ltc3728legn-trpbf Linear Technology Corporation, ltc3728legn-trpbf Datasheet - Page 30

• Manufacturer Part Number: ltc3728legn-trpbf
• Description: Dual, 550khz, 2-phase Synchronous Step-down Switching Regulator
• Manufacturer: Linear Technology Corporation

APPLICATIONS INFORMATION
LTC3728
ground. The R2 and R4 connections should not be along
the high current input feeds from the input capacitor(s).
4. Are the SENSE
minimum PC trace spacing? The fi lter capacitor between
SENSE
the IC. Ensure accurate current sensing with Kelvin con-
nections at the SENSE resistor.
5. Is the INTV
the IC, between the INTV
This capacitor carries the MOSFET drivers current peaks.
An additional 1μF ceramic capacitor placed immediately
next to the INTV
performance substantially.
30
+
and SENSE
CC
R
IN
CC
decoupling capacitor connected close to
–
V
and PGND pins can help improve noise
IN
and SENSE
C
–
IN
BOLD LINES INDICATE
HIGH, SWITCHING
CURRENT LINES.
KEEP LINES TO A
MINIMUM LENGTH.
should be as close as possible to
+
CC
and the power ground pins?
+
leads routed together with
Figure 11. Branch Current Waveforms
SW1
SW2
D1
D2
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 LTC3728 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
the bottom of the voltage feedback resistive divider and
the SGND pin of the IC.
L1
L2
R
R
SENSE1
SENSE2
C
C
OUT1
OUT2
V
V
+
+
OUT1
OUT2
CC
3728 F11
decoupling capacitor,
R
R
L1
L2
3728fd