LTC3728 Datasheet, PDF (27/32 Pages) Linear Technology – Dual, 550kHz, 2-Phase Synchronous Step-Down Switching Regulator

APPLICATIO S I FOR ATIO
V_IN
R_IN
+
C_IN
SW1
D1
L1
R_{SENSE1 VOUT1}
+
C_OUT1
BOLD LINES INDICATE
HIGH, SWITCHING
CURRENT LINES.
KEEP LINES TO A
MINIMUM LENGTH.
SW2
D2
L2
R_{SENSE2 VOUT2}
+
C_OUT2
LTC3728
R_L1
R_L2
3728 F11
Figure 11. Branch Current Waveforms
signal ground. The R2 and R4 connections should not be
along the high current input feeds from the input
capacitor(s).
4. Are the SENSE ^– and SENSE ⁺ leads routed together
with minimum PC trace spacing? The filter 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 LTC3728 and occupy minimum PC trace area.
3728fb
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