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The TVS leakage current is given in datasheets as Irm at Vrm.
Two related questions about TVS specifications:
How will the leakage current change if the voltage is less than Vrm (e.g. half)? Will it drop dramatically or is a more linear drop to be expected?
How common it is for leakage current to reach the "maximum" as opposed to the "typical" value in real life? They seem to be orders of magnitude different.
Current near breakdown generally goes exponentially with voltage. Note this is breakdown current only, and total current includes saturation current (normal reverse-bias current of the junction, which has a sort-of-inverse-exponential curve instead).
Note also, it is significantly worse for very low voltages, where zener effect dominates. This is basically why 3.3V TVS don't exist: they don't perform any better than 5V parts anyway.
So, depending on where the datasheet measures it, maybe a lot less, maybe not much. This is not useful for design purposes, and if you need low leakage, consider another method (perhaps a smaller zener, boosted by a BJT or MOSFET; or a more active circuit, the response time of which may suffer, needing to be taken up with relatively large capacitance as well).
This brief list of 10 TVS design guidelines should be useful.
MDE Semiconductor - Typical TVS design aids
Especially note the first one:
So if typical leakage is specified at ambient temperature of say 20 degrees C, and max operating temperature is say 120 degrees C, the leakage current at Tmax could be expected to increase over Itypical by a factor of
2^((120-20)/15)
or about a factor of 64 for a doubling temperature of 15 degrees
and by a factor of about 1000 for a doubling temperature of 10 degrees C (!!!)
TVS's have two current specifications - one is a specified current as the device starts to enter the rapid breakdown region and is more about the voltage that causes this current to flow.
The other is the typical leakage current when Vapplied is substantially less than Vbreakdown. You'd hope that these would be very substantially different in magnitude, and they are.
https://mdesemiconductor.com/typical-tvs-design-aids/
This TI application note How to select a surge diode may address the questions you are intending to ask.
They provide typical current with voltage curves and the explanation of Vbr and Vrwm may answer your query about typical amd maximum valuesof standoff current.
From the above link:
This Toshiba application note also looks useful. Basics of ESD Protection (TVS) Diodes
Page 14 shows a graph of leakage well below breakdown versus breakdown currents.
This 1 page Protek document Understanding TVS clamping also covers what you are asking but may need to be looked at carefully to extract the information.
Related :
Littlefuse - see Technical Resources tab.
Easybom - some value.
Selecting TVS's - some value.
To complete the answers above: The typical leakage current of a TVS diode is much lower than the maximum specified. this is due to the guardband taken by semiconductor makers. For example for STM SMAJ devices, they specified 0.2 µA for 10 V TVS and if you look the figure 9 in the datasheet the typical value is 0.2 nA. So a factor 1000.
It is very unlikely that you will get a device with a leakage current reaching the maximum specified value in the datasheet.
The leakage current is not varying much if you keep far from the avalanche (the VBR).
Cheers
