 39 %

3-Bit Control DAC LSB

SETI = BITC = IN, MODE = BITA = BITB = GND

(Note 2)

7 14 21 %

DPWM BRIGHTNESS CONTROL

DPWM Input Supply Range MODE = BITC = IN 2.3 5.5 V

DPWM Shutdown Duty Cycle BITC = GND 3 5 7 %

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P17

MAX1986ETE+

Mfr. #:

Buy MAX1986ETE+

Manufacturer:

Maxim Integrated

Description:

LED Lighting Drivers High-Efficiency White LED Drive

Lifecycle:

New from this manufacturer.

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MAX1986ETE+

MAX1986ETE+

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