Digital Vs analog

[suveka24]

Dear Admin,

      I need a clarification that using Huntron Access2 prober if it is possible to compare digital and analogue circuits at same signature capturing period. i find difficult on comparing digital IC's using Huntron. while the same board was taken signature for thrice and reference set with Min and Max references also. Most of the pins showing different signatures at each time.

Is the Digital ic's like Ram, ROM, Logic Ic can vary at each time or due to impedance problem its occurring.

[admin]

Hello Suveka,
Usually the differences are caused by "charging effect" where the voltage applied to the circuit will charge capacitors on the PCB and shift the signature on the horizontal axis. Capacitors in the circuit will charge differently from board to board so these differences can occur. Using the Delay or Drain features in the Range tab of the Tree pane may help with capturing repeatable signatures. Maybe you can post an image of a difference on the Forum? This would help with understanding your problem.
Thank you.

Admin (Curtis)