MAX16825EVKIT+ Maxim Integrated Products, MAX16825EVKIT+ Datasheet - Page 5

• Manufacturer Part Number: MAX16825EVKIT+
• Description: KIT EVAL FOR MAX16825
• Manufacturer: Maxim Integrated Products

Specifications of MAX16825EVKIT+

• Current - Output / Channel: 100mA
• Outputs And Type: 3, Non-Isolated
• Voltage - Output: 26.3V
• Features: Graphic User Interface
• Voltage - Input: 6.5 ~ 28V
• Utilized Ic / Part: MAX16825
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX16825 EV kit demonstrates a high-voltage, 3-
channel, linear high-brightness LED driver using the
MAX16825 IC in a 16-pin TSSOP surface-mount pack-
age. This EV kit is configured to supply an LED current
of 100mA per channel. The MAX16825 IC controls the
LED current by maintaining a 200mV drop across each
external sense resistor (R8, R9, and R10). The EV kit
operates from a 0.5A, 6.5V to 28V rated power supply.
The MAX16825 EV kit uses a standard 4-wire SPI inter-
face for independently controlling each of the three
individual channels. Only the components in the Figure
3 schematic are required when using a user-supplied
SPI interface. The MAX16825 integrates a USB-to-SPI
interface circuit that is based on Maxim’s MAXQ2000
16-bit microcontroller. The EV kit includes Windows
2000/XP/Vista-compatible software that provides a GUI
for exercising the MAX16825 features. The components
on the Figure 4 schematic are only required for PC
evaluation and are not needed for an HB LED design.
The MAX16825 features an exposed paddle that uses
the top-layer and bottom-layer PCB copper as a
heatsink. The exposed paddle connects to GND.
Detailed Description of Hardware
_______________________________________________________________________________________
MAX16825 Evaluation Kit
The MAX16825 EV kit can drive three separate LED
loads. Each LED load can consist of multiple LEDs con-
nected in series. The LED load’s forward voltage can
be up to 26.3V. The EV kit drives LEDs rated for at least
100mA. Proper heat sinking of the LEDs is important for
optimum LED performance and durability.
The current for each MAX16825 EV kit LED channel
(I
three sense resistors (R8, R9, and R10, respectively).
See the equation below to select a different LED current
and a new resistor value. If designing for a higher LED
current, verify that the desired current setting does not
exceed the power rating of the corresponding resistor
(R8, R9, R10) or the LED load. Do not set the LED cur-
rent above 150mA. Use the following equation to cal-
culate the value of the new resistor:
where I
resistor value required to set the desired current of the
LED channel.
LED1
, I
LED_
LED2
is the desired LED current and R_ is the
, and I
LED3
R
_
=
LED Load Configuration
) is configured to 100mA by
Output Current Setting
200
I
LED
mV
_
5