I totally agree with Driver300 comments. Incidentally i was able to handle tssop20 package chips . It is a tric we need to learn and it is simple. we tin the pcb pins. Then apply solder paste , place the chip and position it. Apply heat to the end pins , gripping the chip with a tool on its top. Later we can apply heat ( no more solder) to the pins. Due to surface tension and solder paste conveying heat efficiently, the available solder on the tracks gets bonded to pins of chip. Caution needs to be excercised not to bake the chip. as i told it is skil. I only assume that there are trial chips (dummys) out there to practtice.
the chip can be controlled by the pc 's com port , or parallel port and even usb port. Analog devvices applications notes are exhaustive to explain.
for chip selection, it is always better to go for one with highest frequiency coverage and also fsacility for I and Q signal outputs (quadrature) as in modern times the technology is around IQ modulation or demodulation like software defined radio designs..
a hobbyisyy need not purchase more chips one for each application.
i have exposure to one such application andf am happy with it. thanks to elektor shortwave receiver of dec2006 design, where ADS9851BRSZ is used as DDS.