LTC3545 LINER [Linear Technology], LTC3545 Datasheet - Page 16

• Manufacturer Part Number: LTC3545
• Description: Triple 800mA Synchronous Step-Down Regulator-2.25MHz
• Manufacturer: LINER [Linear Technology]

LTC3545/LTC3545-1
APPLICATIONS INFORMATION
PC Board Layout Checklist
When laying out the printed circuit board, the following
checklist should be used to ensure proper operation of
the LTC3545/LTC3545-1. These items are also illustrated
graphically in Figures 3 and 4. Figure 3 shows the power
path components and traces. In this fi gure the feedback
networks are not shown since they reside on the bottom
side of the board. Check the following in your layout:
1. The power traces consisting of the PGND trace, the SW
2. Does each of the V
16
respective feedback resistors? The resistive dividers
must be connected between the (+) plate of the cor-
trace, the PV
be kept short direct and wide.
IN
(VIA TO FEEDBACK
trace, the V
NETWORK)
FBx
pins connect directly to the
IN
C2
GNDA
V
and GNDA traces, should
V
IN
OUT1
C5
L1
SW1
Figure 3. Layout Diagram
SW3
SW2
3. Keep C1 and C5 as close to the part as possible.
4. Keep the switching nodes (SWx) away from the sensi-
5. Keep the ground connected plates of the input and
6. Care should be taken to provide enough space between
responding output fi lter capacitor (e.g. C2) and GNDA.
If the circuit being powered is at such a distance from
the part where voltage drops along circuit traces are
large, consider a Kelvin connection from the powered
circuit back to the resistive dividers.
tive V
output capacitors as close as possible.
unshielded inductors in order to minimize any trans-
former coupling.
C1
L3
L2
FBx
PV
IN
nodes.
C4
C3
PGND
V
V
OUT3
OUT2
3545 F03
(VIA TO FEEDBACK
NETWORK)
(VIA TO FEEDBACK
NETWORK)
35451fb