USB isolator

[engr_joni_ee]

I have seen a USB isolator ADuM31601 in a schematic. The purpose is to isolate cable power and ground to the rest of the board. I have two questions.

1- When do we need such isolation and why it is necessary
2- What do we have inside the isolator, a transformer ?

 

[FvM]

Why not looking at the datasheet before posting?

 

[KlausST]

Hi,

1) Avoiding ground loops. Reducing leakage current. Increasing safety.

2) ADUMxx comes with a datasheet. It includes pictures as well as textual description. More information than we can give in a forum post. Most detailed, most reliable, most up to date.
If I tell you something about a device ... while it´s datasheet gives different informations --> better trust the datasheet.

Klaus

 

[engr_joni_ee]

I have looked at the datasheet and found in the functional block diagram that there are something look like transformers between GND1 and GND2. Are there transformers in the chip as main components ?

 

[KlausST]

Hi,

Are there transformers in the chip as main components ?

This is a really difficult question to answer.

*****

There is a picture in the datasheet showing transformer.

*****

On the top of the very first page under "GENERAL DESCRIPTION" they say:

The ADuM3160 1 is a USB port isolator based on Analog
Devices, Inc., iCoupler® technology. Combining high speed CMOS
and monolithic air core transformer technology, this isolation
component provides outstanding performance characteristics
and is easily integrated with low and full speed USB-compatible
peripheral devices.

and additionly 4 other times they mention "transformer" in the datasheet...


Hmmmm are there transformers?

How more clear can they be? What proof do you accept?

Klaus

 

[engr_joni_ee]

Just one more question, should we have TVS diodes for ESD protection on the PCB in addition to the USB isolator ? located close to the USB connector.

 

[KlausST]

Just one more question, should we have TVS diodes for ESD protection on the PCB in addition to the USB isolator ? located close to the USB connector.

It depends:
the chip includes ESD protection to a certain specified level.

So you have to ask yourself:
Do you expect the ESD to cross thh specified level:
yes --> install additional ESD protection
no --> no need for additional protection

Please read the additional documents provided by the manufacturer on the product internet pages.

Klaus