A flash analog to digital converter on stainless steel foil substrate

In an effort to increase the integration level of large area digital and mixed-signal systems on flexible substrate, we designed and successfully fabricated and characterized a 3-bit flash analog to digital converter on stainless steel foil substrate. High quality laser crystallized polysilicon Thin Film Transistors (TFT) as well as carefully designed comparator circuit made it possible for a high performance flash ADC with maximum sampling rate of 3 Ms/s to be developed on stainless steel foil substrate. Both Integral and Differential Non-Linearity were extracted to be less than or equal to 0.25th of a Least Significant Bit (LSB), which makes it possible to increase the number of bits to 5-bits while keeping the same design structure and operating voltages. The same 3-bit design can also be used along with a 3-bit digital to analog converter in a two-step flash ADC structure to implement a 6-bit converter.