LTC4211
34
4211fc
For more information www.linear.com/LTC4211
APPLICATIONS INFORMATION
In either case, the LTC4211 can be configured to au-
tomatically initiate a start-up sequence. Please refer
to the section on AutoRetry After a Fault for additional
information.
PCB Layout Considerations
For proper operation of the LTC4211’s circuit breaker
function, a 4-wire Kelvin connection to the sense resis
-
tors is highly recommended. A recommended PCB layout
for the sense resistor, the power MOSFET and the GA
TE
drive components around the LTC4211 is illustrated in
Figure22. In hot swap applications where load currents
can reach 10A or more, narrow PCB tracks exhibit more
resistance than wider tracks and operate at more elevated
temperatures. Since the sheet resistance of 1 ounce cop
-
per foil is approximately 0.54mΩ/square, track resistances
add up quickly in high current applications. Thus, to keep
PCB track resistance and temperature rise to a minimum,
PCB track width must be appropriately sized. Consult Ap
-
pendix A of LTC Application Note 69 for details on sizing
and calculating trace resistances as
a function of copper
thickness.
In the majority of applications, it will be necessary to use
plated-through vias to make circuit connections from
component layers to power and ground layers internal
to the PC board. For 1 ounce copper foil plating, a good
starting point is 1A of DC current per via, making sure the
via is properly dimensioned so that solder completely fills
any void. For other plating thicknesses, check with your
PCB fabrication facility.
