OPA828: Improved Howland Current Pump output current with chipped edges

Hi Binit, 

Binit Panda said:

I see the edges are getting chipped off in my output. Any idea on why this could happen?

I see the same behavior in the simulation plot. My opinion is that this may be artificial or dynamic behaviors in the tool (may be in Spice models). I altered the R3 or Rsen values, and found that some square wave output looks fine, especially when current close exceed approx. +/-25mA range. But the OPA828's output Isc is only approx. +/-30mA. All lower output current plots have the "chipped off" plot when it is simulated. It also also looks fine when the input voltage is increased. 

OPA828 Howland Isource 05142025.TSC

The V-I behavior is definitely linear when I performed DC sweep of the input signal from -5Vdc to 5Vdc, and it looks fine as it should in static states. 

If you have other questions, please let me know. 

Best,

Raymond