Rainbow Electronics MAX16825 User Manual

General Description

The MAX16824/MAX16825 three-channel LED drivers
operate over a 6.5V to 28V input voltage range. These
devices provide three open-drain constant-current-sink­ing outputs that are rated to 36V and deliver up to
150mA of current to each string of high-brightness LEDs
(HB LEDs). The current at each output is programmable
by means of an external current-sense resistor. The
MAX16824 features three PWM inputs that control the
duty cycle of the output current, allowing a wide LED
dimming range to be implemented. The PWM inputs
also function as on/off control for each corresponding
output. The MAX16825 offers a 4-wire serial interface, a
3-bit shift register, and a 3-bit transparent latch. The ser­ial interface allows a microcontroller to configure the out­put channels using four inputs (DIN, CLK, LE, OE) and a
data output (DOUT). DOUT allows multiple drivers to be
cascaded and operated together.

The MAX16824/MAX16825’s on-board pass elements
minimize the need for external components, while at the
same time, providing ±5% LED current accuracy.
Additional features include a +5V (±5%) regulated output
with 4mA output current capability and thermal protection.

The MAX16824/MAX16825 are available in a thermally
enhanced 16-pin TSSOP-EP package and specified over
the -40°C to +125°C temperature range.

Applications

Industrial Lighting

Architectural and Decorative Lighting

Mood Lighting

Indoor and Outdoor LED Video Displays

Automotive Lighting

LCD Display Backlighting

Features

o 6.5V to 28V Operating Range

o Outputs Connected to 36V Supply for Long LED

Strings

o Three 36V-Rated Output Channels with

Independently Adjustable LED Current

o 150mA Output Current Per Channel

o ±5% LED Current Accuracy

o PWM Dimming

Three Independent Dimming Control Inputs
(MAX16824)
4-Wire Serial Interface LED Current Chopping
(MAX16825)

o +5V (±5%) Regulated Output with 4mA Source

Capability

o Fast Transient Dimming Response

o 200mV Current-Sense Reference Reduces Power

Loss

o Thermal Shutdown

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

o Thermally Enhanced, 16-Pin TSSOP Exposed

Paddle Package

MAX16824/MAX16825

High-Voltage, Three-Channel Linear

High-Brightness LED Drivers

________________________________________________________________

Maxim Integrated Products

1

19-1107; Rev 1; 1/08

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.

OUT1

OUT3

OUT2

CS1

CS2

CS3

IN

1

16

3

7

8

9

4

11

12

2

15

13

PWM1

PWM2

PWM3

REG

GND

C

REG

C

IN

V

IN

UP TO 36V

R

CS2

R

CS1

R

CS3

MAX16824

Typical Operating Circuits

Ordering Information

+

Denotes a lead-free package.

*

EP = Exposed paddle.

Pin Configurations appear at end of data sheet.

PART TEMP RANGE

PIN
PACKAGE

MAX16824AUE+ -40°C to +125°C 16 TSSOP-EP* U16E-3

MAX16825AUE+ -40°C to +125°C 16 TSSOP-EP* U16E-3

PKG

CODE

V

IN

C

IN

3

IN

MAX16825

6

CLK

7

DIN

MICROCONTROLLER

8

LE

9

OE

4

C

REG

REG

11

GND

1

OUT1

16

OUT2

12

OUT3

2

CS1

15

CS2

13

CS3

UP TO 36V

R

CS1

R

CS2

R

CS3

MAX16824/MAX16825

High-Voltage, Three-Channel Linear
High-Brightness LED Drivers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

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.

IN to GND ...............................................................-0.3V to +30V

OUT1, OUT2, OUT3 to GND ..................................-0.3V to +40V

CS1, CS2, CS3, REG to GND...................................-0.3V to +6V

PWM1, PWM2, PWM3 to GND .................................-0.3V to +6V

DIN, CLK, LE, OE, DOUT to GND ............................-0.3V to +6V

Maximum Current into Any Pin

(except OUT1, OUT2, OUT3) ........................................±20mA

Maximum Current into OUT1, OUT2, OUT3......................160mA

Continuous Power Dissipation (T

A

= +70°C)

16-Pin TSSOP-EP (derate 18.9mW/°C above +70°C)....1500mW

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

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

ELECTRICAL CHARACTERISTICS

(VIN= 12V, C

REG

= 1µF to GND, I

REG

= 0, R

CS_

= 2Ω from CS_ to GND, TJ= TA= -40°C to +125°C, unless otherwise noted. Typical

values are at T

J

= TA= +25°C.) (Note 1)

Supply Voltage Range V

GND Current I

LED Current-Sense Accuracy
(Note 2)

Dropout Voltage (Note 3) ΔV

Output Current Slew Rate Current rising, V

Output Current Leakage I

CURRENT SENSE

Regulated CS_ Voltage V

OVERTEMPERATURE PROTECTION

Thermal Shutdown Temperature 165 °C

Thermal Shutdown Hysteresis 23 °C

+5V REGULATOR (REG)

Output Voltage V

REG Output Current I

REG Short-Circuit Current I

LOGIC INPUT (PWM1, PWM2, PWM3)

PWM_ Input Bias Current I

PWM_ Input-Voltage High V

PWM_ Input-Voltage Low V

PWM_ Turn-On Delay 50% of V

PWM_ Turn-Off Delay 50% of V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

IN

I

GND

OUT1

10mA < I

10mA < I

I

DO

LEAK

CS_

REGIREG

REG

REGSCVREG

PWM

IH

IL

OUT_

I

OUT_

PWM1 = PWM2 = PWM3 = 0V 1 µA

V

CS1

4.75V < V

V

PWM1

= I

= 100mA (current pulsed) 0.75 1.5

= 150mA (current pulsed) 1.2 2.25

= V

= 0mA (Note 4) 4.75 5 5.25 V

= 0V (Note 5) 15 40 90 mA

= I

OUT2

< 100mA 5

OUT_

< 150mA 7

OUT_

= V

CS2

REG

= V

PWM2

PWM_

PWM_

=100mA 5 10 mA

OUT3

= 4V 100 mA/µs

OUT

CS3

= V

to 50% of ΔV

to 50% of ΔV

= 5V 1 µA

PWM3

OUT_

OUT_

6.5 28.0 V

190 200 210 mV

4mA

4V

0.6 V

475 ns

150 ns

%

V

MAX16824/MAX16825

High-Voltage, Three-Channel Linear

High-Brightness LED Drivers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VIN= 12V, C

REG

= 1µF to GND, I

REG

= 0, R

CS_

= 2Ω from CS_ to GND, TJ= TA= -40°C to +125°C, unless otherwise noted. Typical

values are at T

J

= TA= +25°C.) (Note 1)

OUTPUTS (OUT1, OUT2, OUT3)

Turn-On Time t

Turn-Off Time t

SPI INTERFACE (CLK, LE, OE, DIN, DOUT) (Figures 3 and 4)

DIN, CLK, LE, OE Input Bias
Current

DIN, CLK, LE, OE Input-Voltage
High

DIN, CLK, LE, OE Input-Voltage
Low

CLK Clock Period t

CLK Pulse-Width High t

CLK Pulse-Width Low t

DIN Setup Time t

DIN Hold Time t

DOUT Propagation Delay t

DOUT Rise/Fall Time tDR/t

DOUT Voltage High V

DOUT Voltage Low V

LE Pulse-Width High t

LE Setup Time t

LE Rising to OUT_ Rising Delay t

LE Rising to OUT_ Falling Delay t

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

V

V

CP

CH

CL

DS

DH

DO

DOH

DOL

LW

LS

LRR

LRF

PWM_ rising time, tR, is measured from 20%

R

to 80% of I

PWM_ falling time, tF, is measured from

F

80% to 20% of I

DIN = CLK = LE = OE = 0 or 5V 1 µA

IH

IL

50% of CLK rising to 50% of next CLK
rising, Figure 3

50% of CLK rising to 50% of CLK falling,
Figure 3

50% of CLK falling to 50% of CLK rising,
Figure 3

50% of DIN rising to 50% of CLK rising,
Figure 3

50% of CLK rising to 50% of DIN falling,
Figure 3

50% of CLK rising to 50% of DOUT rising/
falling, Figure 3

C

DOUT

DF

rising/falling edge (Note 6)

I

SOURCE

I

SINK

50% of LE rising to 50% of LE falling,
Figure 3

50% of CLK rising to 50% of LE rising,
Figure 3

50% of LE rising to 50% of OUT_ rising,
Figure 4

50% of LE rising to 50% of OUT_ falling,
Figure 4

OUT

OUT

= 10pF, 10% to 90% of DOUT

= 4mA 4.5 V

= 4mA 0.5 V

1µs

1µs

2.2 V

0.5 V

50 ns

24 ns

24 ns

5ns

10 ns

5ns

15 ns

20 ns

15 ns

150 ns

475 ns

MAX16824/MAX16825

High-Voltage, Three-Channel Linear
High-Brightness LED Drivers

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VIN= 12V, C

REG

= 1µF to GND, I

REG

= 0, R

CS_

= 2Ω from CS_ to GND, TJ= TA= -40°C to +125°C, unless otherwise noted. Typical

values are at T

J

= TA= +25°C.) (Note 1)

Note 1: All devices are 100% production tested at TJ= +25°C and TJ= +125°C. Limits to -40°C are guaranteed by design.
Note 2: This specification does not include sense resistor tolerance and ground error.
Note 3: Dropout is measured as follows: R

SC_

= 1.21Ω from CS_ to GND. Force 100mA into OUT_ and measure the dropout voltage

from OUT_ to CS_. DVDO = (ΔOUT_ - V

CS_

).

Note 4: OUT’s current regulation varies with load across REG (see the

Typical Operating Characteristics

).

Note 5: Overtemperature protection does not function if the output of the 5V reference (REG) is shorted to ground.
Note 6: Guaranteed by design, not production tested.

0

0.2

0.1

0.5

0.4

0.3

0.6

0.7

0.9

0.8

1.0

-40 -10 5-25 203550658095110125

DROPOUT VOLTAGE vs. TEMPERATURE

MAX16824toc01

TEMPERATURE (°C)

DROPOUT VOLTAGE (V)

I

LOAD

= 100mA

0.182

0.192

0.187

0.197

0.202

0.207

0604515 30 75 90 105 120 135 150

CS_ VOLTAGE vs. OUTPUT CURRENT

MAX16824 toc02

OUTPUT CURRENT (mA)

V

CS_

(V)

OUTPUT CURRENT vs. INPUT VOLTAGE

MAX16824 toc03

VIN (V)

OUTPUT CURRENT (mA)

262420 226 8 10 12 14 16 182 4

10

30

50

70

90

110

130

150

170

190

-10
028

I

LOAD

= 150mA

I

LOAD

= 100mA

Typical Operating Characteristics

(VIN= 12V, C

REG

= 1µF to GND, I

REG

= 0, R

CS_

= 2Ω from CS_ to GND, TA= +25°C, unless otherwise noted. Typical values are at

TA= +25°C.)

CLK Rising to OUT_ Rising Delay t

CLK Rising to OUT_ Falling Delay t

OE Rising to OUT_ Rising Delay t

OE Falling to OUT_ Falling Delay t

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CRR

CRF

OEH

OEL

50% of CLK rising to 50% of OUT_ rising,
Figure 4

50% of CLK rising to 50% of OUT_ falling,
Figure 4

50% of OE rising to 50% of OUT_ rising,
Figure 3

50% of OE falling to 50% of OUT_ falling,
Figure 3

150 ns

475 ns

150 ns

475 ns

MAX16824/MAX16825

High-Voltage, Three-Channel Linear

High-Brightness LED Drivers

______________________________________________________________________________________________________________________________________________________________________________

5

Typical Operating Characteristics (continued)

(VIN= 12V, C

REG

= 1µF to GND, I

REG

= 0, R

CS_

= 2Ω from CS_ to GND, TA= +25°C, unless otherwise noted. Typical values are at

T

A

= +25°C.)

OUTPUT CURRENT vs. TEMPERATURE

200

180

160

140

120

100

80

60

OUTPUT CURRENT (mA)

40

20

0

-40 -10 5-25 203550658095110125

CS_ VOLTAGE vs. REG OUTPUT CURRENT

0.200

0.199

0.198

0.197

0.196

0.195

0.194

0.193

0.192

(V)

0.191

CS_

V

0.190

0.189

0.188

0.187

0.186

0.185

0.184

0.183

0.182
010

I

= 150mA

OUT

I

= 95mA

OUT

I

= 10mA

OUT

TEMPERATURE (°C)

I

LOAD

I

LOAD

I

(mA)

REG

= 100mA

= 150mA

986 72 3 4 51

MAX16824toc04

MAX16824 toc07

(V)

V

3.45

3.25

3.05

2.85

2.65

SUPPLY CURRENT (mA)

2.45

2.25

-40 125

OUTPUT VOLTAGE vs. INPUT VOLTAGE

5.000

4.995

4.990

4.985

4.980

REG

4.975

4.970

4.965

4.960
028

SUPPLY CURRENT

vs. TEMPERATURE

VIN = 28V

VIN = 6.5V

V

= V

PWM

PWM

TEMPERATURE (°C)

I

= 0

REG

I

= 1mA

REG

I

= 4mA

REG

VIN (V)

OUTPUT VOLTAGE vs. TEMPERATURE

5.10

5.08

MAX16824 toc05

5.06

5.04

5.02

(V)

5.00

REG

V

4.98
I

= 4mA

LOAD

4.96

4.94

= V

= 0

PWM

1109580655035205-10-25

4.92

4.90

TEMPERATURE (°C)

LED CURRENT FALL TIME

MAX16824 toc08

24204 8 12 16

I

LOAD

I

= 1mA

LOAD

I

LED

V

IN

PULSED AT 200Hz
(50% DUTY CYCLE)

2

μs/div

= 0

= 150mA

= 12V

MAX16824 toc09

1109580655035205-10-25-40 125

MAX16824 toc06

V

PWM_

2V/div

0V

I

OUT_

100mA/div

0A

LED CURRENT RISE TIME

I

= 150mA

LED

= 12V

V

IN

PULSED AT 200Hz
(50% DUTY CYCLE)

2μs/div

MAX16824 toc10

V

PWM_

2V/div

0V

I

OUT_

100mA/div

0A

330Hz DIMMED OPERATION

20μs/div

MAX16824 toc11

I

= 150mA

LOAD

= 12V

V

IN

PWM_ PULSED
AT 330Hz
(1% DUTY CYCLE)

V

PWM_

2V/div

0V

I

OUT_

100mA/div

0A