LTC3727-1 Linear Technology, LTC3727-1 Datasheet - Page 27

• Manufacturer Part Number: LTC3727-1
• Description: 2-Phase Synchronous Step-Down Switching Regulators
• Manufacturer: Linear Technology

APPLICATIO S I FOR ATIO
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 LTC3727 and occupy minimum PC trace area.
7. Use a modified “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
R
IN
V
IN
U
C
IN
BOLD LINES INDICATE
HIGH, SWITCHING
CURRENT LINES.
KEEP LINES TO A
MINIMUM LENGTH.
+
U
W
Figure 11. Branch Current Waveforms
SW1
SW2
U
D1
D2
CC
decoupling capacitor, the bottom of the voltage feedback
resistive divider and the SGND pin of the IC.
PC Board Layout Debugging
Start with one controller on at a time. It is helpful to use
a DC-50MHz current probe to monitor the current in the
inductor while testing the circuit. Monitor the output
switching node (SW pin) to synchronize the oscilloscope
to the internal oscillator and probe the actual output
voltage as well. Check for proper performance over the
operating voltage and current range expected in the
L1
L2
R
R
SENSE1
SENSE2
C
C
OUT1
OUT2
LTC3727/LTC3727-1
V
V
+
+
OUT1
OUT2
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3727 F11
R
R
L1
L2
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