DS30911 Rev. 7 - 2 6 of 8
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NMSD200B01
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Application Details
ESD Protected N-MOSFET (DMN601K) and Schottky Barrier
Diode (SD103AWS) integrated as one in NMSD200B01 can be
used as a discrete entity for general applications or part of
circuits to function as a low side switch in a Synchronous
Rectifier. The N-MOSFET is selected based on the input
voltage range as the maximum duty cycles can be greater than
45%. Schottky diode is selected based on instantaneous V
f
(less than 0.75 V) at maximum operation current. The Schottky
diode dissipates very little power because it is on for only a
small portion of the switching cycle. Normally it shows much
lower leakage current and smaller on-resistance (R
DS(ON)
) even
compared to its monolithic counterpart. This device is designed
to improve efficiency and reliability of synchronous buck
converters used in voltage regulator modules (VRM). The
lower V
f
of the Schottky diode leads to lower static loss. Every
time the high side MOSFET is turned on in the buck converter,
the low side Schottky diode is forced to recover the stored
charge and there will be lower loss due to the lower Reverse
Recovery charge of the Schottky diode.
It is designed to replace a discrete N-MOSFET and a Schottky
diode in two separate packages into one small package as
shown in Fig. 17. The Schottky diode parallel to the MOSFET
body diode is faster and has lower voltage drop compared to
the integrated body diode. Overall this device consumes less
board space and also helps to minimize conduction or switching
losses due to parasitic inductances (e.g. PCB traces) in power
supply applications. (Please see Fig. 18 for one example of
typical application circuit used in conjunction with DC-DC
converter as a part of power management system and Fig. 19
for low side DC load control.)
Fig. 17 Example Circuit Diagram
Fig. 18 Synchronous Buck Converter with Integrated Schottky Diode
Typical Application Circuits
High Side
0
Q2
DMN601K
DC-DC Controller
and Driver ICS
D1
SD103AWS
Body Diode
C1
Main Inductor
Low Side
0
VCC
NMSD200B01
Load
Q1
DMN601K
Q1
DMN601K
Gate
Anode
D1
SD103AWS
Drain
Cathode
Source
