A 5V 6b, 80Ms/s BiCMOS Flash ADC

A single 5V, 6-bit Flash A/D converter (ADC) has been developed that supports sampling rates of up to 80 Ms/s. The design of the converter is optimised to operate in under-sampling applications where the ADC has to maintain performance with input frequencies well beyond Nyquist. Excellent dynamic linearity performance has been achieved with input frequencies of up to 75MHz and a gain flatness of better than 0.4dB is obtained over the input signal spectrum of 50MHz-75MHz. This ADC is fabricated on a 1.0¿m advanced BiCMOS process that features trench-isolated bipolar devices with an fT of 10GHz.