Figure 1: An SOIC form factor chip freshly soldered. Click to enlarge.
In figure 1 is shown an SOIC package style chip (an MCP-3426 ADC converter chip) that I used as part of a recent project. This form factor is relatively easy to solder, but any project requiring the AD9851 series of DDS chips will require the ability to solder even smaller lead widths. The AD9851 has quite a few leads.
So, doing some searching on the net, I found a replacement (although it cannot be used in the same circuit) for the functionality of the AD9851. That newer chip is the Si570, which produces square wave output (as compared to the sine wave output of the AD9851). However, a filter on the square wave output should make the newer chip playable in my scenario, I think.
The Si570 chip has fewer leads to solder, but it seems to have other important benefits that could merit its use in this project.
To be continued …
WB8LZR 