LT3960 :: Multi slave connection

Hi Dejan, 

The LT3960 can support hot plugging as long as there are 120ohm termination resistors next to the LT3960 master and LT3960 slave 1 as shown below. You don't need termination resistors or I2C isolation for LT3960 slave 2 and 3.

Regards, 

Peter Pham

Hello Peter,

thanks for your reply.
So, in connecton you proposed, there is no need to connect grounds of separated together?
According to the picture on the first page of LT3960's datasheet, difference between ground voltages should be less than 25 V (at VCC=3.3 V) or did I miss something?

Many thanks,
Kind regards,
Dejan.

LT9360 ground pins have to be connected like in the datasheet. 

Regards, 

Peter Pham

Hello,

but I really need to have isolated power supply grounds (like shown in schematic in the first post). Should I use I2C isolator like ADuM1251 or equivalent between each LT3960 and sl ave device if a power supply grounds of all LT3960 must be connected together?

Many thanks,
Kind regards,
Dejan.

Hello,

but I really need to have isolated power supply grounds (like shown in schematic in the first post). Should I use I2C isolator like ADuM1251 or equivalent between each LT3960 and sl ave device if a power supply grounds of all LT3960 must be connected together?

Many thanks,
Kind regards,
Dejan.

Hi Dejan,

Please allow me to correct my previous statement. 

It is not necessary to connect the GND of the master and slave LT3960 together as long as the common-mode range of I2CAN busses doesn’t exceed the limit for the provided supply voltage (+/-25V for 3.3V VCC, +/-36V for 5V VCC).

Regards, 

Peter Pham