I was wondering if there is any documentation on the transistor types used in some of the high-speed ADCs. I'm interested in low-temperature operation for research. I'm interested in a large range of ADCs (50 MSPS to multi-GSPS range, 8-16 bit range). CMOS transistors can work at deep cryogenic temperatures while homojunction BJTs' performance reduces dramatically. I've seen some of the very high performance SiGe BiCMOS data converters which are very interesting, but would like to test purely CMOS based ADCs.
Are flash ADCs generally CMOS-based? I've seen the TLC5540 datasheet says it uses a CMOS process. Unfortunately when others mention CMOS it seems they might be talking about CMOS-compatible outputs.
For higher resolutions and speeds, are any of the pipelined DACs CMOS based? This gets more complicated since any internal buffering or amplification in the ADC must also be CMOS. Presumably if most of the ADC uses CMOS technology, then its internal opamps will be CMOS too?
Thanks,
Ian
