Extreme wide-temperature range 8-bit digital to analog converter in bulk CMOS process

An 8-bit 20k samples-per-second digital-to-analog converter (DAC) capable of operating within the extreme wide-temperature range was developed in a 130nm bulk CMOS technology. Emphasis was placed on the design of a temperature insensitive operational amplifier (op-amp) used in DAC. A novel approach for common mode-feedback with a nested miller compensation op-amp was used in combination with other established methods to mitigate the negative effects of high temperatures on bulk CMOS devices. At 225 °C, the op-amp had a power consumption of 647 μW, with a DC gain of 76 dB, a unity gain bandwidth of 56.8 MHz and a phase margin of 100 degrees. The functionality of the 8-bit DAC was characterized at all operating corners over the extreme wide-temperature range.