• TI Thinks Resolved

ISO7841: Using isolator to SPI lines

Part Number: ISO7841

Hi,

I have a little doubt about isolators and SPI lines. I need to communicate with four different ADS1299 sharing the same SPI line and with a baud rate of 15.6 MHz. I saw different texas isolators and the parameters are confusing me. I´m using 3V3 on both sides.

ISO7241M

Signaling Rate => Up to 150 Mbps 

Propagation delay => 16 ns (MAX), 10.8 ns (typical)

Pulse width distortion => 4.2 ns (MAX), typical 0.7 ns

Part-to-part skew => 4.5 ns (MAX)

Output rise/fall time => 0.8 ns (typical)

ISO7841

Signaling Rate => Up to 100 Mbps

Propagation delay => 32 ns (MAX)

Pulse width distortion => 2 ns (MAX), typical 1 ns

Part-to-part skew => 5 ns (MAX), typical 0 ns

Output rise/fall time => 2 ns (typical)

Both fulfill my requirements of isolation. I´d like to know which parameters I need to see in order to have that baud rate for the SPI. Signaling rate of the 7841 is lower than the other, but I think its parameters are better. 

Best regards,

Enio

Quad Channel, 2/2, 150Mbps, Digital Isolator