General Description
The MAX16803 evaluation kit (EV kit) demonstrates a
current-controlled, high-output-current LED driver
based on the MAX16803 current regulator. The EV kit is
capable of supplying regulated output currents of up to
350mA, can run at supply voltages between 6.5V and
40V, and can operate at temperatures ranging from
-40°C to +125°C.
The MAX16803 EV kit features a PWM dimming control,
user-selectable three-level output current setting, and a
5V-regulated output, which can supply up to 4mA of out-
put current. The MAX16803 EV kit is a fully assembled
and tested board.
Features
o6.5V to 40V Supply Voltage Range
oSelectable 150mA, 250mA, or 350mA Output
Current
o5V-Regulated Output
oPWM Dimming Control
oPackage Dissipates Up to 2.666W at TA= +70°C
oLead-Free and RoHS compliant
oFully Assembled and Tested
Evaluates: MAX16803
MAX16803 Evaluation Kit
________________________________________________________________
Maxim Integrated Products
1
19-0634; Rev 1; 11/08
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.
PART TYPE
MAX16803EVKIT+ EV Kit
SUPPLIER PHONE WEBSITE
KEMET Corp. 864-963-6300 www.kemet.com
Murata Electronics North America, Inc. 770-436-1300 www.murata-northamerica.com
Susumu International USA 208-328-0307 www.susumu-usa.com
TDK Corp. 847-803-6100 www.component.tdk.com
Component Suppliers
Ordering Information
+
Denotes lead-free and RoHS compliant.
Note: Indicate that you are using the MAX16803 when contacting these component suppliers.
DESIGNATION QTY
DESCRIPTION
C1 1
0.1µF, 50V X7R ceramic capacitor
(0603)
Murata GRM188R71H104KA93D or
TDK C1608X7R1H104K
C2 1
0.1µF, 10V X7R ceramic capacitor
(0402)
Murata GRM155R71C104KA88D or
KEMET C0402C104K8RACTU
J1, J2 2 0.1in, 3-pin headers (through hole)
J3, PWM_IN,
RSNS, VIN, V5
5 0.1in, 2-pin headers (through hole)
LED+, LED- 2 0.1in, 1-pin headers (through hole)
R1 1 0.56Ω ±1%, 1/4W resistor (0805)
Susumu RP2012T-R56-F
R2 1 0.82Ω ±1%, 1/4W resistor (0805)
Susumu RP2012T-R82-F
U1 1
High-output-current LED driver
(16 TQFN-EP*)
Maxim MAX16803ATE+
— 1 PCB: MAX16803 Evaluation Kit+
Component List
Figure 1. MAX16803 EV Kit Board
*
EP = Exposed pad.
Evaluates: MAX16803
MAX16803 Evaluation Kit
2 _______________________________________________________________________________________
Quick Start
Recommended Equipment
Before beginning, the following equipment is needed:
• 0 to 30V or above, 0.5A DC power supply
Procedure
The MAX16803 EV kit is fully assembled and tested.
Follow these steps to verify operation. Caution: Do not
turn on the power supply until all connections are
completed.
1) Connect a DC power supply (0 to 30V or above,
0.5A) to VIN.
2) Place jumper J1 between pins 1-2 to enable U1.
3) Close jumper J3.
4) Open all pins of jumper J2 to select 150mA output
current.
5) Connect a 350mA-rated LED between LED+ and
LED-.
6) Turn on the power supply and increase the input
voltage above 6.5V. The LED glows with full bright-
ness. Measure the LED current, and it shows
150mA ±3.5%.
7) Increase the supply voltage to 16V and the LED
current will be stable. Measure the LED current and
it shows 150mA ±3.5%. Measure voltage across
V5, and it shows 5.27V ±5%.
9
10
11
12
CS+
N.C.N.C.N.C.N.C.
DIMN.C.EN
J1
OUT
8765
13141516
CS-
V5
GND
N.C.
IN
C1
0.1μF
IN
OUT
4
3
2
1
1
2
3
13
1
2
VIN
MAX16803
U1
C2
0.1μFR2
0.82Ω
1%
R1
0.56Ω
1%
1
2
V5
1
2
J3
1
2
RSNS
1
2
LED
LED+
LED-
J2
1
2
PWM_IN
2
Figure 2. MAX16803 EV Kit Schematic
Detailed Description of Hardware
The MAX16803 EV kit demonstrates a high-output-cur-
rent LED driver with accurate current control based on
the MAX16803 current regulator. This EV kit is capable
of supplying regulated output currents of up to 350mA
and can run at supply voltages between 6.5V and 40V.
If the supply voltage is above the LED operating volt-
age by more than 7.5V, then the maximum output cur-
rent should be limited to prevent the device from
entering into thermal shutdown due to excessive power
dissipation.
The MAX16803 EV kit features PWM dimming to control
the LED brightness by varying the duty cycle of the
PWM input signal. Users can select between three lev-
els of output LED currents by setting jumper J3 (see
Table 1 for jumper settings). The MAX16803 EV kit also
includes a connection for the 5V-regulated output and
access to the on-board current-sense resistor.
Output Current Setting
The output current can be set to 150mA, 250mA, or
350mA by adjusting the position of jumper J3 (see
Table 1 for jumper settings). The current-sense resistor
is accessible through the RSNS connector. The output
current can be adjusted by removing R2 or R3, open-
ing all the pins of J3, and then connecting a resistor
across RSNS with a value calculated using the follow-
ing equation:
where RSNS is the external current-sense resistor and
IOUT is the desired output current.
PWM Dimming
The PWM dimming is for controlling the LED brightness
by adjusting the duty cycle of the PWM input signal
connected to the PWM_IN input. A HIGH at PWM_IN
input turns on the output current and a LOW turns off
the output current. Connect a signal with peak ampli-
tude between 5V and 40V and with frequency between
100Hz and 2kHz and vary the duty cycle to adjust the
LED brightness. LED brightness increases when duty
cycle increases and vice versa. Duty cycle can be as
low as 10% even at a PWM frequency of 2kHz.
Power Dissipation
Thermal shutdown turns the device off if power dissipa-
tion in the IC causes the junction temperature to reach
+155°C (typ). An external resistor can be added at the
input to the device or in series with LED to reduce the
power dissipation in the IC. The resistor’s power rating
should be higher than I2R. (I is the input current or LED
current, and R is the value of the added resistor.)
Use the following equation to calculate the maximum
LED current that can be drawn from the device without
causing a thermal shutdown:
where 2.666W is the maximum power dissipation
capacity of the device when mounted on a board as
per JEDEC specifications with ambient temperature
below +70°C. VIN is the input supply voltage and VLED
is the operating voltage of the LED.
5V-Regulated Output
The +5V regulator can be used to power other compo-
nents from the V5 connector. The 5V output can supply
up to 4mA of current and is not disabled during PWM off.
Jumper Selection
Three-pin jumper J1 controls the EN pin of the
MAX16803 and can enable or disable the device.
Three-pin jumper J2 can select between three different
output current settings. Two-pin jumper J3 controls the
PWM input of the device. Close J3 to disable PWM dim-
ming. Table 1 lists the jumper options.
IVV
LEDMAX IN LED
.
=−
2 666
RI
SNS OUT
.
=0 203
Evaluates: MAX16803
MAX16803 Evaluation Kit
_______________________________________________________________________________________ 3
SHUNT POSITION AND FUNCTION
JUMPER 1-2 2-3 Open
J2 U1 enabled U1 disabled —
J2 350mA 250mA 150mA
J3 Closed: PWM disabled
Open: PWM enabled
Table 1. Jumper J1, J2, and J3 Functions
Evaluates: MAX16803
MAX16803 Evaluation Kit
4 _______________________________________________________________________________________
Figure 5. MAX16803 EV Kit PCB Layout—Solder Side
Figure 3. MAX16803 EV Kit Component Placement Guide—
Component Side
Figure 4. MAX16803 EV Kit PCB Layout—Component Side
Evaluates: MAX16803
MAX16803 Evaluation Kit
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 _____________________
5
© 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 8/06 Initial release —
1 11/08 Removed LED from EV kit. 1
Revision History
