The minimum specified creepage and clearance distance across the ISO7021 and ISO7021F digital isolator in the 8-SOIC (D) package is 4.0mm. This is above the 3.0mm minimum requirement of Table 5 of IEC 60079-11:2011 for peak voltage up to 60V for Ex ia level of protection. The CTI is specified to be at least 600V.

Creepage is the shortest path between two conductive parts across the isolation barrier. Creepage is measured along the surface of the insulation. This path is typically found around the end of the package body, as shown in Figure 1-4.

Figure 1-4 Creepage and Clearance Around a Side

Figure 1-5 Clearance Below the Package in a Straight Line

Clearance is the shortest path between conductive leads across the isolation barrier. Clearance is measured through the air. This path can be the same as shown in Figure 1-4 or, if the leads on both sides are in line of sight, a straight line below the package body as shown in Figure 1-5.