SC414MLTRT Semtech, SC414MLTRT Datasheet - Page 27

• Manufacturer Part Number: SC414MLTRT
• Description: IC BUCK SYNC ADJ 6A 28MLPQ
• Manufacturer: Semtech
• Series: SmartDrive™r
• Type: Step-Down (Buck)r

Specifications of SC414MLTRT

• Mfg Application Notes: SC414 Basic Design Procedure
• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 0.75 ~ 5.5 V
• Current - Output: 6A
• Frequency - Switching: 200kHz ~ 1MHz
• Voltage - Input: 3 ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-MLPQ
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Other names: SC414MLTR

Applications Information (continued)
PGND Plane
AGND Island
FB, VOUT, and Other Analog Control Signals
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All other decoupling capacitors must be located
as close as possible to the IC.
PGND requires its own copper plane with no
other signal traces routed on it.
Copper planes, multiple vias, and wide traces are
needed to connect PGND to input capacitors,
output capacitors, and the PGND pins on the IC.
The PGND copper area between the input
capacitors, output capacitors, and PGND pins
must be as small as and as compact as possible
to reduce the area of the PCB that is exposed to
noise due to current fl ow on this node.
Connect PGND to AGND with a short trace or
0Ω resistor. This connection should be as close
to the IC as possible.
AGND should have its own island of copper with
no other signal traces routed on this layer that
connects the AGND pins and pad of the IC to the
analog control components.
All of the components for the analog control cir-
cuitry should be located so that the connections
to AGND are done by wide copper traces or vias
down to AGND.
Connect PGND to AGND with a short trace or 0Ω
resistor. This connection should be as close to
the IC as possible.
The connection from the V
analog control circuitry must be routed from the
output capacitors and located on a quiet layer.
The traces between VOUT and the analog control
circuitry (VOUT, and FB pins) must be short and
routed away from noise sources, such as BST, LX,
VIN, and PGND between the input capacitors,
output capacitors, and the IC.
ILIM and TON nodes must be as short as possible
to ensure the best accuracy in current limit and
on time.
OUT
power to the
BST, ILIM and LX
Capacitors and Current Loops
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LXS with a Kelvin trace to pin 24 on the IC. This
will be a suffi cient connection and will prevent
the need to connect the resistor further into the
LX plane.
The feedback components for the switcher need
to be as close to the FB pin of the IC as possible
to reduce the possibility of noise corrupting
these analog signals.
LX and BST are very noisy nodes and must be
carefully routed to minimized the PCB area that
is exposed to these signals.
The connections for the boost capacitor
between the IC and LX must be short and directly
connected to the LXBST (pin 12).
The connections for the current limit resistor
between the ILIM pin and LX must be as short as
possible and directly connected to pin 24 (LXS).
The LX node between the IC and the inductor
should be wide enough to handle the inductor
current and short enough to eliminate the pos-
sibility of LX noise corrupting other signals.
Multiple vias should be used to provide a good
connection to LX between the IC and the
inductor.
The current loops between the input capacitors,
the IC, the inductor, and the output capacitors
must be as close as possible to each other to
reduce IR drop across the copper.
All bypass and output capacitors must be con-
nected as close as possible to the respective pin
on the IC.
ILIM
should be close to the IC and connected to
SC414/SC424
27