ltc3827ig-1 Linear Technology Corporation, ltc3827ig-1 Datasheet - Page 25

• Manufacturer Part Number: ltc3827ig-1
• Description: Low Iq, Dual, 2-phase Synchronous Step-down Controller
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
4. Are the SENSE
5. Is the INTV
not be along the high current input feeds from the input
capacitor(s).
with minimum PC trace spacing? The filter capacitor
between SENSE
possible to the IC. Ensure accurate current sensing with
Kelvin connections at the SENSE resistor.
the IC, between the INTV
This capacitor carries the MOSFET drivers current
peaks. An additional 1μF ceramic capacitor placed
immediately next to the INTV
improve noise performance substantially.
R
IN
CC
V
IN
decoupling capacitor connected close to
C
IN
BOLD LINES INDICATE
HIGH SWITCHING
CURRENT. KEEP LINES
TO A MINIMUM LENGTH.
–
+
U
and SENSE
and SENSE
U
CC
and the power ground pins?
CC
+
–
and PGND pins can help
leads routed together
should be as close as
W
Figure 12. Branch Current Waveforms
SW1
SW2
U
D1
D2
6. Keep the switching nodes (SW1, SW2), top gate nodes
7. Use a modified “star ground” technique: a low imped-
L1
L2
(TG1, TG2), and boost nodes (BOOST1, BOOST2) away
from sensitive small-signal nodes, especially from the
opposites channel’s voltage and current sensing feed-
back pins. All of these nodes have very large and fast
moving signals and therefore should be kept on the
“output side” of the LTC3827-1 and occupy minimum
PC trace area.
ance, large copper area central grounding point on the
same side of the PC board as the input and output
capacitors with tie-ins for the bottom of the INTV
decoupling capacitor, the bottom of the voltage feed-
back resistive divider and the SGND pin of the IC.
R
R
SENSE1
SENSE2
C
C
OUT1
OUT2
V
V
OUT1
OUT2
38271 F12
LTC3827-1
R
R
L1
L2
25
38271fd
CC