Si8410/20/21
4. Layout Recommendations
Dielectric isolation is a set of specifications produced by safety regulatory agencies from around the world, which
describes the physical construction of electrical equipment that derives power from high-voltage power systems,
such as 100–240 V
systems or industrial power. The dielectric test (or HIPOT test) given in the safety
AC
specifications places a very high voltage between the input power pins of a product and the user circuits and the
user-touchable surfaces of the product. For the IEC relating to products deriving their power from the 220–240 V
power grids, the test voltage is 2500 V (or 3750 V , the peak equivalent voltage).
AC
DC
There are two terms described in the safety specifications:
ꢀ Creepage—the distance along the insulating surface an arc may travel.
ꢀ Clearance—the shortest distance through air that an arc may travel.
Figure 13 illustrates the accepted method of providing the proper creepage distance along the surface. For a
220–240 V application, this distance is 8 mm, and the wide-body SOIC package must be used. There must be no
copper traces within this 8 mm exclusion area, and the surface should have a conformal coating, such as solder
resist. The digital isolator chip must straddle this exclusion area.
Figure 13. Creepage Distance
4.1. Supply Bypass
The Si841x and Si842x families require a 0.1 µF bypass capacitor between V
The capacitor should be placed as close as possible to the package.
and GND1 and V
and GND2.
DD2
DD1
20
Preliminary Rev. 0.1
SILICON [ SILICON ]
