Datasheet

28
LTC1628/LTC1628-PG
1628fb
Figure 11. Branch Current Waveforms
APPLICATIO S I FOR ATIO
WUU
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signal ground and a small V
OSENSE
decoupling capacitor
should be as close as possible to the LTC1628 SGND pin.
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. Is the I
TH
pin filter capacitor connected close to the IC,
between I
TH
and the signal ground pins? This capacitor
helps to filter the effects of PCB noise and output voltage
ripple voltage from the compensaton loop
7. 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
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 LINES.
KEEP LINES TO A
MINIMUM LENGTH.
L2
SW2
1628 F11
R
SENSE2
V
OUT2
C
OUT2
+