MIC2341 Datasheet, PDF (29/32 Pages) Micrel Semiconductor – Dual-Slot PCI Express Hot-Plug Controller

Micrel, Inc.
wide enough to allow the current to flow while the rise in
temperature for a given copper plate (e.g., 1oz. or 2oz.)
is kept to a maximum of 10°C to 25°C. The return (or
power ground) trace should be the same width as the
positive voltage power traces (input/load) and isolated
from any ground and signal planes so that the
controller’s power is common mode. Also, these traces
should be as short as possible in order to minimize the
IR drops between the input and the load. As indicated in
the Pin Description section, an external connection must
be made that ties together both channel inputs ((+)
Kelvin sense) of each Main power rail (i.e., 3VINA and
3VINB, 12VINA and 12VINB must be externally
connected). These connections should be implemented
directly at the chip. Insure that the voltage drop between
the two (+) Kelvin sense inputs for each rail is no greater
than 0.2mV by using a common power path for the two
inputs (e.g., 12VINA, 12VINB). Finally, the use of
plated-through vias will be necessary to make circuit
connection to the power, ground, and signal planes on
multi-layer PCBs.
MIC2341/2341R
Figure 12. 4-Wire Kelvin Sense Connections for RSENSE
Figure 13. Current Limit Sense Filter for Noisy Systems
October 2007
29
M9999-102507-A
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