LTC3410B_15 Datasheet, PDF (12/16 Pages) Linear Technology – 2.25MHz, 300mA Synchronous Step-Down Regulator in SC70

LTC3410B
APPLICATIO S I FOR ATIO
PC Board Layout Checklist
When laying out the printed circuit board, the following
checklist should be used to ensure proper operation of the
LTC3410B. These items are also illustrated graphically in
Figures 4 and 5. Check the following in your layout:
1. The power traces, consisting of the GND trace, the SW
trace and the V_IN trace should be kept short, direct and
wide.
2. Does the V_FB pin connect directly to the feedback
resistors? The resistive divider R1/R2 must be con-
nected between the (+) plate of C_OUT and ground.
3. Does the (+) plate of C_IN connect to V_IN as closely as
possible? This capacitor provides the AC current to the
internal power MOSFETs.
4. Keep the (–) plates of C_IN and C_OUT as close as possible.
5. Keep the switching node, SW, away from the sensitive
V_FB node.
–
V_OUT
+
C_OUT
L1
1
RUN
LTC3410B
2
6
GND V_FB
3
SW
V_IN ⁴
5
C_IN
R2
R1
C_FWD
V_IN
BOLD LINES INDICATE HIGH CURRENT PATHS
3410B F04a
Figure 4a. LTC3410B Layout Diagram
1
RUN
–
V_OUT
+
C_OUT
L1
LTC3410B-1.875
2
GND
6
V_OUT
3 _SW
5
V_IN ⁴
C_IN
V_IN
BOLD LINES INDICATE HIGH CURRENT PATHS ^{3410B F04b}
Figure 4b. LTC3410B-1.875 Layout Diagram
V_OUT
VIA TO V_IN
PIN 1
L1
LTC3410B
SW
VIA TO GND
R1
R2
C_FWD
V_IN
VIA TO V_OUT
C_OUT
C_IN
GND
Figure 5a. LTC3410B Suggested Layout
3410B F05a
V_OUT
V_IN
VIA TO V_IN
PIN 1
L1
LTC3410B-
1.875
SW
C_OUT
C_IN
3410B F05b
Figure 5b. LTC3410B Fixed Output Voltage
Suggested Layout
3410bfa
12