SC427MLTRT Semtech, SC427MLTRT Datasheet - Page 30

• Manufacturer Part Number: SC427MLTRT
• Description: IC BUCK SYNC ADJ 10A 32MLPQ
• Manufacturer: Semtech
• Series: EcoSpeed™, SmartDrive™r
• Type: Step-Down (Buck)r

Specifications of SC427MLTRT

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.75 ~ 5.25 V
• Current - Output: 10A
• Frequency - Switching: 200kHz ~ 1MHz
• Voltage - Input: 3 ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-MLPQ
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Other names: SC427MLTR

Applications Information (continued)
FB, VOUT, and Other Analog Control Signals
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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.
R
LX with a Kelvin trace to pin 28 on the IC. All of
the LX pins are connected to the LX PAD on the
IC, which should be a sufficient connection and
will prevent the need to connect the resistor
further into the LX plane.
The feedback components for the switcher and
the LDO need to be as close to the FB and FBL
pins of the IC as possible to reduce the possibil-
ity of noise corrupting these analog signals.
ILIM
should be close to the IC and connected to
OUT
power to the
BST, ILIM and LX
Capacitors and Current Loops
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LX and BST are very noisy nodes and must be
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 13).
The connections for the current limit resistor
between the ILIM pin and LX must be as short as
possible and directly connected to pin 28 (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 pin on the IC.
SC417/SC427
30