Just Another LPT DAC

[charlysan]

Hello! Although numerous LPT DAC designs exist, I was inspired to create a new one similar to a model I owned 30 years ago. By taking ideas from various projects, I have shaped this design to closely resemble the format of the original, which I regrettably lost. KiCad and gerber files can be downloaded from this repository. You can also check the Wiki for some real pictures and videos.

Cheers

 

[Chuck(G)]

Yup, the old R-2R ladder design. The problem with these when made with discretes is that they're not very accurate. If you can spare a Vcc source, even a veneered and generated DAC0808 will be far superior. Even if you use 1% tolerance resistors, the result won't be good enough for more than about 5.5 bits. Of course, you should follow your ladder with an op-amp stage to avoid loading it down.

Nice layout, though!

 

[charlysan]

Yup, the old R-2R ladder design. The problem with these when made with discretes is that they're not very accurate. If you can spare a Vcc source, even a veneered and generated DAC0808 will be far superior. Even if you use 1% tolerance resistors, the result won't be good enough for more than about 5.5 bits. Of course, you should follow your ladder with an op-amp stage to avoid loading it down.

Nice layout, though!

Yes, I know. The goal here was not to get best DAC accuracy, but rather re-create an old R-2R design.