Like the other thread about the FLW clock, I missed the fact that this 
driver also has rail-to-rail drive with a high-voltage supply pin (76 
That will clamp any leakage current from the nixie tubes, so a bleeder is 
not needed. ESD structures in the IC are designed to clamp hundreds of 
milliamps (for a brief time), so a few uA will not do any harm.

What was your anode supply voltage when you measured the leakage of your 
nixies ? That will give us an idea how much of a voltage drop your nixie 
has when it's just starting to ionize. My rough guess is your tube will 
have at least 125 volts across it as it just starts to faintly glow. If you 
clamp your driver at 70 volts, you should be able to run your anodes up to 
+195V, which is more than enough. 170 to 180 is typical.

As you alluded to, your actual leakage current thru the driver chip  might 
be far less than the 6uA you measured with your DMM.

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