SC1211STR Semtech, SC1211STR Datasheet - Page 10

• Manufacturer Part Number: SC1211STR
• Manufacturer: Semtech

Specifications of SC1211STR

• Number Of Drivers: 2
• Driver Configuration: Inverting/Non-Inverting
• Driver Type: High and Low Side
• Rise Time: 15ns
• Fall Time: 10ns
• Propagation Delay Time: 37ns
• Frequency (max): 1.5MHz
• Operating Supply Voltage (max): 15V
• Peak Output Current: 3.5A
• Power Dissipation: 2.56W
• Output Resistance: 1.5Ohm
• Operating Supply Voltage (min): 9V
• Operating Supply Voltage (typ): 12V
• Operating Temp Range: 0C to 125C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: SOIC EP
• Lead Free Status / Rohs Status: Not Compliant

Filters for Supply Power
Filters for Supply Power
LA
LA
tor. The capacitor value can be calculated based on the
total gate charge of the top FET, Q
voltage ripple on the capacitor, V
C
Typically, it is recommended to use a 1uF ceramic ca-
pacitor with 25V rating and a commonly available diode
IN4148 for the bootstrap circuit. In addition, a small re-
sistor (one ohm) has to be added in between DRN of the
SC1211 and the Phase Node. The resistor is used to
allievate the stress of the SC1211 from exposing to the
negative spike at the Phase node. A negative spike could
occur at the Phase Node during the top FET turn-off due
to parasitic inductance in the switching loop. The spike
could be minimized with a careful PCB layout. In those
applications with TO-220 package FETs, it is recom-
mended to use a clamping diode on the DRN pin to miti-
gate the impact of the excessive phase node negative
spike.
Filters for Supply Power
Filters for Supply Power
Filters for Supply Power
For VREG pin of the SC1211, it is recommended to use
a 1uF to 4.7uF, 25V rating ceramic capacitor for
decoupling.
LA
LAY Y Y Y Y OUT GUIDELINES
LA
The switching regulator is a high di/dt power circuit. Its
Printed Circuit Board (PCB) layout is critical. A good lay-
out can achieve an optimum circuit performance while
minimized the component stress, resulting in better sys-
tem reliability. For a multi-phase voltage regulator, the
SC1211 driver, FETs, inductor, and supply decoupling
capacitors in each phase have to be considered as a
whole during PCB layout. Refer to Semtech SC2643VX/
SC1211 EVB Layout Guideline.
For the SC1211 driver, the following guidelines are typi-
cally recommended during PCB layout:
1. Place the SC1211 close to the FETs for shortest gate
drive traces and ground return paths.
2. Connect bypass capacitors as close as possible to
decoupling pins (VREG and VIN) and PGND. The trace
length of the decoupling capacitor on VREG pin should
be no more than 0.2” (5mm).
POWER MANAGEMENT
Applications Information (Cont.)
BST
2003 Semtech Corp.
OUT GUIDELINES
OUT GUIDELINES
OUT GUIDELINES
OUT GUIDELINES
> Q
TOP
/ V
BST
BST
TOP
, in one PWM cycle:
, and an allowed
10
3. Locate the components of the bootstrap circuit close
to the SC1211.
SOLDERING CONSIDERA
SOLDERING CONSIDERA
SOLDERING CONSIDERATION
SOLDERING CONSIDERA
SOLDERING CONSIDERA
The exposed die pad of the SC1211 is used for ground
return and thermal release of the driver. The pad must
be soldered to the ground plane that is further connected
to the system ground in the inner layer through multiple
vias. For better electrical and thermal performance, it is
recommended to use all copper available under the driver
as the ground plane, and place the vias as close as pos-
sible to the solder pad. Meanwhile, the vias have to be
masked out to prevent solder leakage during reflow. The
layout arrangement is detailed in the above figure, which
also can be found in the “Land Pattern – Power SOIC-8”
section.
Solder Pad
Vias
TION
TION
TION
TION
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SC1211
Copper
Solder Mask