Re: [uCsimm] Are the uCsimm I/O pins 5V Tolerant?

From: John Ananny (
Date: Thu Feb 03 2000 - 20:14:35 EST

> I would stay away from LS as when a device is new it can be 'healthy'
> enough to go to 4.2 volts VoH.

Very true.

Obviously, data sheets trump hand-waving :-), but in my experience, an
LS-series VoH above 4V is seen only with an unloaded output. As soon as
you draw any appreciable current from the output stage (by hooking it up to
an input on the EZ, say) you end up seeing something in the neighbourhood
of 3.5V, so it's still a safe workaround. But adding the resistor stack
you describe is safer yet...


John Ananny
Interval Research Corporation (650) 842-6039
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