LTC1421 datasheet(34/40 Pages) LINER

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LTC4211

4211fb

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 GATE

drive components around the LTC4211 is illustrated in

Figure 22. 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.

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