ADuM6028-3BRIZ does not work!

Dear colleagues,

I have a problem with the basic operation of ADuM6028-3BRIZ, an isolated DC/DC converter.

The configurations of the ADuM6028 are described below.


I want to get the isolated 3.3V @Pin 6 from the primary voltage input of 3.3V @Pin 3.

The primary voltage (VDDP) of 3.3V, with regard to the Pin 2 and 4, was applied to the Pin 3. 

The Pin 1 (PDIS), was tied to primary ground (Pin 2).

The Pin 8 (VSEL) was tied to the isolated ground (Pin 5 and 7).

Unfortunately, the isolated voltage output @Pin 6 is just around 0.2 V, rather than 3.3V.

I read the datasheet several times, but I do not understand this problem.

Please give me some advice to fix this problem.

Thanks in advance!