ISO121: ISO121 layout

Hi Jesse,

It is not recommend to route under the ISO121 as it will reduce the creepage measurement - potentially allowing for arcing depending on the isolation requirements. 

If this is not a concern, routing under the device should be fine. 

Alexander, thanks for your reply, I just route the output +15v/-15v  traces under the device at the output side, is that still have a creepage degradation ? and I put one separated output ground plane on the second layer at output side , and another separated input ground plane on the second layer  at the input side, are these ground plane necessary for the device performance ? thanks !

Hi Jesse,

looks like U2 and U3 are ruining your isolation barrier...

Kai 

Hi Jesse,

I agree with Kai - U2 and U3 are violating the isolation barrier. I believe you need to reconsider your layout. 

U2 is the isolated power supply for ISO121 input side, U3 is the isolated power supply for ISO121 input side. the clearance between the input pins and output pins are more than 3mm, the components also need keep enough body to body clearance ?

Hi Jesse, 

Can you provide the schematic? 

As the layout is drawn it appears that the isolation barrier is being bypassed by U2 and U3. 

Please refer to the attached file.

isolation_amplifier_Schematic.pdf

Hi Jesse,

what maximum voltage is dropping across the isolation barrier?

Kai

1500V

Hi Alexander,

   This small board shall be installed to another board to replace ADI AD210, the GND shall be connected to 0V_IN or 0V_OUT depending on the application. the input/output power regulator are also isolated at rated 3000KV. Do you have any suggestion to avoid the arc you mentioned? thanks !