Re: About current mode DAC
It depends on your spec. The differences between two are mainly:
Binary code: Smaller area(no decoder and few switches), worse DNL, same INL.
Thermometer/Unit-element code: More area(needs decoder and much more switches), better DNL, same INL.
As a tradeoff, most people use a mixture of both. MSB bits are in thermometer code, LSB bits are in Binary code.
I read a very good paper about this topic before, it is a reference in Berkeley's EE247 ADC class. Highly recommend!!!