Maxim > Products > Power and Battery Management > MAX1984, MAX1985, MAX1986

MAX1984, MAX1985, MAX1986

Ultra-Efficiency White LED Drivers

Ultra-Efficient, White LED Drivers Use Individual Regulators to Control the Current of Up to Eight LEDs

Overview

Technical Documents

Ordering Info

Status

Part Number	Status
MAX1984	Active: In Production.
MAX1984ETP	Active: In Production.
MAX1985	Active: In Production. See Ordering Information for details.
MAX1986	Active: In Production.

Description

The MAX1984/MAX1985/MAX1986 are white light-emitting 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 dimming 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 x 4mm thin QFN package.

Data Sheet

Download	Rev 0	(PDF, 344kB)
E-Mail

Key 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

Applications/Uses

Cell Phones
Digital Cameras
PDAs and Handheld PCs

Key Specifications:

White LED Drivers

Part Number

Topology

LEDs

Config.

Dimming Control

V_{CURR_SENSE}
(mV)

P_OUT
(W)

I_LED
(mA)

V_IN
(V)

I_CC
(mA)

V_OUT
(V)

Oper. Freq.
(kHz)

Package/Pins

Budgetary Price

max num. of

max

min

max

See Notes

MAX1984

Inductor Based

Parallel

Analog

Digital

PWM

100

0.8

2.7

5.5

0.6

1000

TQFN/20

$2.33 @1k

MAX1985

0.6

TQFN/20

$2.33 @1k

MAX1986

0.4

TQFN/16

$2.98 @1k

See All White LED Drivers (47)

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Diagram

Pin Configuration

Application Notes

Tutorial 4689		Blood Pressure Monitor Design Considerations
Tutorial 4690		Important Design Considerations for Digital Thermometers
Tutorial 4694		Introduction to Digital Stethoscopes and Electrical Component Selection Criteria

Reliability Reports

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Software/Models

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Ordering Information

Filters:

Part Number:

Package:

Temperature:

Tape and Reel

Sample

Part Number	Free Sample	Buy	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX1984ETP			Active		TQFN;20 pin;16.8 mm² Outline Drawing:21-0139 (PDF) Land Pattern: 90-0037 (PDF) Use pkgcode/variation: T2044-3*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1984ETP+			Active		TQFN;20 pin;16.8 mm² Outline Drawing:21-0139 (PDF) Land Pattern: 90-0037 (PDF) Use pkgcode/variation: T2044+3*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX1984ETP+T			Active		TQFN;20 pin;16.8 mm² Outline Drawing:21-0139 (PDF) Land Pattern: 90-0037 (PDF) Use pkgcode/variation: T2044+3*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX1984ETP-T			Active		QFN;20 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX1985ETP			Active		TQFN;20 pin;16.8 mm² Outline Drawing:21-0139 (PDF) Land Pattern: 90-0037 (PDF) Use pkgcode/variation: T2044-3*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1985ETP+			Active		TQFN;20 pin;16.8 mm² Outline Drawing:21-0139 (PDF) Land Pattern: 90-0037 (PDF) Use pkgcode/variation: T2044+3*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX1985ETP+T			Active		QFN; Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX1985ETP-T			Active		QFN;20 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX1985EVKIT		N/A	No Longer Available	MAX8790EVKIT	KIT; Land Pattern: Not Available		See data sheet
MAX1986ETE			Active		TQFN;16 pin;16.8 mm² Outline Drawing:21-0139 (PDF) Land Pattern: 90-0070 (PDF) Use pkgcode/variation: T1644-4*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
Part Number	Free Sample	Buy	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX1986ETE+			Active		TQFN;16 pin;16.8 mm² Outline Drawing:21-0139 (PDF) Land Pattern: 90-0070 (PDF) Use pkgcode/variation: T1644+4*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX1986ETE+T			Active		QFN; Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX1986ETE-T			Active		QFN;16 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet

Notes:

Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt; -D = drypack; -U/+U on DS parts = cut tape. More: See Full Data Sheet or Maxim Product Naming Conventions.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

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[ 2003-03-03 ]

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Information Index

Overview		Technical Documents		Ordering Info		Related Products
Description Key Features Applications/Uses Key Specifications Diagram Notes and Comments		Data Sheet Application Notes Evaluation Kits Product Guides Reliability Reports Software/Models		Price and Availability Samples Buy Online Package Information Lead-Free Information		Similar Products by Function Similar Products by Application Evaluation Kits Products with Similar Part Numbers Products Used With This

Document Ref.: 19-2761 Rev 0; 2003-02-23
This page last modified: 2009-10-13