It looks like every chip manufacturer has their own CAN bus TVS product nowadays, e.g. ON Semi NUP2105, Semtech 2492SQ, Bourns T24CAN, Nex PESD2CAN and many others.
Common for all of them are surprisingly high stand-off and breakdown voltages, typically around 24 and 30 V. These seem to be inline with ISO 11898 max bus voltage specification for 24 V systems; way too much for 12 V systems.
Furthermore, most transceivers are designed to work off a 5 V supply and 3.3 V devices becoming more common. There is no way these drivers can put up more than 5 V on the line, and even if we add generous common-mode tolerance it will still be nowhere close to TVS specs.
While doing my research I've stumbled upon this interesting board from TI, demonstrating various ESD protection circuits. All of them use SM712 diodes, designed for RS-485. They have much lower and asymmetrical breakdown specs -7..12 V, which seems to be ideally suited for CAN.
So, my question would be this: why do manufacturers keep churning out those high-voltage devices, and why are devices like the SM712 nowhere to be seen except on those obscure TI boards?
Update:
While most comments and answers are focused on automotive applications and applicable ISO standards, one is standing out. As @Lundin pointed out: "TVS value should be picked after the voltage levels on the electronics you wish to save, no after the expected level of the spikes". This seems to be obvious, but somehow missed by many.
So, I decided to dig in datasheets, and see what is actually out there. On digikey there are 1000+ CAN transceivers, but only of them 300+ are automotive. This seemed promising to support my point. Of course, most of the automotive parts are tolerant to -27V...+40V spikes, some of them going as high as +400V (short pulses).
However non-automotive parts were big surprise. While some (like MAX305x series) do not allow more than 12.5V, a lot of chips can survive 36..40V on a bus (both differential and common mode).
So, I guess both @Lundin's comments taken together do answer my question:There is not much need for lover voltage TVS protection chips because majority of CAN transceivers can tolerate much higher spikes than operational bus voltage.
