Datasheet

LTC3827-1
25
38271fe
APPLICATIONS INFORMATION
4. Are the SENSE
–
and SENSE
+
leads routed together
with minimum PC trace spacing? The fi lter capacitor
between SENSE
+
and SENSE
–
should be as close as
possible to the IC. Ensure accurate current sensing with
Kelvin connections at the SENSE resistor.
5. Is the INTV
CC
decoupling capacitor connected close to
the IC, between
the INTV
CC
and the power ground pins?
This capacitor carries the MOSFET drivers current peaks.
An additional 1µF ceramic capacitor placed immediately
next to the INTV
CC
and PGND pins can help improve
noise performance substantially.
6. Keep the switching nodes (SW1, SW2), top gate nodes
(TG1, TG2), and boost nodes (BOOST1, BOOST2) away
from sensitive small-signal nodes, especially from
the opposites channel’s voltage and current sensing
feedback pins. All of these nodes have very large and
fast moving signals and therefore should be kept on
the “output side” of the LTC3827 and occupy minimum
PC trace area.
7. Use a modifi ed “star ground” technique: a low imped-
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
CC
decoupling capacitor, the bottom of the voltage feedback
resistive divider and the SGND pin of the IC.
Figure 12. Branch Current Waveforms
R
L1
D1
L1
SW1
R
SENSE1
V
OUT1
C
OUT1
V
IN
C
IN
R
IN
R
L2
D2
BOLD LINES INDICATE
HIGH SWITCHING
CURRENT. KEEP LINES
TO A MINIMUM LENGTH.
L2
SW2
38271 F12
R
SENSE2
V
OUT2
C
OUT2