LTC3613
28
3613fa
APPLICATIONS INFORMATION
• Place the BOOST, PV
IN
, SW, and PGND pins facing the
power train components. Keep high dV/dt signals on
BOOST and SW away from sensitive small-signal traces
and components.
•
For R
SENSE
current sensing, place the sense resistor
close to the inductor on the output side. Use a Kelvin
(4-wire) connection across the sense resistor and
route the traces together as a differential pair. RC filter
the differential sense signal close to SENSE
+
/SENSE
–
pins, placing the filter capacitor as close as possible
to the pins. For DCR sensing, Kelvin connect across
the inductor and place the DCR sensing resistor closer
to the SW node and further away from the SENSE
+
/
SENSE
–
pins. Place the DCR capacitor close to the
SENSE
+
/SENSE
–
pins.
• Place the resistive feedback divider R
FB1/2
as close as
possible to V
OSNS
+
/V
OSNS
–
pins and route the remote
output and ground traces together as a differential
pair and terminate as close to the regulation point as
possible (preferably Kelvin connect across the capacitor
at the remote output point).
• Place the ceramic C
VCC
capacitor as close as possible to
the INTV
CC
and PGND pins. Likewise, the C
B
capacitor
should be as close as possible to BOOST and SW pins.
These capacitors provide the gate charging currents for
the onboard power MOSFETs.
• Place small-signal components as close to their respec-
tive pins as possible. This minimizes the possibility of
PCB noise coupling into these pins. Give priority to
V
OSNS
+
/V
OSNS
–
,
SENSE
+
/SENSE
–
, ITH, RT and V
RNG
pins. Use sufficient isolation when routing a clock signal
into MODE/PLLIN pin so that the clock does not couple
into sensitive small-signal pins.
• Filter the SV
IN
input to the LTC3613 with a simple RC
filter close to the pin. The RC filter should be referenced
to signal ground.
