MAX16807EVKIT+ Maxim Integrated Products, MAX16807EVKIT+ Datasheet - Page 10

• Manufacturer Part Number: MAX16807EVKIT+
• Description: EVAL KIT FOR MAX16807
• Manufacturer: Maxim Integrated Products

Specifications of MAX16807EVKIT+

• Current - Output / Channel: 50mA
• Outputs And Type: 8, Non-Isolated
• Voltage - Output: 32V
• Features: Dimmable
• Voltage - Input: 9 ~ 16V
• Utilized Ic / Part: MAX16807
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5) The gate drive current of the MOSFET is another
6) The drain node of the MOSFET is a switching node.
7) Keep the node area and trace length on the FB pin
8) Connect the power ground plane for the constant-
MAX16807 Evaluation Kit
10
high-frequency switching current to consider. There
are two major loops: one during the MOSFET turn-
on edge and the second during the turn-off edge.
The MOSFET turn-on loop is from the VCC bypass
capacitor positive terminal, through the MOSFET dri-
ver in the device, the gate drive resistor, the MOSFET
gate to source (CGS and CGD), and the current-
sense resistor to the VCC bypass capacitor nega-
tive terminal. There is no direct path for the current
from the current-sense resistor to return to the VCC
bypass capacitor through the ground plane, as the
VCC bypass capacitor is connected to the analog
ground plane and the current-sense resistor is con-
nected to the power ground plane. The best solution
is to connect the analog ground plane to the power
ground plane directly under the MOSFET gate drive
trace. This will ensure that the turn-off current also
has a return path on the ground plane.
Keep this node area small to reduce radiation and
capacitive coupling to other sensitive parts of the
circuit. However, the trace should be wide enough
to carry the large switching currents.
small to reduce any noise pick up.
current LED driver part of the circuit to the boost
converter output filter capacitor negative terminal.
______________________________________________________________________________________
The MAX16807 dissipates power during normal operat-
ing conditions. The heat transferred to the exposed pad
from the die should be properly dissipated to the board
to prevent the device from entering into thermal shut-
down. The exposed pad land area on the top layer
should be of the same size as that of the exposed pad.
Thermal vias are used to carry the heat from the
exposed pad to other layers of the board and spread it
across the board area through copper planes. Thermal
vias should have a maximum 0.4mm hole size and
should be placed at a distance of 1mm from center to
center. For a four-layer board, these vias should be con-
nected to the bottom ground plane and to one internal
ground plane. Do not use thermal relief for the thermal
vias; instead, use solid copper to get the minimum ther-
mal resistance.
Use the following equation to calculate the total power dis-
sipated in the MAX16807 device during normal operation:
where VS is the operating voltage of each of the LED dri-
ver outputs with respect to GND pins, I
current of the MAX16807 including the average of MOS-
FET drive current, and V
dissipate 1W of power, the exposed pad of the device
should be connected to a minimum of 2 square inches
of copper ground plane with 1oz copper thickness.
P
D
=
N
= −
∑
0 7
VS
IN
N
is the input supply voltage. To
×
IOUT I
Power Dissipation
+
B
×
B
V
is the input bias
IN