General Description
The MAX16803 current regulator operates from a 6.5V
to 40V input-voltage range and delivers up to a total of
350mA to one or more strings of high-brightness LEDs
(HB LEDs). The output current of the MAX16803 is
adjusted by using an external current-sense resistor in
series with the LEDs. A dimming input allows wide-
range “pulsed” PWM operation. Wave-shaping circuitry
reduces EMI. The differential current-sense input
increases noise immunity. The MAX16803 is well suited
for applications requiring high-voltage input and is able
to withstand automotive load-dump events up to 40V.
An on-board pass element minimizes external compo-
nents while providing ±3.5% output-current accuracy.
Additional features include a 5V regulated output and
short-circuit and thermal protection.
The MAX16803 is available in a thermally enhanced,
5mm x 5mm, 16-pin TQFN package and is specified
over the automotive -40°C to +125°C temperature range.
Applications
Automotive Interior: Map, Courtesy, and Cluster
Lighting
Automotive Exterior: Rear Combination Lights (RCLs)
Emergency Vehicle Warning Lights
Navigation and Marine Indicators
General Lighting
Signage, Gasoline Canopies, Beacons
Features
♦+6.5V to +40V Operating Range
♦Adjustable LED Current (35mA to 350mA)
♦±3.5% LED Current Accuracy
♦High-Voltage DIM Pin for Dimming Interface
♦Integrated Pass Element with Low-Dropout
Voltage (0.5V typ)
♦+5V Regulated Output with 4mA Source
Capability
♦Parallel Operation for LED Current > 350mA
♦Differential LED Current Sense
♦Low Shutdown Supply Current (12µA typ)
♦Low 204mV Current-Sense Reference Reduces
Power Losses
♦Wave-Shaped Edges Reduce Radiated EMI During
PWM Dimming
♦Thermal Shutdown
♦Output Short-Circuit Protection
♦Available in Small, Thermally Enhanced,
5mm x 5mm, 16-Pin TQFN Package
♦-40°C to +125°C Operating Temperature Range
MAX16803
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
________________________________________________________________
Maxim Integrated Products
1
15
16 +
14
13
6
5
7
IN
N.C.
8
OUT
V5
CS+
GND
12
N.C.
4
12 11 9
EN
OUT
N.C.
N.C.
N.C.
N.C.
MAX16803
IN CS-
3
10
DIM
TQFN
TOP VIEW
Pin Configuration
Ordering Information
MAX16803
IN OUT
V5 LEDs
RSENSE
0.1µF
+6.5V TO +40V
+5V REG
CS+
0.1µF
CS-
DIM
PWM DIMMING
GND
EN
Simplified Diagram
19-0532; Rev 1; 4/09
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.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*
EP = Exposed pad.
/V denotes an automotive qualified part.
PART TEMP RANGE PIN-PACKAGE
MAX16803ATE+ -40°C to +125°C 16 TQFN-EP*
MAX16803ATE/V+ -40°C to +125°C 16 TQFN-EP*
EVALUATION KIT
AVAILABLE
MAX16803
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN = VEN = +12V, CV5 = 0.1µF to GND, IV5 = 0, VCS- = 0V, VDIM = +4V, connect RSENSE = 0.58Ωbetween CS+ and CS- (Note 1).
TJ= -40°C to +125°C, unless otherwise noted. Typical values are at TA= +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.
IN, OUT, DIM, and EN to GND ...............................-0.3V to +45V
CS+, CS-, V5 to GND ...............................................-0.3V to +6V
OUT Short Circuited to GND Duration
(at VIN = +16V) ........................................................60 minutes
Maximum Current Into Any Pin (except IN and OUT).........±20mA
Continuous Power Dissipation (TA= +70°C)
16-Pin TQFN (derate 33.3mW/°C above +70°C) ......2666.7mW
Operating Junction 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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage Range VIN (Note 2) 6.5 40.0 V
Ground Current IGILOAD = 350mA 1.4 3 mA
Shutdown Supply Current ISHDN VEN ≤ 0.6V 12 40 µA
Guaranteed Output Current IOUT RSENSE = 0.55Ω350 mA
Output Current Accuracy 35mA < IOUT < 350mA ±3.5 %
IOUT = 350mA (current pulsed),
12V < VIN < 40V 0.5 1.2
Dropout Voltage (Note 3) ∆VDO
IOUT = 350mA (current pulsed),
6.5V < VIN < 12V 0.5 1.5
V
Current rising, DIM rising to 4V 17
Output Current Slew Rate Current falling, DIM falling to 0.6V 17 mA/µs
Short-Circuit Current VOUT = 0V, VIN = 12V 400 600 800 mA
LOGIC INPUT
EN Input Current IEN 100 nA
EN Input Voltage High VIH 2.8 V
EN Input Voltage Low VIL 0.6 V
Turn–On Time tON EN rising edge to 90% of OUT 80 µs
CURRENT SENSE (Note 4)
Regulated RSENSE Voltage VRSNS VSENSE = VCS+ - VCS- 196 203 210 mV
CS- Voltage Range -0.3 +4.1 V
Input Current (CS+) VCS+ = 220mV +14 µA
Input Current (CS-) VCS+ = 220mV -84 µA
DIM Input Current 1µA
DIM Input Voltage High VIH 4V
DIM Input Voltage Low VIL 0.6 V
Turn-On Time tON After DIM rising to 4V (Note 5) 52 µs
Turn-Off Time tOFF After DIM falling to 0.6V (Note 5) 38 µs
MAX16803
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
_______________________________________________________________________________________ 3
Note 1: All devices 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed by design.
Note 2: Resistors were added from OUT to CS+ to aid with the power dissipation during testing.
Note 3: Dropout is measured as follows:
Connect RO= 27Ωfrom OUT to CS+. Connect RSENSE = 0.58Ωfrom CS+ to CS-. Set VIN = +12V (record VOUT as VOUT1).
Reduce VIN until VOUT = 0.97 x VOUT1 (record as VIN2 and VOUT2). ∆VDO = VIN2 - VOUT2.
Note 4: IV5 = 0mA.
Note 5: tON time includes the delay and the rise time needed for IOUT to reach 90% of its final value. tOFF time is the time needed
for IOUT to drop below 10%. See the
Typical Operating Characteristics
. tON and tOFF are tested with 13Ωfrom OUT to CST.
Note 6: Current regulation varies with V5 load (see the
Typical Operating Characteristics
).
Note 7: Thermal shutdown does not function if the output of the 5V reference is shorted to ground.
ELECTRICAL CHARACTERISTICS (continued)
(VIN = VEN = +12V, CV5 = 0.1µF to GND, IV5 = 0, VCS- = 0V, VDIM = +4V, connect RSENSE = 0.58Ωbetween CS+ and CS- (Note 1).
TJ= -40°C to +125°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
THERMAL OVERLOAD
Thermal-Shutdown Temperature +155 °C
Thermal-Shutdown Hysteresis 23 °C
+5V REGULATOR
Output Voltage Regulation V5 (Note 6) 5.0 5.27 5.5 V
V5 Short-Circuit Current V5 = 0V (Note 7) 16 mA
Typical Operating Characteristics
(VIN = VEN = +12V, TA= +25°C, unless otherwise noted.)
OUTPUT CURRENT
vs. TEMPERATURE
MAX16803 toc01
TEMPERATURE (°C)
OUTPUT CURRENT (mA)
1109565 80-10 520 35 50-25
50
100
150
200
250
300
350
400
450
0
-40 125
ILOAD = 350mA
ILOAD = 35mA
ILOAD = 200mA
ILOAD = 100mA
(VCS+ - VCS-) vs. OUTPUT CURRENT
MAX16803 toc02
OUTPUT CURRENT (mA)
(VCS+ - VCS-) (V)
320290230 26080 110 140 170 20050
0.201
0.202
0.203
0.204
0.205
0.206
0.207
0.208
0.209
0.210
0.200
20 350
VIN = 12V
OUTPUT CURRENT
vs. INPUT VOLTAGE
MAX16803 toc03
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
3530510 15 20 25
50
100
150
200
250
300
350
400
0
040
MAX16803
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
4 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VIN = VEN = +12V, TA= +25°C, unless otherwise noted.)
DROPOUT VOLTAGE
vs. TEMPERATURE
MAX16803 toc04
TEMPERATURE (°C)
DROPOUT VOLTAGE (V)
1109565 80-10 5 20 35 50-25
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
-40 125
ILOAD = 350mA
SHUTDOWN CURRENT
vs. TEMPERATURE
MAX16803 toc05
TEMPERATURE (°C)
SHUTDOWN CURRENT (µA)
1109580655035205-10-25
5
10
15
20
25
30
35
0
-40 125
VIN = 40V
VIN = 20V
VIN = 12V
VIN = 6.5V
+5V REGULATOR OUTPUT
vs. TEMPERATURE
MAX16803 toc06
TEMPERATURE (°C)
5V REGULATOR OUTPUT (V)
1109580655035205-10-25
5.1
5.2
5.3
5.4
5.5
5.0
-40 125
ILOAD = 1mA NO LOAD
ILOAD = 5mA
(VCS+ - VCS-) vs. IV5
MAX16803 toc07
IV5 (mA)
(VCS+ - VCS-) (V)
764 52 31
0.199
0.200
0.201
0.202
0.203
0.204
0.205
0.206
0.207
0.208
0.209
0.210
0.198
08
ILOAD = 410mA
+5V REGULATOR OUTPUT vs. VIN
MAX16803 toc08
VIN (V)
5V REGULATOR OUTPUT (V)
353025201510
5.15
5.20
5.25
5.30
5.10
540
LOAD = 1mA
NO LOAD
LOAD = 5mA
200Hz DIMMED OPERATION
MAX16803 toc09
20µs/div
VDIM
2V/div
ILOAD
200mA/div
0A
ILOAD = 350mA
VIN = VEN = 12V
DIM PULSED AT
200Hz (1%
DUTY CYCLE)
0V
200Hz DIMMED OPERATION (EXPANDED)
MAX16803 toc10
20µs/div
VDIM
2V/div
ILOAD
200mA/div
0A
ILOAD = 350mA
VIN = VEN = 12V
DIM PULSED AT
200Hz (50%
DUTY CYCLE) 0V
200Hz DIMMED OPERATION (EXPANDED)
MAX16803 toc11
20µs/div
VDIM
2V/div
ILOAD
200mA/div
0A
ILOAD = 350mA
VIN = VEN = 12V
DIM PULSED AT
200Hz (50%
DUTY CYCLE)
0V
MAX16803
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
_______________________________________________________________________________________ 5
IDIM vs. VDIM
MAX16803 toc13
VDIM (V)
IDIM (µA)
1412108642
50
100
150
200
250
300
0
016
VSNSE vs. VCS-
MAX16803 toc12
VCS- (V)
VSNSE (mV)
4.54.03.53.02.5
201
202
203
204
205
200
2.0 5.0
VIN = 12V
ILOAD = 350mA
Typical Operating Characteristics (continued)
(VIN = VEN = +12V, TA= +25°C, unless otherwise noted.)
Pin Description
PIN NAME FUNCTION
1, 16 OUT Current-Regulated Output. Connect pin 1 to pin 16.
2, 3 IN Positive Input Supply. Bypass IN with a 0.1µF (min) capacitor to GND. Connect pin 2 to pin 3.
4–8, 14 N.C. Not Internally Connected
9 CS+ Positive Input of the Internal Differential Amplifier. Connect the current-sense resistor between CS+
and CS- to program the output current level.
10 CS- Negative Input of the Internal Differential Amplifier. Connect the current-sense resistor between
CS- and CS+ to program the output current level.
11 V5 +5V Regulated Output. Connect a 0.1µF capacitor from V5 to GND.
12 GND Ground
13 DIM Pulsed Dimming Input. Drive DIM low to disable the output. Drive DIM high to enable the output.
Must not be left unconnected.
15 EN Enable Input. Drive EN high to enable the output.
—EP
Exposed Pad. Connect to the ground plane for effective power dissipation. Do not use as the only
ground connection.
MAX16803
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
6 _______________________________________________________________________________________
Functional Diagram
MAX16803
ENABLE
EN REFERENCE
GENERATOR
REGULATOR
IN V5
DIFFERENTIAL
SENSE
AMPLIFIER
THERMAL
SHUTDOWN
DIM
I_REG
IN
OUT
CS+
CS-
Detailed Description
The MAX16803 is a high-current regulator capable of
providing up to a total of 350mA of current to one or
more strings of HB LEDs. A wide operating input volt-
age range of +6.5V to +40V makes the MAX16803
ideal for automotive applications. A +5V regulated out-
put provides up to 4mA of current to power external cir-
cuitry. In addition, the MAX16803 features thermal and
output short-circuit protection. The wide operating volt-
age range helps protect the MAX16803 against large
transients such as those found in load-dump situations
up to 40V.
The MAX16803 uses a feedback loop to control the out-
put current. The differential voltage across the sense
resistor is compared to a fixed reference voltage, and
the error is amplified to serve as the drive to the internal
power series pass device (see the
Functional
Diagram
). The regulation point is factory-set at (VCS+ -
VCS-) = 203mV ±3.5%. The regulated current is user
defined by the value of RSENSE.
The MAX16803 is a current controller internally opti-
mized for driving the impedance range expected from
one or more HB LEDs.
+5V Regulator
The MAX16803 includes a fixed +5V output regulator
that delivers up to 4mA of load current throughout the
+6.5V to +40V input voltage range. Connect a 0.1µF
compensation capacitor from V5 to ground. Shorting
V5 to ground disables the thermal shutdown. When EN
is low, V5 is off. V5 stays on during PWM dimming.
Thermal Protection
The MAX16803 enters a thermal-shutdown mode in the
event of overheating. This typically occurs in overload or
output short-circuit conditions. If the junction tempera-
ture exceeds TJ= +155°C (typ), the internal thermal-pro-
tection circuitry turns off the series pass device. The
MAX16803 recovers from thermal-shutdown mode once
the junction temperature drops by 23°C (typ). The part
therefore protects itself by thermally cycling in the event
of a short-circuit or overload condition.
Applications Information
Programming the LED Current
The MAX16803 uses a sense resistor across CS+ and
CS- to set the LED current. The differential sense ampli-
fier connected across RSENSE provides ground-loop
immunity and low-frequency noise rejection. The LED
current is given by
ILED = VSENSE / RSENSE
MAX16803
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
_______________________________________________________________________________________ 7
Input-Voltage Considerations
For proper operation, the minimum input voltage must
always be:
VIN(MIN) ≥VRSENSE(MAX) + VFT(MAX) + ∆VDO(MAX)
where VFT(MAX) is the total forward voltage of all series
connected LEDs. The minimum operating voltage of the
device is +6.5V. The device operates below +6.5V; how-
ever, output current may not meet the full regulation
specification (see the
Typical Operating Characteristics
).
Low-Frequency PWM Dimming at the Output
The MAX16803 provides pulsed or chopped current
dimming input (DIM). The other method is to connect
DIM to V5 and EN to IN and pulse EN. Both methods
generate a regulated-amplitude PWM current (variable
duty cycle) that can provide control over the LED
brightness (see Figures 1 and 2).
Paralleling Multiple MAX16803s to Drive
One High-Power LED
For applications that require more than 350mA of LED
current, two or more MAX16803s can be paralleled
(see Figure 3). VCS- should not exceed 4.1V.
3
4
2
1
10
9
11
12
56
IN
8
16 15 13
IN
C1
VIN
N.C.
GND
V5
CS-
C2
D1
RSENSE
CS+
MAX16803
7
N.C. N.C. N.C.N.C.
OUT EN DIMN.C.
14
OUT
VDIM
ILED
Figure 1. Dimming with EN Connected to VIN at a Constant
Voltage and DIM Pulsed
3
4
2
1
10
9
11
12
56
IN
8
16 15 13
IN
C1
VIN
N.C.
GND
V5
CS-
C2
D1
RSENSE
CS+
MAX16803
7
N.C. N.C. N.C.N.C.
OUT EN DIMN.C.
14
OUT ILED
Figure 2. Dimming with DIM Connected to V5, EN Connected
to VIN
MAX16803
IN OUT
V5
V5
C1
CS+
C2
R1
CS-
GND
EN
DIM
V5
LEDs
MAX16803
IN OUT
V5
V5
C3
CS+
C4
R2
CS-
GND
EN
DIM
Figure 3. Paralleling MAX16803s
MAX16803
Two Brightness Levels for
TAIL/STOP Lights
Figure 4 shows PWM dimming operation for the
MAX16803 with an ICM7555 timer. The ICM7555 pro-
vides adjustable duty cycle using two external resistors
and a capacitor. In TAIL operation, the output of the
ICM7555 feeds into DIM and lights up the LEDs. The
LED’s brightness depends on the duty cycle of the
ICM7555. When VSTOP is present, DIM is pulled up to
VSTOP. The PWM dimming operation is disabled and
the LEDs light up to full brightness. See the ICM7555
data sheet for formulas to calculate the dimming fre-
quency and the duty cycle.
LED Current Thermal Foldback
With a minimum number of external components, the
MAX16803 provides LED current thermal foldback
using a negative temperature coefficient (NTC) thermis-
tor. Figure 5 shows a thermistor connected to V5 and
the CS+ of the MAX16803. As the temperature increas-
es, the voltage drop across R2 increases causing the
LED current to decrease.
ILED = [VSENSE - [R2 / (R2 + RT)] x V5] / R1
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
8 _______________________________________________________________________________________
IN
EN
DIM
CS-
CS+
OUT
GND
GND
OUT
TRG
DIS
IN
R2
ICM7555
C1
D2
TAIL
STOP
V5
RSENSE
TH
MAX16803
C2
+5V REG
D1
D4
D3
R1
LEDs
R3
C3
Figure 4. PWM Dimming Operation with ICM7555 Timer
IN
EN
DIM
CS-
CS+
OUT
GND
R1
LEDs
C1
VIN
V5
R2
RT
PWM DIMMING
MAX16803
C2
Figure 5. LED Current Thermal Foldback with an NTC Thermistor
Other Applications
The application circuit in Figure 6 implements a two-
level brightness current for TAIL/STOP lights. In TAIL
operation, Q1 is off and the R1 sets the output current.
In STOP operation, Q1 turns on and the output current
is set by a parallel combination of R1 and R2.
Figure 7 shows an application circuit with the
MAX16803 using a single BJT to provide high output
current. For proper operation:
VIN(MIN) > VCESAT(MAX) + VFT(MAX) + VRSENSE
where VCESAT(MAX) is the maximum saturation voltage
of the external BJT.
MAX16803
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
_______________________________________________________________________________________ 9
IN
EN
V5
DIM
CS-
CS+
OUT
GND
R2
C1
TAIL
STOP
V5
R1
MAX16803 C2 LEDs
Q1
Figure 6. Two Brightness Level with Current Level Switch for Tail/Stop Lights
IN
EN
DIM
CS-
CS+
OUT
GND
RSENSE
LEDs
Q1
C1
VIN
V5
PWM DIMMING
MAX16803
C2
Figure 7. Increased LED Current (Amper Range) with a Single BJT
MAX16803
Multichannel HB LED Driver
Figure 8 shows an array of MAX16803s with independent
DIM control. The MAX5094C, a current-mode PWM con-
troller, provides the input power to each LED driver pre-
regulated voltage to multiple MAX16803 drivers.
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
10 ______________________________________________________________________________________
Chip Information
PROCESS: BiCMOS
3
4
2
1
10
9
11
12
56
IN
8
16 15 13
IN
C1
VIN
N.C.
GND
V5
CS-
C2
D1
RSENSE
CS+
MAX16803
7
N.C. N.C. N.C.N.C.
OUT EN DIMN.C.
14
OUT
VDIM
Typical Operating Circuit
REF C3
R3
C6
R4
C4
L1
COMP
FB
CS
GND
VCC
VIN
CT/RT
CT
OUT
MAX5094C
MAX16803
U2
CREF
C2
D1
CCOMP
RCOMP
IN
EN
DIM
R2
CS-
CS+
OUT
GND
V5
R5
C7
LEDs
Q1
C10
MAX16803
U4
IN
EN
DIM
CS-
CS+
OUT
GND
V5
R7
C11
LEDs
C8
MAX16803
U3
IN
EN
DIM
CS-
CS+
OUT
GND
V5
R6
C9
LEDs
Figure 8. Multichannel HB LED Driver for LCD Backlight
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages.
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
16 TQFN-EP T1655-3 21-0140
MAX16803
High-Voltage, 350mA, High-Brightness LED
Driver with PWM Dimming and 5V Regulator
Heaney
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________
11
© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES CHANGED
0 5/06 Initial release —
1 4/09 Updated Ordering Information table and added Package Information table. 1, 10
