LTC3374_15 Datasheet, PDF (19/26 Pages) Linear Technology – 8-Channel Parallelable 1A Buck DC/DCs

LTC3374
Applications Information
PCB Considerations
When laying out the printed circuit board, the following
list should be followed to ensure proper operation of the
LTC3374:
1. The exposed pad of the package (Pin 39) should connect
directly to a large ground plane to minimize thermal and
electrical impedance.
2. All the input supply pins should each have a decoupling
capacitor.
3. The connections to the switching regulator input supply
pins and their respective decoupling capacitors should
be kept as short as possible. The GND side of these
capacitors should connect directly to the ground plane
of the part. These capacitors provide the AC current
to the internal power MOSFETs and their drivers. It is
important to minimize inductance from these capacitors
to the V_IN pins of the LTC3374.
4. The switching power traces connecting SW1, SW2, SW3,
SW4, SW5, SW6, SW7, and SW8 to their respective
inductors should be minimized to reduce radiated EMI
and parasitic coupling. Due to the large voltage swing
of the switching nodes, high input impedance sensitive
nodes, such as the feedback nodes, should be kept far
away or shielded from the switching nodes or poor
performance could result.
5. The GND side of the switching regulator output capaci-
tors should connect directly to the thermal ground plane
of the part. Minimize the trace length from the output
capacitor to the inductor(s)/pin(s).
6. In a combined buck regulator application the trace length
of switch nodes to the inductor must be kept equal to
ensure proper operation.
For more information www.linear.com/LTC3374
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