Sorry to bump an old thread but this pops up pretty high on the google results for 3394 schematics and has some laughably bad info that needs to be corrected.
No idea why Grumpy_Mike is talking about needing 16 DACs. It states very clearly in the datasheet—quoted in this thread even!—that you can use a single DAC, a multiplexer, and hold capacitors to distribute control voltages to all the different inputs.