Logic levels specification syntax
Logic levels specification syntax
(OP)
First, I'm an ME, not an EE, so my question is probably going to seem pretty lame. I have a question about the syntax of a note I found on a number of our specification drawings. The note says,
"Logic levels of digital signals is ±5 VDC."
Now, the "is" confuses me - it seems like it should be "are" for proper english. Secondly, the "±5" has me confused too, since I thought voltages on a logic chip were always positive, with a low voltage for "low" and a high voltage for "high".
Can anybody shed some light on what this note might mean or what it "should" say instead?
Thanks,
Tim
"Logic levels of digital signals is ±5 VDC."
Now, the "is" confuses me - it seems like it should be "are" for proper english. Secondly, the "±5" has me confused too, since I thought voltages on a logic chip were always positive, with a low voltage for "low" and a high voltage for "high".
Can anybody shed some light on what this note might mean or what it "should" say instead?
Thanks,
Tim





RE: Logic levels specification syntax
"It is a worthless ambiguous statement".
In other words, it has no usefulness. Logic is normally single ended positive supply, unless you are using ECL, etc., and typically is +5V. But, I have done +15V logic in very noisy environments. But, I have yet to do ±5V.
I hope this helps.
RE: Logic levels specification syntax
0 - -12VDC = Logic low.