nx2116 Microsemi Corporation, nx2116 Datasheet - Page 14

• Manufacturer Part Number: nx2116
• Description: Synchronous Pwm Controller With Current Limit, Power Good & Over Voltage
• Manufacturer: Microsemi Corporation

equation
consideration K=1.5 and the current limit is set at 15A,
then
Layout Considerations
frequency switching converters. Layout will affect noise
pickup and can cause a good design to perform with
less than expected results.
connection in the top layer with wide, copper filled ar-
eas. The inductor, output capacitor and the MOSFET
should be close to each other as possible. This helps to
reduce the EMI radiated by the power traces due to the
high switching currents through them. Place input ca-
pacitor directly to the drain of the high-side MOSFET, to
reduce the ESR replace the single input capacitor with
two parallel units. The feedback part of the system should
be kept away from the inductor and other noise sources,
and be placed close to the IC. In multilayer PCB use
one layer as power ground plane and have a control cir-
cuit ground (analog ground), to which all signals are ref-
erenced.
separate loop that does not interfere with the more sen-
sitive analog control function. These two grounds must
be connected together on the PC board layout at a single
point.
Rev. 3.0
03/14/06
R
The over current limit can be set by the following
If MOSFET R
OCP
Choose R
The layout is very important when designing high
Start to place the power components, make all the
The goal is to localize the high current path to a
I
SET
Figure 10 - Over current protection
OCP
comparator
I
SET
I
OCP
K R
K R
I
OCP
OCP
R
DSON
=3.7k
DSON
OCP
DSON
40uA
I
=6.5m , the worst case thermal
OCP
15A 1.5 6.5m
OCP
40uA
R
OCP
vbus
SW
3.656k
NX2116/2116A/2116B/2117/2117A
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