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19-1107; Rev 0; 11/07
High-Voltage, Three-Channel Linear High-Brightness LED Drivers
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 2Mbps, 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 -40C to +85C temperature range.
Features
6.5V to 28V Operating Range Outputs Connected to 36V Supply for Long LED Strings Three 36V-Rated Output Channels with Independently Adjustable LED Current 150mA Output Current Per Channel 5% LED Current Accuracy PWM Dimming Three Independent Dimming Control Inputs (MAX16824) 4-Wire Serial Interface LED Current Chopping (MAX16825) +5V (5%) Regulated Output with 4mA Source Capability Fast Transient Dimming Response 200mV Current-Sense Reference Reduces Power Loss Thermal Shutdown -40C to +85C Operating Temperature Range Thermally Enhanced, 16-Pin TSSOP Exposed Paddle Package
MAX16824/MAX16825
Ordering Information
PART MAX16824EUE+ MAX16825EUE+ TEMP RANGE -40C to +85C -40C to +85C PIN PACKAGE 16 TSSOP-EP* 16 TSSOP-EP* PKG CODE U16E-3 U16E-3
Applications
Industrial Lighting Architectural and Decorative Lighting Mood Lighting Indoor and Outdoor LED Video Displays Automotive Lighting LCD Display Backlighting
+Denotes a lead-free package. *EP = Exposed paddle.
Pin Configurations appear at end of data sheet.
Typical Operating Circuits
UP TO 36V VIN
VIN UP TO 36V CIN
CIN
3
3 7 8 9 4 CREG 11
IN PWM1 MAX16824
OUT1
1
6
IN
MAX16825
CLK DIN
OUT1
1
OUT2 PWM2
16
MICROCONTROLLER
7 8
OUT2 OUT3
16 12
PWM3 REG GND
OUT3 CS1 CS2 CS3
12 2 15 13 RCS2 RCS3 RCS1
CREG 9
LE OE 4 REG
CS1 CS2
2 15 RCS1 RCS2
11
CS3 GND
13
RCS3
________________________________________________________________ Maxim Integrated Products
1
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High-Voltage, Three-Channel Linear High-Brightness LED Drivers MAX16824/MAX16825
ABSOLUTE MAXIMUM RATINGS
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 (TA = +70C) 16-Pin TSSOP-EP (derate 18.9mW/C above +70C)....1500mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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.
ELECTRICAL CHARACTERISTICS
(VIN = 12V, CREG = 1F to GND, IREG = 0, RCS_ = 2 from CS_ to GND, TJ = TA = -40C to +85C, unless otherwise noted. Typical values are at TJ = TA = +25C.) (Note 1)
PARAMETER Supply Voltage Range GND Current LED Current-Sense Accuracy (Note 2) SYMBOL VIN IGND IOUT1 = IOUT2 = IOUT3 =100mA 10mA < IOUT_ < 100mA, 0C TJ 85C 10mA < IOUT_ < 100mA, -40C TJ 85C VDO IOUT_ = 100mA (current pulsed) IOUT_ = 150mA (current pulsed) Current rising, VOUT = 4V ILEAK PWM1 = PWM2 = PWM3 = 0V VCS1 = VCS2 = VCS3 , 0C TJ +85C VCS1 = VCS2 = VCS3 , -40C TJ +85C 190 186 200 200 165 23 VREG IREG IREGSC IPWM VIH VIL 50% of VPWM_ to 50% of VOUT_ 50% of VPWM_ to 50% of VOUT_ IREG = 0mA (Note 4) 4.75V < VREG VREG = 0V (Note 5) VPWM1 = VPWM2 = VPWM3 = 5V 4 0.6 475 150 4.75 4 15 40 90 1 5 5.25 0.75 1.2 100 1 210 214 CONDITIONS MIN 6.5 5 TYP MAX 28.0 10 5 % 7 1.5 2.25 V mA/s A UNITS V mA
Dropout Voltage (Note 3) Output Current Slew Rate Output Current Leakage CURRENT SENSE Regulated CS_ Voltage OVERTEMPERATURE PROTECTION Thermal Shutdown Temperature Thermal Shutdown Hysteresis +5V REGULATOR (REG) Output Voltage REG Output Current REG Short-Circuit Current PWM_ Input Bias Current PWM_ Input-Voltage High PWM_ Input-Voltage Low PWM_ Turn-On Delay PWM_ Turn-Off Delay
VCS_
mV
C C V mA mA A V V ns ns
LOGIC INPUT (PWM1, PWM2, PWM3)
2
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High-Voltage, Three-Channel Linear High-Brightness LED Drivers
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 12V, CREG = 1F to GND, IREG = 0, RCS_ = 2 from CS_ to GND, TJ = TA = -40C to +85C, unless otherwise noted. Typical values are at TJ = TA = +25C.) (Note 1)
PARAMETER OUTPUTS (OUT1, OUT2, OUT3) Turn-On Time Turn-Off Time tR tF PWM_ rising time, tR, is measured from 20% to 80% of IOUT PWM_ falling time, tF, is measured from 80% to 20% of IOUT 1 1 s s SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX16824/MAX16825
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 CLK Pulse-Width High CLK Pulse-Width Low DIN Setup Time DIN Hold Time DOUT Propagation Delay DOUT Rise/Fall Time DOUT Voltage High DOUT Voltage Low LE Pulse-Width High LE Setup Time LE Rising to OUT_ Rising Delay LE Rising to OUT_ Falling Delay VIH VIL tCP tCH tCL tDS tDH tDO tDR/tDF VDOH VDOL tLW tLS tLRR tLRF 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 CDOUT = 10pF, 10% to 90% of DOUT rising/falling edge (Note 6) ISOURCE = 4mA ISINK = 4mA 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 20 15 150 475 4.5 0.5 50 24 24 5 10 5 15 DIN = CLK = LE = OE = 0 or 5V 2.2 0.5 1 A V V ns ns ns ns ns ns ns V V ns ns ns ns
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High-Voltage, Three-Channel Linear High-Brightness LED Drivers MAX16824/MAX16825
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 12V, CREG = 1F to GND, IREG = 0, RCS_ = 2 from CS_ to GND, TJ = TA = -40C to +85C, unless otherwise noted. Typical values are at TJ = TA = +25C.) (Note 1)
PARAMETER CLK Rising to OUT_ Rising Delay CLK Rising to OUT_ Falling Delay OE Rising to OUT_ Rising Delay OE Falling to OUT_ Falling Delay SYMBOL tCRR tCRF tOEH tOEL CONDITIONS 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 MIN TYP MAX 150 475 150 475 UNITS ns ns ns ns
Note 1: All devices are 100% production tested at TJ = +25C and TJ = +85C. Limits to -40C are guaranteed by design. Note 2: This specification does not include sense resistor tolerance and ground error. Note 3: Dropout is measured as follows: RSC_ = 1.21 from CS_ to GND. Force 100mA into OUT_ and measure the dropout voltage from OUT_ to CS_. DVDO = (OUT_ - VCS_). 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.
Typical Operating Characteristics
(VIN = 12V, CREG = 1F to GND, IREG = 0, RCS_ = 2 from CS_ to GND, TA = +25C, unless otherwise noted. Typical values are at TA = +25C.)
DROPOUT VOLTAGE vs. TEMPERATURE
MAX16824toc01
CS_ VOLTAGE vs. OUTPUT CURRENT
MAX16824 toc02
OUTPUT CURRENT vs. INPUT VOLTAGE
190 170 OUTPUT CURRENT (mA) 150 130 110 90 70 50 30 10 -10 ILOAD = 100mA ILOAD = 150mA
MAX16824 toc03
1.0 0.9 0.8 DROPOUT VOLTAGE (V) 0.7
0.207 0.202 VCS_ (V) 0.197 0.192 0.187
0.6 0.5 0.4 0.3 0.2 0.1 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C) ILOAD = 100mA
0.182 0 15 30 45 60 75 90 105 120 135 150 OUTPUT CURRENT (mA)
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 VIN (V)
4
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High-Voltage, Three-Channel Linear High-Brightness LED Drivers
Typical Operating Characteristics (continued)
(VIN = 12V, CREG = 1F to GND, IREG = 0, RCS_ = 2 from CS_ to GND, TA = +25C, unless otherwise noted. Typical values are at TA = +25C.)
OUTPUT CURRENT vs. TEMPERATURE
MAX16824toc04
MAX16824/MAX16825
SUPPLY CURRENT vs. TEMPERATURE
MAX16824 toc05
OUTPUT VOLTAGE vs. TEMPERATURE
5.08 5.06 5.04 ILOAD = 0
MAX16824 toc06
200 180 160 OUTPUT CURRENT (mA) 140 120 100 80 60 40 20 0 IOUT = 10mA IOUT = 95mA IOUT = 150mA
3.45 3.25 SUPPLY CURRENT (mA) 3.05 VIN = 28V
5.10
VREG (V)
5.02 5.00 4.98 ILOAD = 4mA
2.85 2.65 2.45
VIN = 6.5V
4.96 4.94 VPWM = VPWM = VPWM = 0 4.92 4.90 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
ILOAD = 1mA
2.25 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
-40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
CS_ VOLTAGE vs. REG OUTPUT CURRENT
0.200 0.199 0.198 0.197 0.196 0.195 0.194 0.193 0.192 0.191 0.190 0.189 0.188 0.187 0.186 0.185 0.184 0.183 0.182 0 1 2 3 4
MAX16824 toc07
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX16824 toc08
LED CURRENT FALL TIME
MAX16824 toc09
5.000 4.995 4.990 VREG (V) IREG = 0
ILED = 150mA VIN = 12V PULSED AT 200Hz (50% DUTY CYCLE)
VPWM_ 2V/div
VCS_ (V)
ILOAD = 100mA
4.985 4.980 4.975 4.970 4.965 4.960 IREG = 4mA IOUT_ 100mA/div 0A 0 4 8 12 16 20 24 28 2s/div IREG = 1mA 0V
ILOAD = 150mA
5
6
7
8
9
10
IREG (mA)
VIN (V)
LED CURRENT RISE TIME
MAX16824 toc10
330Hz DIMMED OPERATION
MAX16824 toc11
VPWM_ 2V/div
ILOAD = 150mA VIN = 12V PWM_ PULSED AT 330Hz (1% DUTY CYCLE)
VPWM_ 2V/div 0V
0V IOUT_ 100mA/div 0A 20s/div
ILED = 150mA VIN = 12V PULSED AT 200Hz (50% DUTY CYCLE) 2s/div
IOUT_ 100mA/div 0A
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5
High-Voltage, Three-Channel Linear High-Brightness LED Drivers MAX16824/MAX16825
Pin Description
PIN MAX16824 1 2 3 4 5, 6, 10, 14 7 8 9 11 12 13 15 16 -- MAX16825 1 2 3 4 5, 14 -- -- -- 11 12 13 15 16 7 NAME OUT1 CS1 IN REG N.C. PWM1 PWM2 PWM3 GND OUT3 CS3 CS2 OUT2 DIN FUNCTION Channel 1 LED Driver Output. OUT1 is an open-drain, constant-current-sinking output rated to 36V. Channel 1 Sense Amplifier Negative Input. Connect a current-sense resistor between CS1 and GND to program the output current level for channel 1. Positive Input Supply. Bypass with a 0.1F (min) capacitor to GND. +5V-Regulated Output. Connect a 1F capacitor from REG to GND. No Connection. Must be left unconnected. Dimming Input 1. PWM1 is a dimming input for channel 1. A logic-low turns off OUT1 and a logic-high turns on OUT1. Dimming Input 2. PWM2 is a dimming input for channel 2. A logic-low turns off OUT2 and a logic-high turns on OUT2. Dimming Input 3. PWM3 is a dimming input for channel 3. A logic-low turns off OUT3 and a logic-high turns on OUT3. Ground Channel 3 LED Driver Output. OUT3 is an open-drain, constant-current-sinking output rated to 36V. Channel 3 Sense Amplifier Negative Input. Connect a current-sense resistor between CS3 and GND to program the output current level for channel 3. Channel 2 Sense Amplifier Negative Input. Connect a current-sense resistor between CS2 and GND to program the output current level for channel 2. Channel 2 LED Driver Output. OUT2 is an open-drain, constant-current-sinking output rated to 36V. Serial-Data Input. Data is loaded into the internal 3-bit shift register on the rising edge of CLK. Latch-Enable Input. Data loaded transparently from the internal shift register to the output latch while LE is high. Data is latched into the output latch on the LE's falling edge and retained while LE is low. Output Enable Input. Drive OE high to place all outputs into a high-impedance mode without altering the contents of the output latches. Drive OE low to force all outputs to follow the state of the output latches. Serial-Data Output. Data is clocked out of the internal 3-bit shift register to DOUT on the rising edge of CLK. DOUT is a replica of the shift register's last bit. Clock Input Exposed Paddle. Connect EP to a large-area ground plane for effective power dissipation. Do not use as the IC ground connection.
--
8
LE
--
9
OE
-- -- --
10 6 --
DOUT CLK EP
6
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High-Voltage, Three-Channel Linear High-Brightness LED Drivers MAX16824/MAX16825
OUT1 IN BANDGAP AND 5V REGULATOR REG CS1 200mV
OUT2
THERMAL SHUTDOWN CS2
OUT3
PWM1 PWM2 PWM3 PWM CONTROL AND LOGIC
CS3
MAX16824
GND
Figure 1. Internal Block Diagram (MAX16824)
Detailed Description
The MAX16824/MAX16825 are three-channel LED drivers that operate from a 6.5V to 28V input voltage range. These devices provide three independent opendrain, constant-current-sinking outputs rated to 36V and deliver up to 150mA of current to each HB LED string. The current in each channel is programmable using an external current-sense resistor in series with each internal power MOSFET's source. The MAX16824 features three separate PWM inputs that allow a wide range of independent dimming level at each of the three outputs. The PWM inputs also function as on/off control inputs for each corresponding output (Figure 1).
The MAX16825 includes a 2Mbps, 4-wire serial interface to control the state of each output (Figure 2). The 4-wire serial interface comprises a 3-bit shift register and a 3-bit transparent latch. The shift register is updated using a clock input CLK and a data input DIN. DOUT is the last bit of the shift register. This feature allows multiple drivers to be cascaded and operated together. The latch is transparent from the shift register outputs to the LED output when LE is high while it latches the shift register state on the falling edge of LE. The output-enable input OE allows simultaneous enabling or disabling of all three outputs.
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7
High-Voltage, Three-Channel Linear High-Brightness LED Drivers MAX16824/MAX16825
OUT1 IN BANDGAP AND 5V REGULATOR REG CS1 200mV
OUT2
THERMAL SHUTDOWN CS2
OUT3
DIN CLK
CS3
DOUT
SHIFT REGISTER
SHIFT REGISTER
SHIFT REGISTER
LE
LATCH
LATCH
LATCH
OE
LOGIC
MAX16825
GND
Figure 2. Internal Block Diagram (MAX16825)
8 _______________________________________________________________________________________
High-Voltage, Three-Channel Linear High-Brightness LED Drivers
On-board pass elements minimize the need for external components while providing 5% LED current accuracy. Additional features include a +5V (5%) regulated output with 4mA output current capability and thermal protection. The MAX16824/MAX16825 use a feedback loop to linearly control the current at each output. The voltage across each sense resistor is regulated to 200mV by the internal feedback loop. The output current is set by selecting the value of RCS. OE is independent of the operation of the serial interface. Data can be shifted into the serial-interface shift register and latched regardless of the state of OE. DOUT is the serial-data output that shifts data out from the MAX16825's 3-bit shift register on the rising edge of CLK. Data at DIN propagates through the shift register and appears at DOUT three clock cycles later.
MAX16824/MAX16825
Applications Information
Programming the LED Current
The MAX16824/MAX16825 use sense resistors to set the output current in each channel. To set the LED current for a particular channel, connect a sense resistor across the corresponding current-sense input (CS_) and GND. For better performance, connect the low side of the current-sense resistors to the IC's ground terminal and the high side to the CS_ terminal with short traces. The value of the sense resistor for a given desired current is calculated with the following equation: RCS _ () = VCS _ (V) IOUT _ (A)
+5V Regulator (REG)
The MAX16824/MAX16825 include a fixed +5V output regulator that delivers up to 4mA of load current for auxiliary low power applications throughout the 6.5V to 28V input voltage range. Connect a 1F compensation capacitor from REG to ground.
Thermal Protection
The MAX16824/MAX16825 enter a thermal shutdown mode in the event of overheating. When the junction temperature exceeds TJ = +165C, the internal thermal protection circuit turns off the series pass elements. The MAX16824/MAX16825 recover from thermal shutdown mode when the junction temperature drops by 23C. The thermal protection does not operate if the regulator (REG) is in a short-circuit condition.
where V CS_ is 200mV and I OUT_ is I LED (see the Electrical Characteristics table).
Input Voltage Considerations
For proper operation, the minimum input voltage must always be: VIN(MIN) VCS _ + VFT(MAX) + VDO where VCS_ is the voltage drop across the sense resistor RCS_, VFT(MAX) is the total forward voltage of all series connected LEDs and V DO is the maximum dropout voltage of the regulator. The minimum operating voltage of the device is 6.5V. If the device is operated below 6.5V, the output current may not meet the full regulation specification (see the Typical Operating Characteristics).
4-Wire Serial Interface (MAX16825)
The MAX16825 features a 4-wire serial interface (DIN, CLK, LE, OE) and a data output (DOUT) that allows the use of a microcontroller to write brightness data to the MAX16825. The serial-interface data word length is 3 bits (D0, D1, D2). The functions of the interface inputs are as follows: DIN is the serial-data input, which must be stable when it is sampled by the MAX16825 on the rising edge of CLK. Data shifts in with the MSB first. This means that data bit D2 is clocked in first, followed by 2 more data bits (D1 and finishing with the LSB D0). CLK is the serial-clock input, which shifts data at DIN into the MAX16825's 3-bit shift register on the rising edge. LE is the latch-enable input that allows the transfer of data from the MAX16825's 3-bit shift register to its 3-bit latch when LE is high (transparent latch) and latches the data on the falling edge of LE (Figure 4). Output enable (OE) provides simultaneous control of the output drivers. Driving OE high places outputs OUT1, OUT2, and OUT3 into a high-impedance mode without altering the contents of the output latches. Driving OE low allows outputs OUT1, OUT2, and OUT3 to follow the state of the output latches.
Pulse-Width Dimming (MAX16824)
The MAX16824 includes pulsed-width current dimming inputs (PWM_) to control the LED brightness. An application of up to 5kHz signal or less is recommended at PWM_ input for proper operation. PWM_ also functions as an active-high enable input for each output channel. A logic-low at PWM_ turns off OUT_ and a logic-high turns on OUT_.
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9
High-Voltage, Three-Channel Linear High-Brightness LED Drivers MAX16824/MAX16825
50% LE tCH tCL tCP tLS 50%
tLW
50% CLK tDH tDS
50%
50%
50%
DIN
50%
DO
50%
D1
D2
tDO
DOUT
50%
DO
tOEW OE 50% 50%
tOEL 80% OUT_ 20% tF
tOEH
tR
Figure 3. 4-Wire Serial-Interface Timing Diagram
Pulse-Width Dimming (MAX16825)
The MAX16825 provides three methods of pulsed-width current dimming. One method of pulse dimming the output channels is to drive OE low while latching a different set of three bits
data. Holding OE low allows the output channels to follow the state of the output latches. The duty cycle depends on LE's frequency. All output channels are affected at the same time.
10
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High-Voltage, Three-Channel Linear High-Brightness LED Drivers MAX16824/MAX16825
50% LE tLRF OUT_ 50%
50% LE tLRR
50% OUT_
50% CLK tCRF OUT_ 50%
50% CLK tCRR
50% OUT_
Figure 4. LE and CLK to OUT_ Timing
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11
High-Voltage, Three-Channel Linear High-Brightness LED Drivers MAX16824/MAX16825
Another method of pulse dimming the outputs is to hold LE high and drive OE with a PWM signal. Because the input bits are always latched, the serial input constantly refreshes the register. The control bits must be carefully selected to dim the outputs properly. A third method is to hold both LE and OE in the enabled state. This allows the data bits to directly control the output channels, and hence, pulse dim the output current. Make sure that the clock frequency does not exceed the maximum rate at which the device can change the state of the output channels. The worst-case power dissipation occurs when the drop across each internal MOSFET is at its maximum with all three channels delivering the maximum allowable output current. The maximum drop across the internal MOSFETs is determined by: VINL - VLED_ - VCS_ when VLED_ is at its minimum. Higher ambient temperature increases the thermal stress even further due to the reduction in voltage drop across the LEDs. The MAX16824/MAX16825 thermal specifications are given according to the JEDEC-51 guidelines. Good mechanical/thermal design practices must be applied to help maintain the device junction temperature below the absolute maximum ratings at all times.
Power Dissipation
The power dissipation (P D ) of the MAX16824/ MAX16825 is determined from the following equation: PD = (VIN x IIN ) + (VINL - VLED1 - VCS1) x (ILED1 x DUTY1) + (VINL - VLED2 - VCS2 ) x (ILED2 x DUTY2) + (VINL - VLED3 - VCS3 ) x (ILED3 x DUTY3) where: VIN = supply voltage VINL = supply Voltage to the LED strings IIN = supply current VLED_ = total forward voltage for one LED string ILED_ = LED current VCS = 200mV drop across RCS_ DUTY = PWM_ duty cycle
Chip Information
PROCESS: BiCMOS-DMOS
12
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High-Voltage, Three-Channel Linear High-Brightness LED Drivers
Pin Configurations
TOP VIEW
OUT1 1 CS1 2 IN 3 + 16 OUT2 15 CS2 14 N.C.
MAX16824/MAX16825
TOP VIEW
OUT1 1 CS1 2 IN 3 + 16 OUT2 15 CS2 14 N.C.
MAX16824
REG 4 N.C. 5 N.C. 6 PWM1 7 PWM2 8 13 CS3 12 OUT3 11 GND 10 N.C. 9 PWM3 REG 4 N.C. 5 CLK 6 DIN 7 LE 8
MAX16825
13 CS3 12 OUT3 11 GND 10 DOUT 9 OE
TSSOP-EP
TSSOP-EP
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13
High-Voltage, Three-Channel Linear High-Brightness LED Drivers MAX16824/MAX16825
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
TSSOP 4.4mm BODY.EPS
AA AA
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
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