In order to realize highly accurate analog to digital conversion for EDTV, HDTV, and video-camera with low power consumption, a monolithic video-rate 8 bit parallel A/D converter has been developed using high-accuracy bipolar transistors with trench isolation. The A/D converter can digitize wide band video signals up to 10 MHz with high signal to nose ratio (45 dB at 10 MHz input) at high conversion rate of 40 MHz. Notwithstanding it contains 7000 bipolar transistors, it consumes only 250 mW and is formed with small chip size (2.73.9mm2).

A distribution of offset voltage of transistor pairs having fine pattern emitter down to 0.5 µm wide required for a parallel A/D converter can digitize at more than 200 MHz were measured. Moreover, contributions of transistor parameters to offset voltage and a realization of the ultra-high speed A/D converter were discussed. As the result, it was shown that the main transistor parameter contributes to the offset voltages is a fluctuation of a current gain, and a contribution of a emitter contact resistance was not so large. And the realization of 6 bit, 1 GHz or 8 bit, 750 MHz A/D converter was obtained.