Combine two 8-bit outputs to make one 16-bit DAC

Inexpensive, 16-bit, monolithic DACs can serve almost all applications. However, some applications require unconventional approaches. This Design Idea design concerns circuitry I recently designed for a tunable-diode laser spectrometer for a Mars-exploration application. The control circuitry included two 16-bit DACs that interface to the radiation-hardened, 8051-variant 69RH051A microcontroller.
Source:http://www.edn.com/article/CA454640.html