Full Nyquist 4-bit ADC operating at half clock rate in InP-HBT technology

Half clock rate 4-bit flash A/D converters have been designed and fabricated in HRL´s InP-HBT-OEIC technology. Two versions of the circuits (with and without on-board divider) have been characterized. The circuits utilize distributed resistor ladder structure to create the quantization reference voltages. Based on signal-to-noise-and-distortion measurements, the typical effective number of bits was calculated to 3.9 bits at 10 GS/S and 4.9 GHz analog input. The two circuit versions (with and without on-board divider) consume about 2.6 and 2.3 A from a single 3.4V supply respectively and allocate a total area of 3675 × 1875 μm².