AnsweredAssumed Answered

AB in CD out Headroom Issue?

Question asked by electrojim on Aug 15, 2013
Latest reply on Aug 15, 2013 by ColemanR

I'm running Sigma Studio 3.8 and using the ADAU144x part.  In working with the AB in CD out Condition module, I've run into what looks like a headroom issue.

 

I stand/beg to be corrected here, but based on the 5/23 format of stating levels, I think that Sigma should be able to accommodate a level to about 15 with its 28-bit internal architecture.  I'm using the ABCD module in the 'greater than' mode to compare A and B levels in the 0.1 to 1 level range, and attempting to switch a DC level of 10.  (This is to "hurry along" an integrator during a specific event.)

 

I have a DC Input Entry source set to 10 going into the C input of the block, and am looking at D with both the Real Time Display and a Readback module.  When A goes greater than B, I don't see a 10 coming out.  If I scale down the DC to a 1, then everything seems to work.  Am I violating something here?  This reminds me of smacking against the substrate in a 4066 CMOS switch.

Outcomes