Datasheet

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General Description

The MAX16807 is an integrated, high-efficiency white or

RGB LED driver. It is designed for LCD backlighting and

other LED lighting applications with multiple strings of LEDs.

The MAX16807 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 features

an 8V to 26.5V input voltage range. A wide range of adjust-

able frequency (20kHz to 1MHz) allows design optimization

for efficiency and minimum board space.

The MAX16807 LED driver includes eight open-drain,

constant-current-sinking LED driver outputs rated for

36V continuous operation. The LED current-control

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 operates either in stand-alone mode or

with a microcontroller (μC) using an industry-standard,

4-wire serial interface.

The MAX16807 includes overtemperature protection,

operates over the full -40°C to +125°C temperature

range, and is available in a thermally enhanced, 28-pin

TSSOP exposed pad package.

Features

● Eight Constant-Current Output Channels (Up to

55mA Each)

● ±3% Current Matching Among Outputs

● Paralleling Channels Allows Higher Current per LED

String

● Output Rated for 36V Continuous Voltage

● Output-Enable Pin for PWM Dimming (Up to 30kHz)

● One Resistor Sets LED Current for All Channels

● Wide Dimming Ratio Up to 5000:1

● Low Current-Sense Reference (300mV) for High

Efficiency

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

Biasing Devices

● 4-Wire Serial Interface to Control Individual Output

Channels

Applications

● LCD White or RGB LED Backlighting:

LCD TVs, Desktop and Notebook Panels,

Industrial and Medical Displays

● Ambient, Mood, and Accent Lighting

Pin Configuration appears at end of data sheet.

Typical Operating Circuits continued at end of data sheet.

19-0655; Rev 3; 11/14

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

*EP = Exposed pad.

PART TEMP RANGE PIN-PACKAGE

MAX16807AU I+ - 40°C to + 125°C 28 TSSOP-EP*

MAX16807

OUT0

OUT1

OUT2

OUT3

OUT4

OUT5

OUT6

OUT7

SET

DIN

PGND

V+

DOUT

CLK

REF

RTCT

REF

SET

BYP

OUT CS AGN COMP

OUT

3V TO 5.5V

OUT

LEDs

STAND-ALONE OPERATION

MAX16807 Integrated 8-Channel LED Driver with

Switch-Mode Boost and SEPIC Controller

Typical Operating Circuits

Ordering Information

EVALUATION KIT AVAILABLE

Summary of content (19 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller General Description Features The MAX16807 is an integrated, high-efficiency white or RGB LED driver. It is designed for LCD backlighting and other LED lighting applications with multiple strings of LEDs. The MAX16807 current-mode PWM controller regulates the necessary voltage to the LED array.
PAGE 2
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Absolute Maximum Ratings VCC to AGND..........................................................-0.3V to +30V Current into VCC (VCC > 24V)..........................................±30mA V+ to PGND..............................................................-0.3V to +6V OUT to AGND.............................................-0.3V to (VCC + 0.3V) OUT Current (10μs duration)..................................................
PAGE 3
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Electrical Characteristics (PWM Controller) (continued) (VCC = +15V, V+ = +3V to +5.5V referenced to PGND, RT = 10kΩ, CT = 3.3nF, REF = open, COMP = open, CREF = 0.1μF, VFB = 2V, CS = AGND, VAGND = VPGND = 0V; all voltages are measured with respect to AGND, unless otherwise noted. TJ = TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 4
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Electrical Characteristics (LED Driver) (V+ = +3V to +5.5V, VAGND = VPGND = 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.) (Note 1) PARAMETER Operating Supply Voltage Output Voltage SYMBOL CONDITIONS V+ MIN TYP 3.0 VOUT_ MAX UNITS 5.
PAGE 5
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller 5V Timing Characteristics (V+ = +4.5V to +5.5V, VAGND = VPGND = 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.
PAGE 6
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller 3.3V Timing Characteristics (V+ = +3V to < +4.5V, VAGND = VPGND = 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.
PAGE 7
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Typical Operating Characteristics (VCC = +15V, V+ = 3V to 5.5V, RT = 10kΩ, CT = 3.3nF, VREF = COMP = open, CREF = 0.1μF, VFB = 2V, VCS = VAGND = VPGND = 0V. Typical values are at TA = +25°C, unless otherwise noted.) 6 5 4 3 2 HYSTERESIS 1 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) 3.9 27 3.7 4.98 4.85 4.92 4.70 4.90 4.
PAGE 8
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Typical Operating Characteristics (continued) (VCC = +15V, V+ = 3V to 5.5V, RT = 10kΩ, CT = 3.3nF, VREF = COMP = open, CREF = 0.1μF, VFB = 2V, VCS = VAGND = VPGND = 0V. Typical values are at TA = +25°C, unless otherwise noted.) 0.1 10k 100k 1M FREQUENCY (Hz) 10M PROPAGATION DELAY FROM CURRENT-LIMIT COMPARATOR TO OUT vs.
PAGE 9
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Typical Operating Characteristics (continued) (VCC = +15V, V+ = 3V to 5.5V, RT = 10kΩ, CT = 3.3nF, VREF = COMP = open, CREF = 0.1μF, VFB = 2V, VCS = VAGND = VPGND = 0V. Typical values are at TA = +25°C, unless otherwise noted.) TA = +85°C 3.60 TA = +25°C TA =-40°C 3.55 TA = +125°C TA = +85°C 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 5 5.5 19 16 TA = -40°C 3.0 3.5 TA = +25°C 4.0 4.5 5.
PAGE 10
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Typical Operating Characteristics (continued) (VCC = +15V, V+ = 3V to 5.5V, RT = 10kΩ, CT = 3.3nF, VREF = COMP = open, CREF = 0.1μF, VFB = 2V, VCS = VAGND = VPGND = 0V. Typical values are at TA = +25°C, unless otherwise noted.) OUT_ CURRENT vs. OUT_ VOLTAGE (RSET = 360Ω, V+ = 5.0V) 40 OUT_ CURRENT (mA) TA = -40°C TA = +25°C 30 TA = +85°C 20 TA = +125°C MAX16807 toc25 50 OUT_ CURRENT (mA) 26.
PAGE 11
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Pin Description PIN NAME FUNCTION 1, 13, 28 N.C. 2 AGND 3 OUT MOSFET Driver Output OUT. Connects to the gate of the external n-channel MOSFET. 4 VCC Power-Supply Input. Bypass VCC to AGND with a 0.1µF ceramic capacitor or a parallel combination of a 0.1µF and a higher value ceramic capacitor. REF 5V Reference Output. Bypass REF to AGND with a 0.1µF ceramic capacitor. 5 6–9 No Connection.
PAGE 12
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller nected in series. The constant-current capability is up to 55mA per output, set for all eight outputs by an external resistor (RSET). The device can operate in stand-alone mode (see the Typical Operating Circuits.) The number of channels can be expanded by using the MAX6970 and MAX6971 family in conjunction with the MAX16807. MAX16807 UVLO REFERENCE 2.5V VOLTAGEDIVIDER PREREG 5V VCC 26.
PAGE 13
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller V+ 68W/L 1.23V W/L OUT_ 1.23 REST 995R R SET PGND Figure 1b. OUT_ Driver Internal Diagram Switch-Mode Controller Current-Mode Control Loop The advantages of current-mode control over voltagemode control are twofold. First, there is the feed-forward characteristic brought on by the controller’s ability to adjust for variations in the input voltage on a cycle-bycycle basis.
PAGE 14
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller The oscillator frequency is then: OSC (t C R CS = tD) Reference Output (REF) REF is a 5V reference output that can source 20mA. Bypass REF to AGND with a 0.1μF capacitor. Current Limit The MAX16807 includes a fast current-limit comparator to terminate the on-cycle during an overload or a fault condition.
PAGE 15
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller LED Driver shifts data out from the MAX16807’s 8-bit shift register on the rising edge of CLK. Data at DIN propagates through the shift register and appears at DOUT eight clock cycles later. Table 1 shows the 4-wire serial-interface truth table. 4-Wire Interface The MAX16807 also operates in stand-alone mode (see the Typical Operating Circuits).
PAGE 16
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller LE tLW tCL tCH tLS tCP CLK tDS tDH D0 D7 DIN tDO D7 DOUT tOEW OE tOEF 80% OUT_ tOER 20% tf tr Figure 3. 4-Wire Serial-Interface Timing Diagram Stand-Alone Operation LE tLRF OUT_ LE tLRR OUT_ CLK LED Dimming PWM Dimming tCRF OUT_ CLK tCRR OUT_ Figure 4. LE and CLK to OUT_ Timing www.maximintegrated.
PAGE 17
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Computing Power Dissipation Use the following equation to estimate the upper-limit power dissipation (PD) for the MAX16807: i=7   = PD DUTY × (V + × I +) + ∑ VOUTi × I OUTi  + (VCC × I CC )   i=0 where: V+ = Supply voltage I+ = Operating supply current DUTY = PWM duty cycle applied to OE VOUTi = MAX16807 port output voltage when driving load LED(s) IOUTi = LED drive current programmed by RSET PD = Power dissipat
PAGE 18
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Typical Operating Circuits (continued) VIN L VOUT D COUT Q LEDs R1 CC2 RCS CC1 RC1 R2 OUT CS AGND COMP VCC FB CIN 3V TO 5.
PAGE 19
MAX16807 Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 10/06 Initial release 1 4/07 Release of the MAX16808 2 8/09 Removal of the MAX16808 from the data sheet.