MAXIM MAX16807, MAX16808 Technical data

General Description

The MAX16807/MAX16808 are integrated, high-efficien­cy white or RGB LED drivers. They are designed for
LCD backlighting and other LED lighting applications
with multiple strings of LEDs. The MAX16807/
MAX16808’s current-mode PWM controller regulates
the necessary voltage to the LED array. Depending on
the input voltage and LED voltage range, it can be
used with boost or buck-boost (SEPIC) topologies. The
MAX16807/MAX16808 feature an 8V to 26.5V input volt­age range. A wide range of adjustable frequency
(20kHz to 1MHz) allows design optimization for efficien­cy and minimum board space.

The MAX16807/MAX16808 LED drivers include eight
open-drain, constant-current-sinking LED driver outputs
rated for 36V continuous operation. The LED current­control circuitry achieves ±3% current matching among
strings and enables paralleling of outputs for LED string
currents higher than 55mA. The output-enable pin is
used for simultaneous PWM dimming of all output chan­nels. Dimming frequency range is 50Hz to 30kHz and
dimming ratio is up to 5000:1. The constant-current out­puts are single resistor programmable and the LED cur­rent can be adjusted up to 55mA per output channel.

The MAX16807/MAX16808 operate either in stand-alone
mode or with a microcontroller (µC) using an industry­standard, 4-wire serial interface. The MAX16808 includes
circuitry that automatically detects open-circuit LEDs.

The MAX16807/MAX16808 include overtemperature
protection, operate over the full -40°C to +125°C tem­perature range, and are available in a thermally
enhanced, 28-pin TSSOP exposed paddle package.

Features

o Eight Constant-Current Output Channels (Up to

55mA Each)

o ±3% Current Matching Among Outputs
o Paralleling Channels Allows Higher Current per

LED String

o Outputs Rated for 36V Continuous Voltage
o Output-Enable Pin for PWM Dimming (Up to 30kHz)
o One Resistor Sets LED Current for All Channels
o Wide Dimming Ratio Up to 5000:1
o Low Current-Sense Reference (300mV) for High

Efficiency

o 8V to 26.5V Input Voltage or Higher with External

Biasing Devices

o Open LED Detection (MAX16808)
o 4-Wire Serial Interface to Control Individual

Output Channels

Applications

LCD White or RGB LED Backlighting:

LCD TVs, Desktop, and Notebook Panels
Automotive Navigation, Heads-Up,
and Infotainment Displays
Industrial and Medical Displays

Ambient, Mood, and Accent Lighting

MAX16807/MAX16808

Integrated 8-Channel LED Drivers with

Switch-Mode Boost and SEPIC Controller

________________________________________________________________

Maxim Integrated Products

1

19-0655; Rev 1; 4/07

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

Pin Configurations appear at end of data sheet.

Ordering Information

Typical Operating Circuits

+

Denotes a lead-free package.

*

EP = Exposed paddle.

Typical Operating Circuits continued at end of data sheet.

V

3V TO 5.5V

IN

R

SET

C

IN

C

BYP

L

Q

R

OUT CS AGND COMP

V

CC

V+

PGND

MAX16807

LE

MAX16808

DIN

CLK
DOUT
OE

SET

REF

R

C

REF

D

C

CS

C

C1

RTCT

T

C

T

PA R T

M A X1 6 8 0 7 AU I+ - 40°C to + 125°C 28 TS S O P - E P *U 28M E - 1

M A X1 6 8 0 8 AU I+ - 40°C to + 125°C 28 TS S O P - E P *U 28M E - 1

T EM P

R A N G E

PIN - PA C K A G E

V

OUT

C

OUT

R1

C2

R

C1

R2

FB

OUT0
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
OUT7

STAND-ALONE OPERATION

LEDs

PK G

C O D E

MAX16807/MAX16808

Integrated 8-Channel LED Drivers with
Switch-Mode Boost and SEPIC Controller

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS (PWM CONTROLLER)

(VCC= +15V, V+ = +3V to +5.5V referenced to PGND, RT= 10kΩ, CT= 3.3nF, REF = open, COMP = open, C

REF

= 0.1µF, VFB= 2V,

CS = AGND, AGND = PGND = 0V; all voltages are measured with respect to AGND, unless otherwise noted. T

J

= TA = -40°C to

+125°C, unless otherwise noted. Typical values are at T

A

= +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.

VCCto AGND..........................................................-0.3V to +30V

Current into V

CC (VCC

> 24V)...........................................±30mA

V+ to PGND..............................................................-0.3V to +6V

OUT to AGND.............................................-0.3V to (V

CC

+ 0.3V)

OUT Current (10µs duration) .................................................±1A

FB, COMP, CS, RTCT, REF to AGND.......................-0.3V to +6V

COMP Sink Current.............................................................10mA

OUT0–OUT7 to PGND............................................-0.3V to +40V

DIN, CLK, LE, OE, SET to PGND..................-0.3V to (V+ + 0.3V)

DOUT Current...................................................................±10mA

OUT0–OUT7 Sink Current...................................................60mA

Total PGND Current ..........................................................480mA

Continuous Power Dissipation (T

A

= +70°C)

28-Pin TSSOP (derate 27mW/°C* above +70°C).......2162mW

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

*

Per JEDEC51 Standard (Multilayer Board).

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

REFERENCE

Output Voltage V

Line Regulation ΔV

Load Regulation ΔV

Total Output-Voltage Variation V

Output Noise Voltage V

Output Short-Circuit Current I

REF

LINE

LOAD

REFT

NOISE

SHORT

OSCILLATOR

Initial Accuracy TJ = +25°C 51 54 57 kHz

Voltage Stability 12V < VCC < 25V 0.2 0.5 %

Temperature Stability 1%

RTCT Ramp Peak-to-Peak 1.7 V

RTCT Ramp Valley 1.1 V

Discharge Current I

Frequency Range f

DIS

OSC

ERROR AMPLIFIER

FB Input Voltage V

Input Bias Current I

Open-Loop Gain A

Unity-Gain Bandwidth f

FB

B(FB)

VOL

GBW

Power-Supply Rejection Ratio PSRR 12V ≤ VCC ≤ 25V 60 80 dB

COMP Sink Current I

COMP Source Current I

COMP Output-Voltage High V

COMP Output-Voltage Low V

SINK

SOURCE

OH

OL

I

= 1mA, T

REF

12V< V

CC

1mA < I

REF

(Note 2) 4.875 5.125 V

10Hz < f < 10kHz 50 µV

V

= 0V 30 180 mA

REF

V

= 2V, TJ = +25°C 7.9 8.3 8.7

RTCT

V

= 2V, -40oC ≤ TJ ≤ +125°C 7.5 8.3 9.0

RTCT

FB shorted to COMP 2.45 2.50 2.55 V

2V ≤ V

COMP

VFB = 2.7V, V

VFB = 2.3V, V

VFB = 2.3V, R

VFB = 2.7V, R

= +25°C 4.95 5 5.05 V

J

< 25V, I

= 1mA 0.4 4 mV

REF

< 20mA 6 50 mV

20 1000 kHz

-0.01 -0.1 µA

≤ 4V 100 dB

1 MHz

= 1.1V 2 6 mA

COMP

= 5V 0.5 1.2 1.8 mA

COMP

= 15kΩ to AGND 5 5.8 V

COMP

COMP

= 15kΩ to V

REF

0.1 1.1 V

mA

MAX16807/MAX16808

Integrated 8-Channel LED Drivers with

Switch-Mode Boost and SEPIC Controller

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (PWM CONTROLLER) (continued)

(VCC= +15V, V+ = +3V to +5.5V referenced to PGND, RT= 10kΩ, CT= 3.3nF, REF = open, COMP = open, C

REF

= 0.1µF, VFB= 2V,

CS = AGND, AGND = PGND = 0V; all voltages are measured with respect to AGND, unless otherwise noted. T

J

= TA = -40°C to

+125°C, unless otherwise noted. Typical values are at T

A

= +25°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CURRENT-SENSE AMPLIFIER

Current-Sense Gain A

Maximum Current-Sense Signal V

Power-Supply Rejection Ratio PSRR 12V ≤ VCC ≤ 25V 70 dB

Current-Sense Input Bias Current I

Current Sense to OUT Delay t

MOSFET DRIVER

OUT Low-Side On-Resistance V

OUT High-Side On-Resistance V

Source Current (Peak) I

Sink Current (Peak) I

Rise Time t

Fall Time t

UNDERVOLTAGE LOCKOUT/STARTUP

Startup Voltage Threshold V

Minimum Operating Voltage After
Turn-On

Undervoltage-Lockout Hysteresis UVLO

PULSE-WIDTH MODULATION (PWM)

Maximum Duty Cycle D

Minimum Duty Cycle D

SUPPLY CURRENT

Startup Supply Current I

Operating Supply Current I

VCC Zener Voltage V

CS

CS_MAX

CS

PWM

RDS_ONL

RDS_ONH

SOURCE

SINK

R

F

CC_START

V

CC_MIN

HYST

MAX

MIN

START

CC

Z

(Notes 3, 4) 2.85 3.00 3.40 V/V

(Note 3) 0.275 0.300 0.325 V

V

= 0V -1 -2.5 µA

COMP

50mV overdrive 60 ns

I

= 200mA

SINK

I
100mA

C

C

C

C

VCC = 7.5V 32 65 µA

VFB = VCS = 0V 3 5 mA

ICC = 25mA 24 26.5 V

=

SOURCE

= 10nF 2 A

LOAD

= 10nF 1 A

LOAD

= 1nF 15 ns

LOAD

= 1nF 22 ns

LOAD

TJ = -40°C to +85°C (Note 2) 4.5 10

= -40°C to +125°C 4.5 12

T

J

TJ = -40°C to +85°C (Note 2) 3.5 7.5

T

= -40°C to +125°C 3.5 10

J

7.98 8.4 8.82 V

7.1 7.6 8.0 V

94.5 96 97.5 %

0.8 V

0%

Ω

Ω

MAX16807/MAX16808

Integrated 8-Channel LED Drivers with
Switch-Mode Boost and SEPIC Controller

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (LED DRIVER)

(V+ = +3V to +5.5V, AGND = PGND = 0V; all voltages are measured with respect to PGND, unless otherwise noted. TA= TJ= -40°C
to +125°C, unless otherwise noted. Typical values are at T

A

= +25°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Operating Supply Voltage V+ 3.0 5.5 V

Output Voltage V

Standby Current (Interface Idle, All
Output Ports High Impedance)

Standby Current
(Interface Active, All Output Ports
High Impedance)

OUT_

R
OE = V+, DOUT unconnected

R
DIN, LE = PGND or V+, DOUT unconnected

= 360Ω, DIN, LE, CLK = PGND or V+,

SET

= 360Ω, f

SET

= 5MHz, OE = V+,

CLK

36 V

3.6 4.5 mA

3.8 4.8 mA

Supply Current
(Interface Idle, All Output Ports
Active Low)

INTERFACE (DIN, CLK, DOUT, LE, OE)

Input-Voltage High
(DIN, CLK, LE, OE)

Input-Voltage Low
(DIN, CLK, LE, OE)

Hysteresis Voltage
(DIN, CLK, LE, OE)

Input Leakage Current
(DIN, CLK)

OE Pullup Current to V+ I

LE Pulldown Current to PGND I

Output-Voltage High (DOUT) V

Output-Voltage Low (DOUT) V

OUT_ Output Current I

OUT_ Leakage Current OE = V+ 1 µA

OUT_ Fault Detection Threshold
(MAX16808)

I+

V

V

V

HYST

I

LEAK

OE

OUT_

V

OUTTH

R

= 360Ω, OE = PGND, DIN,

SET

LE = V+, DOUT unconnected

IH

IL

V+ = 5.5V, OE = PGND 0.25 1.5 25.0 µA

V+ = 5.5V, LE = V+ 0.25 1.5 25.0 µA

LE

I

OH

I

OL

0oC ≤ TA ≤ +125°C, V
360Ω

TA = -40°C, V
R

V+ = 5.5V, OE = V+ 0.8 V

= 4mA

SOURCE

= 4mA 0.5 V

SINK

= 1V to 2.5V, R

SET

= 360Ω

= 1V to 2.5V,

OUT

OUT

SET

0.7

x V+

-1 +1 µA

V+

- 0.5V

=

46.5 50 53.5

43 57

17 30 mA

0.8 V

0.3

x V+

V

V

V

mA

MAX16807/MAX16808

Integrated 8-Channel LED Drivers with

Switch-Mode Boost and SEPIC Controller

_______________________________________________________________________________________ 5

5V TIMING CHARACTERISTICS

(V+ = +4.5V to +5.5V, AGND = PGND = 0V; all voltages are measured with respect to PGND, unless otherwise noted. TA= TJ= -40°C
to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 5)

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS

INTERFACE TIMING CHARACTERISTICS

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 Time t

DOUT Fall Time t

LE Pulse-Width High t

LE Setup Time t

LE Rising to OUT_ Rising Delay t

LE Rising to OUT_ Falling Delay t

CLK Rising to OUT_ Rising Delay t

CLK Rising to OUT_ Falling
Delay

OE Rising to OUT_ Rising Delay t
OE Falling to OUT_ Falling Delay t

OUT_ Turn-On Fall Time t

OUT_ Turn-Off Rise Time t

CH

DH

DO

DR

LW

LRR

LRF

CRR

t

CRF

OER

OEF

CP

CL

DS

DF

LS

C

= 10pF, 20% to 80% 10 ns

DOUT

C

= 10pF, 80% to 20% 10 ns

DOUT

(Note 6) 110 ns

(Note 6) 325 ns

(Note 6) 110 ns

(Note 6) 325 ns

(Note 6) 110 ns

(Note 6) 325 ns

F

R

80% to 20% (Note 6) 210 ns

20% to 80% (Note 6) 130 ns

40 ns

19 ns

19 ns

4ns

8ns

12 50 ns

20 ns

15 ns

MAX16807/MAX16808

Integrated 8-Channel LED Drivers with
Switch-Mode Boost and SEPIC Controller

6 _______________________________________________________________________________________

3.3V TIMING CHARACTERISTICS

(V+ = +3V to < +4.5V, AGND = PGND = 0V; all voltages are measured with respect to PGND, unless otherwise noted. TA= TJ= -40°C
to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Notes 1, 5)

Note 1: All devices are 100% production tested at TJ= +25°C and +125°C. Limits to -40°C are guaranteed by design.
Note 2: Guaranteed by design, not production tested.
Note 3: Parameter is measured at trip point of latch with V

FB

= 0V.

Note 4: Gain is defined as A = ΔV

COMP

/ ΔVCS, 0.05V ≤ VCS≤ 0.25V.

Note 5: See Figures 3 and 4.
Note 6: A 65Ω pullup resistor is connected from OUT_ to 5.5V. Rising refers to V

OUT_

when current through OUT_ is turned off and

falling refers to V

OUT_

when current through OUT_ is turned on.

PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS

INTERFACE TIMING CHARACTERISTICS

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 Time t

DOUT Fall Time t

LE Pulse-Width High t

LE Setup Time t

LE Rising to OUT_ Rising Delay t

LE Rising to OUT_ Falling Delay t

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

OUT_ Turn-On Fall Time t

OUT_ Turn-Off Rise Time t

CP

CH

CL

DS

DH

DO

DR

DF

LW

LS

LRR

LRF

CRR

CRF

OER

OEF

F

R

C

DOUT

C

DOUT

(Note 6) 140 ns

(Note 6) 350 ns

(Note 6) 140 ns

(Note 6) 350 ns

(Note 6) 140 ns

(Note 6) 350 ns

80% to 20% (Note 6) 275 ns

20% to 80% (Note 6) 150 ns

= 10pF, 20% to 80% 12 ns

= 10pF, 80% to 20% 12 ns

52 ns

24 ns

24 ns

4ns

8ns

12 70 ns

20 ns

15 ns

MAX16807/MAX16808

Integrated 8-Channel LED Drivers with

Switch-Mode Boost and SEPIC Controller

_______________________________________________________________________________________

7

)

(°C)

V

(V)

Typical Operating Characteristics

(VCC= +15V, V+ = 3V to 5.5V, RT= 10kΩ, CT= 3.3nF, V

REF

= COMP = open, C

REF

= 0.1µF, VFB= 2V, CS = AGND = PGND = 0V.

Typical values are at TA= +25°C, unless otherwise noted.)

BOOTSTRAP UVLO vs. TEMPERATURE

10

9

8

7

6

(V)

5

CC

V

4

3

2

1

0

-40 125

TEMPERATURE (°C)

VCC RISING

VCC FALLING

HYSTERESIS

1109565 80-10 5 20 35 50-25

MAX16807 toc01

41

VCC = 7.5V

39

37

35

(μA)

33

CC

I

31

29

27

25

-40 -10 5 20-25 35 50 9580 11065 125

REFERENCE VOLTAGE

5.08

vs. TEMPERATURE

5.06

5.04

5.02

I

5.00

(V)

REF

V

4.98

4.96

4.94

4.92

4.90

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

REF

I

REF

= 1mA

= 20mA

MAX16807 toc04

(V)

V

REF

vs. REFERENCE LOAD CURRENT

5.05

5.00

4.95

4.90

4.85

4.80

4.75

4.70

4.65
02010 30 40 50 60 70

STARTUP CURRENT

vs. TEMPERATURE

TEMPERATURE (°

REFERENCE VOLTAGE

I

(mA)

REF

OPERATING SUPPLY CURRENT

vs. TEMPERATURE AFTER STARTUP

5.1

4.9

MAX16807 toc02

4.7

4.5

(mA)

4.3

CC

I

4.1

3.9

3.7

3.5

-40 -10 5 20-25 35 50 9580 11065 125

C

5.000
I

REF

4.998

4.996

MAX16807 toc05

4.994

4.992

4.990

REF

4.988

4.986

4.984

4.982

4.980

10 14 1612 18 20 22 24 26

= fSW = 300kHz)

(f

OSC

TEMPERATURE

REFERENCE VOLTAGE
vs. SUPPLY VOLTAGE

= 1mA

VCC (V)

CT = 560pF

MAX16807 toc03

MAX16807 toc06

OSCILLATOR FREQUENCY (f

vs. TEMPERATURE

550

RT = 3.65kΩ

540

= 560pF

C

T

530

520

510

500

490

480

OSCILLATOR FREQUENCY (kHz)

470

460

450

-40 -10 5-25 203550658095110125

TEMPERATURE (°C)

OSC

)

OSCILLATOR RT/CT DISCHARGE CURRENT

vs. TEMPERATURE

8.04
V

= 2V

RT/CT

8.02

MAX16807 toc07

8.00

7.98

7.96

7.94

DISCHARGE CURRENT (mA)

T

7.92

/C

T

R

7.90

7.88

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

MAX16807 toc08

CURRENT-SENSE TRIP THRESHOLD

vs. TEMPERATURE

0.40

0.38

0.36

0.34

0.32

0.30

0.28

CS THRESHOLD (V)

0.26

0.24

0.22

0.20

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

MAX16807 toc09