NR263S Datasheet, PDF (21/29 Pages) Sanken electric – Light Load High Efficiency Synchronous Buck Regulator IC

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*Please query the product information of the capacitor manufacturer
*Even in the ceramic capacitor, in case of the insertion parts having a lead, its impedance will be higher than
surface-mounted type, therefore please be careful.
*In generally, in case of ceramic capacitors, the allowable ripple current is not included in the specification.
But,because it has the equivalent series resistance ESR inside, the ceramic capacitor occurs slightly heat-generation
by flowing ripple current. Therefore there is a need to comply with the maximum operating temperature containing
the heat generation. In this case, also please consider the heat conduction from the heat generating parts of the
surrounding.
Select the most suitable parts which has a margin in consideration of the use condition, the mounting condition, the
radiation condition, and so on.
8.2 Pattern Design
High current paths in the circuit are marked as bold lines in the circuit diagram below. These paths are required for
wide and short trace as possible. In addition, the pattern trace which is the signal system GND, and the pattern trace
which the main circuit current flows, please to so that it does not become common impedance.
Fig. 8-2 Note points in the wiring pattern
8.2.1 Input / Output Capacitors(C_IN,C_O)
The input capacitor C_IN and the output capacitor C_O are
required to connect to the IC as short as possible.
Think about the image to connect it between the pins of the
IC ideally and directly.
In such cases as the secondary side of the switching power
supply, when there is a filter capacitor on the input side in
advance, though it is possible that it is included with a input
capacitor for NR263S, in case of long distance between filter
capacitor and NR263S , it is necessary to connect as
“line-bypass-capacitor”,aside from the one for the filter.
The ripple current flows to the capacitor of input and output,
you must make Low impedance and ESR.
When you design a circuit board, set to shorter length the
pattern of input and output capacitor.
In the same way,consideration is necessary for route of the
capacitor pattern.
(A)
(B)
(A)･･･Recommended Pattern
(B)･･･No good pattern example
Fig. 8-3 C_IN,C_O
pattern example
NR263S series-DSE Rev.1.0
SANKEN ELECTRIC CO.,LTD
21
2016.03.09
http://www.sanken-ele.co.jp/en/
© SANKEN ELECTRIC CO.,LTD. 2016