The short circuit current is 700uA. If all channels provide this it is 22.4mA. Is this safe?
The current limit for each channel is 700uA. So if an output is shorted you will never get more than 700uA from it. You are correct that if all channels are shorted the total current will be 22.4mA . This will obviously heat up the chip and possibly damage it.
Each output is designed for a 1Mohm minimum load which is 200uA at 200V. There is a foot note on page 4 of the datasheet indicating that the user must be careful that the Tj is not exceeded.
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