General Description

The MAX16822A/MAX16822B step-down constant-cur-

rent high-brightness LED (HB LED) drivers provide a

cost-effective design solution for automotive

interior/exterior lighting, architectural and ambient light-

ing, LED bulbs, and other LED illumination applications.

The MAX16822A/MAX16822B operate from a +6.5V to

+65V input-voltage range and can provide an output

current up to 350mA, if operated up to a temperature of

+125°C, or up to 500mA, if operated up to a tempera-

ture of +105°C. A high-side current-sense resistor

adjusts the output current and a dedicated pulse-width

modulation (PWM) input enables pulsed LED dimming

over a wide range of brightness levels.

These devices are well suited for applications requiring

a wide input-voltage range. The high-side current sens-

ing and an integrated current-setting circuitry minimize

the number of external components while delivering an

average output current with ±3% accuracy. A hysteretic

control method ensures excellent input supply rejection

and fast response during load transients and PWM dim-

ming. The MAX16822A allows 10% current ripple and

the MAX16822B allows 30% current ripple. Both

devices operate up to a switching frequency of 2MHz,

thus allowing the use of small-sized components.

The MAX16822A/MAX16822B offer an analog dimming

feature that reduces the output current by applying an

external DC voltage below the internal 2V threshold volt-

age from TEMP_I to GND. TEMP_I also sources 25µA to

a negative temperature coefficient (NTC) thermistor con-

nected between TEMP_I and GND, thus providing an

analog thermal-foldback feature that reduces the LED

current when the temperature of the LED string exceeds

a specified temperature point.

An additional feature includes thermal-shutdown pro-

tection that turns off the LX driver when the junction

temperature exceeds +165°C.

The MAX16822A/MAX16822B operate over the -40°C to

+125°C automotive temperature range and are available

in an 8-pin SO package.

Applications

Architectural, Industrial, and Ambient Lighting

Automotive RCL, DRL, and Fog Lights

Heads-Up Displays

Indicator and Emergency Lighting

Features

♦ High-Efficiency Solution

♦ 6.5V to 65V Input-Voltage Range

♦ Output Current Up to 500mA

♦ On-Board 65V, 0.85Ω Power MOSFET

♦ Hysteretic Control: Up to 2MHz Switching

Frequency

♦ ±3% LED Current Accuracy

♦ 200mV Current-Sense Reference

♦ Resistor-Programmable Constant LED Current

♦ Integrated High-Side Current Sense

♦ Thermal-Foldback Protection/Linear Dimming

♦ Thermal-Shutdown Protection

♦ Available in an 8-Pin SO Package

♦ -40°C to +125°C Operating Temperature Range

2MHz, High-Brightness LED Drivers with

Integrated MOSFET and High-Side Current Sense

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

LX

LX

PGND

1

2

8

7

TEMP_I

DIM

IN

GND

CS

3

4

6

5

MAX16822A

MAX16822B

L1

C2

ON

OFF

D1

HB LEDs

NTC*

*OPTIONAL

C1

Typical Application Circuit

19-4141; Rev 2; 5/09

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

EVALUATION

KIT

AVAILABLE

+

Denotes a lead(Pb)-free/RoHS-compliant package.

PART

TEMP RANGE

PIN-PACKAGE

MAX16822AASA+

-40°C to +125°C

8 SO

MAX16822BASA+

-40°C to +125°C

8 SO

Pin Configuration appears at end of data sheet.