layout1
Newbie level 2
Hi, I have a discrete time sigma delta. I apply a DC input 100mV away from midscale. The output code (after filter and decimator) is not stable, it changes by a few codes each output. OSR is 364. It looks like noise but results of a tran sim without any tran noise applied. Any ideas what causes this? DC gain of integrators is >80dB, outputs of integrators not saturating. Settling time of switches look OK. Could it be switch charge injection? Thanks.