Part Number: ISO7841
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.
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)
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.
ISO7841 belongs to one of our latest digital isolator families. It is designed to be a part far superior to the ISO7241. From SPI communication point of view, the data rate/rise fall times should be parameters of interest. As you mentioned, both the parts are capable of meeting said requirements for SPI @ 15.6MHz.
I would recommend that the ISO7841 be considered for your application.
In reply to Anand Reghunathan:
I have same question about ISOW7841 3.3V interface.
i designed it with 5v power supply of ISOW7841 then use 3.3V interface voltage level of DSP(example tms320f28335).
ISO7841W The part , i thinks the 3.3v signal is interfaceable. do you have any other advice for circuit?
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