Datasheet

LTC3838
43
3838fa
APPLICATIONS INFORMATION
R
L2
L2
SW1
R
SENSE2
V
OUT2
C
OUT2
V
IN
C
IN
R
IN
R
L1
BOLD LINES INDICATE
HIGH SWITCHING
CURRENT. KEEP LINES
TO A MINIMUM LENGTH.
L1
SW2
3838 F15
R
SENSE1
V
OUT1
C
OUT1
Figure 15. Branch Current Waveforms
• The top N-channel MOSFETs of the two channels have
to be located within a short distance from (preferably
<1cm) each other with a common drain connection at
C
IN
. Do not attempt to split the input decoupling for the
two channels as it can result in a large resonant loop.
• Connect the input capacitor(s), C
IN
, close to the power
MOSFETs. This capacitor provides the MOSFET transient
spike current. Connect the drain of the top MOSFET as
close as possible to the (+) plate of the ceramic portion
of input capacitors C
IN
. Connect the source of the bot-
tom MOSFET as close as possible to the (–) terminal
of the same ceramic C
IN
capacitor(s). These ceramic
capacitor(s) bypass the high di/dt current locally, and
both top and bottom MOSFET should have short PCB
trace lengths to minimize high frequency EMI and
prevent MOSFET voltage stress from inductive ringing.