zevon8
New Member
Hi.. I have a circuit using 2 garden variety oscillators ( 0.1uF from input to ground, 100K feedback, and 1uF and 1M ) that have been used as part of a larger circuit for almost 10 years with no problems. The small variations from one batch to another are not a problem, due to cap tolerances, etc.
What happened the other day was a batch were all oscillating at nearly twice the frequency normal. Both oscilators were doing this. Careful examination and testing could find that the only difference between the previous functional units and the batch running at nearly twice the speed was that the 40106 IC brand used.
The "good" ones used a Fairchild CD40106BCN and the "bad" ones used a Texas CD40106BE. I have used many brands over the years, likely all the big names, and never had this problem before.
The only thing I can figure is there is a different hysterisis window from one brand to the next, intentional or otherwise. Or maybe I happened to get a batch at one extreme of the makers tolerance? The data sheets for both parts don't show anything that I could see to explain the big difference.
Anyone seen anything like this before? Unless I am mistaken, a 40106B is a 40106B, is a 40106B, no ???
Thanks for reading, any insight greatly appreciated!!
What happened the other day was a batch were all oscillating at nearly twice the frequency normal. Both oscilators were doing this. Careful examination and testing could find that the only difference between the previous functional units and the batch running at nearly twice the speed was that the 40106 IC brand used.
The "good" ones used a Fairchild CD40106BCN and the "bad" ones used a Texas CD40106BE. I have used many brands over the years, likely all the big names, and never had this problem before.
The only thing I can figure is there is a different hysterisis window from one brand to the next, intentional or otherwise. Or maybe I happened to get a batch at one extreme of the makers tolerance? The data sheets for both parts don't show anything that I could see to explain the big difference.
Anyone seen anything like this before? Unless I am mistaken, a 40106B is a 40106B, is a 40106B, no ???
Thanks for reading, any insight greatly appreciated!!