NJW4800
ꢀAPPLICATION TIPS
In the application that does a high-speed switching of NJW4800, because the current flow corresponds to the input
frequency, the substrate (PCB) layout becomes an important.
NJW4800 is driving the High-side/Low-side SW gate with high speed to reduce switching losses. The transient voltage
is generated by parasitic inductance and a high-speed current change of high side and low side SW.
You should attempt the transition voltage decrease by making a current loop area minimize as much as possible.
Therefore, you should make a current flowing line thick and short as much as possible.
You should insert a bypass capacitor between VDD terminal and GND terminal to prevent malfunction by generating
over voltage and/or exceed maximum input voltage rating. The recommended bypass capacitor is 1µF or more high
frequency capacitor.
A 100µF aluminum electrolysis capacitor is recommended for smoothing condenser. However, you should use larger
capacitor by sufficient evaluation (assessment) due to load condition and/or application use environment. (There is a
possibility that the supply voltage rises by inductive kickback when the supply current of the inductive load is large.)
The bypass capacitors should be connected as much as possible near VDD terminal.
Ex. Bill of Materials
Components
CIN
Parts Name
－
Functions
Aluminum-Cap.
Manufacturers
Nippon Chemi-con
CP
CREG
CBS
GRM21BB11H104KA01B
GRM31MB31H105KA87B
GRM21BR71H474KA88B
RK73B1JT473
Murata
Murata
Murata
KOA
Ceramic-Cap. 0.1µF, 50V (B-val)
Ceramic-Cap. 1µF, 50V (B-val)
Ceramic-Cap. 0.1µF, 50V (X7R-val)
47kΩ
RFLT
Ver.2010-09-29
- 15 -
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