LNK562-564

Rev. L 12/21

7

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Thermal Considerations

The copper area underneath the LinkSwitch-LP acts not

only as a single point ground, but also as a heatsink. As

it is connected to the quiet source node, this area should

be maximized for good heat sinking of LinkSwitch-LP.

The same applies to the cathode of the output diode.

Y-Capacitor

The placement of the Y-type cap should be directly from

the primary input filter capacitor positive terminal to the

common/return terminal of the transformer secondary.

Such a placement will route high magnitude common-

mode surge currents away from the LinkSwitch-LP

device. Note: If an input pi (C, L, C) EMI filter is used,

then the inductor in the filter should be placed between

the negative terminals on the input filter capacitors.

Output Diode

For best performance, the area of the loop connecting

the secondary winding, the output diode and the output

filter capacitor should be minimized. In addition, sufficient

copper area should be provided at the anode and

cathode terminals of the diode for heat sinking. A larger

area is preferred at the quiet cathode terminal. A large

anode area can increase high-frequency radiated EMI.

Quick Design Checklist

As with any power supply design, all LinkSwitch-LP

designs should be verified on the bench to make sure

that component specifications are not exceeded under

worst-case conditions. The following minimum set of

tests is strongly recommended:

+

HV DC

INPUT

-

+

Input Filter

Capacitor

-

DC

OUT

PI-4582-061715

Maximize hatched copper

areas (

) for optimum

heat sinking

TOP VIEW

Transformer

D

FB

BP

S

S

S

S

CBP

Output Filter

Capacitor

Figure 7. Recommended Circuit Board Layout for LinkSwitch-LP using D Package (Assumes a HVDC Input Stage).