Need a way to physically disconnect slave devices i2c

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ton88

Joined Nov 10, 2019
17
hello my design needs a way for slave devices to be taken off i2c lines completely iam not sure if just 2 FETs would work or if there is specific IC's designed to work with i2c lines.My biggest concern is when the switch is on and letting i2c signals pass through with high frequencies such as 400khz that i2c uses.
 

Papabravo

Joined Feb 24, 2006
17,316
hello my design needs a way for slave devices to be taken off i2c lines completely iam not sure if just 2 FETs would work or if there is specific IC's designed to work with i2c lines.My biggest concern is when the switch is on and letting i2c signals pass through with high frequencies such as 400khz that i2c uses.
I would use a dual SPST Analog Switch. 400 kHz should be no problem with a low rds(on).
 

Deleted member 115935

Joined Dec 31, 1969
0
Would an I2C chip do for this ?

https://www.ti.com/product/PCA9545A

many on the web sites for muxing and switching I2C bus's.

Also note, you say "physicaly isolate"
all of these and the analog switches are "just" fets,
there is no "physical" isolation,

A reed relay might be the way to go if you want real isolation.

or if its "DC" isolation you require

then plenty of this type around also
https://www.analog.com/en/products/adum1251.html
 
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