[Scullcom] has posted the second part of his function generator build tutorial. [Scullcom] previously posted the first part of this build which covered the XR2206 monolithic function generator IC on which his design is based. In this part [Scullcom] covers the output stages and final assembly.
We’ve covered digital and analog function generator builds before. [Scullcom]’s design complements these well by providing a detailed description of the design he used, and has provided full schematics and code from the Arduino Nano used in this project. The design covers audio frequencies (~40Hz to 30KHz) with square, sine and triangle wave outputs. While the XR2206 can’t compete with modern DDS function generators, if you’re a hacker on a budget and looking for a fun project this may be just the thing for you. And even if you don’t decide to build the one, you might find [Scullcom]’s description of the output stage interesting.
Great project [Scullcom] and we look forward to your next build!
13 thoughts on “Build Your Own Function Generator”
This guy has one of the best educational EE video blogs, certainly worth of following.
According to http://www.exar.com/common/content/productdetails.aspx?id=45 the XR2206 has been discontinued in 2011 already. When looking for the chip farnell returns the AD5932YRUZ saying it’s a replacement part (but i didn’t find 2206 in the datasheet). Mouser and Digikey both says out of stock. The IC is still avaible at Conrad and will be avaible again at Reichelt from 17.08.15, but i suppose they sell some cheap chinese copy (that might fit the specs or not). Where do you buy this chip?
(Sorry for bad english.)
The AD5932 is definitely not a drop-in replacement. It is a SPI programmed part that has sine, square and triangle outputs. So, same basic functions with digital control.
try Jaycar Electronics in Australia
Looks like the XR2206 is obsolete and no longer available as a new part. Too bad, I could use a function generator.
Anyone know of an equivalent chip that’s still for sale?
I’d look into the chip the Tsunami kickstarter used, https://github.com/arachnidlabs/tsunami/blob/master/schematics/schematic.pdf Looks like an AD9838.
There is also very popular AD9850, available as module from China. And there are projects and software libraries to use with it.
You can get both XR2206 and MAX038 (goes up to 20MHz) from eBay and similar sources. Though digital chips are probably easier and more accurate.
MAX038 is a great part, however Maxim stopped manufacturing it about a decade ago, so I’m skeptical of the authenticity of those found on Ebay. Should someone test them please report back!
if you want DDS you can also look at http://www.analog.com/en/products/rf-microwave/direct-digital-synthesis-modulators/ad9833.html
(still waiting that my comment about EOL is accepted by moderation)
max038 can do fine, we can find them.
Jameco claims to have more than 700 in stock for about $8.
Not sure if you are saving money at all looking for obsoleted chips. I also don’t see much of an educated value either.
You’ll learn a lot more going to using opamp and passives to make a function generator. There are also DIY bitbanging DDS using AVR + R2R resistor networks. They are probably the cheapest by far. If you want to be a bit more fancy, you can use a proper DAC and add anti-alias filter, buffer etc.
DDS (AD9950) on a module is about $9 – $12 from Aliexpress. It’ll need a microcontroller + firmware to drive it. There is also the “UDB1002” function generator that has everything all wired up and has LCD, buttons etc. for $30 range.
Please be kind and respectful to help make the comments section excellent. (Comment Policy)