4-bit flash ADC in InP-HBT technology using distributed resistor ladder

4-bit flash A/D converters have been designed and fabricated in InP-HBT technology. The circuit utilizes a novel distributed ladder structure to create the quantization reference voltages. Based on signal-to-noise-and-distortion measurements, the effective number of bits was calculated as 3.9 bits at 10 GS/S. The circuit consumes about 1.9 A from a single 31 V supply and allocates a total area of 3225/spl times/1875 /spl mu/m/sup 2/.