8-bit 5-MS/s Analog-to-Digital Converter for Pixel-Level Integration

A pixel-level 8-bit 5-MS/s Wilkinson-type analog-to-digital converter was designed and fabricated in the IBM 8M1P 130-nm CMOS technology. The pixel blocks are implemented with a core area of 130 μm by 140 μm, consuming about 560 μW at 1.2 V. Taking the measured dynamic range of 0.86 V into account, a signal-to-noise ratio above 65 dB was achieved for small signal amplitudes. The maximum differential and integral nonlinearity remains well below 0.4 LSB and 0.5 LSB, respectively. The conversion time is 160 ns, and the energy per conversion step 470 fJ. The digitizer permits the trimming of gain and offset.