A 10 b 100 Ms/s pipelined subranging BiCMOS ADC

The authors describe a 10-b, 100-Ms/s ADC (analog-to-digital converter) with a pipelined subranging scheme, a sample-and-hold amplifier with 7.6-ns acquisition time, and a 94-dB, 335-MHz op amp, enabling it to operate with 950-mW power dissipation from a single -5 V power supply. The design consists of sample-and-hold amplifiers, a coarse 6-b flash ADC, a fine 5-b flash ADC, a digital-to-analog converter, an analog subtractor, a register, and a digital adder with an error-correction function. The ADC is fabricated using a 0.8- mu m BiCMOS process featuring a double-layer polysilicon capacitor. The signal-to-noise-plus-distortion ratio as a function of input frequency at a 100-Ms/s conversion rate is shown.<>