On-chip digitally trimmable voltage reference

We present an on-chip digitally trimmable voltage reference which allows the realization of a constant reference voltage with only a maximal deviation of +/- 1.45% of the nominal voltage taking into account all possible process and supply voltage variations, mismatch and a junction temperature range of -40degC - 125degC. The accuracy could be increased even further by using of a more precise external reference signal during trimming and by increasing of the number of switches. The voltage reference was designed and manufactured using a 0.35 mum CMOS process. The digital trimming signals could be stored permanently on-chip after trimming by using of poly fuses in an one-time programmable memory block.