NXP Semiconductors AN11524, Примечание к применению

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Application note Rev. 1 — 17 February 2015 36 of 54
NXP Semiconductors
AN11524
NXQ1TXA6 Evaluation Board
8.4 DC-to-DC converter
The same layout techniques implemented in the power stage can be applied to the
DC-to-DC converter as shown in
Figure 24 and Figure 25 . Keep the current loop through
L602 and C609 compact and make sure the decoupling capacitors, inductor and feedback
components are close. Use X7R capacitors of good quality for C605 and C609.
8.5 Current sensing layout technique
When dealing with very low voltages generated across a current sense resistor, use the
“Four-wire” or “Kelvin-connection” technique. It is important to avoid introducing false
voltage drops from adjacent pads and other copper routes.
Fig 24. DC-to-DC converter
Fig 25. PCB layout of DC-to-DC converter in NXQ1TXA6 evaluation board
aaa-015909
VIN BOOT
TP601
SW
FB
COMP
2 1
3
5
6
7
8
4
9
EN
SS
GND
GNDPAD
C606
R605
L602
R607
R608
R606
C605
C608
C609
U601
C607
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