10 GSamples/s, 4-bit, 1.2V, design-for-testability ADC and DAC in 0.13µm CMOS technology

This paper demonstrates a 10 GS/s, 4-bit, flash analog-to-digital converter (ADC) and current-steering digital-to-analog converter (DAC) pair for the design of advanced serial-link transceivers. Current mode logic (CML) gates are used to alleviate the severe power bouncing. The active feedback amplifiers, CML, and wave-pipelining technique help achieve the ultimate 10 GHz sampling rate. A design-for-testability circuit using the digital loop-back scheme is added to address the difficulty of at-speed measurements. The experimental results show that the cascaded ADC and DAC pair achieves a 27.3 dBc spurious-free dynamic range and a 25.0 dB signal-to-noise ratio with the 1.11 GHz, -1 dBm stimulus. It corresponds to an ENOB of 3.86 bits. The test chip totally consumes 420 mW from a 1.2 V supply. The areas of the ADC and DAC are 0.1575 mm2 and 0.0636 mm2, respectively in 0.13 mum CMOS technology.