Sine wave generator IC

[tcmtech]

Okay this is a simple one but its been so long since I played with basic circuits the simple stuff is getting away from me now.

At one time I used to have a book with a schematic for a simple variable frequency sine wave generator that ran off a fairly common IC, possibly a common op amp, but for the life of me I cant find it or remember what IC number it used.

Anyone got a simple sine wave generator schematic that produces a fairly low distortion sine wave over a range of a few Hz to a few tens of KHz?

 

[mdanh2002]

I recently order 5 samples of the XR2206CP function generator IC (for free) from Exar (www.exar.com/Files/Documents/XR2206_104_020808.pdf). Shipment is very fast, it takes only 5 days by Fed Ex to reach Singapore (and probably 1-2 days within US). The IC is capable of generating sine, triangular, square waves and pulses between 0.01Hz-1MHz.

 

[kinarfi]

Page 5, here's a bunch of circuit I found and kept, enjoy
Kinarfi

 

[tom_pay]

Kinarfi, that is a great document. Some formulas disagree with the ones I have, but they give the same answers, so its good!!

Where did you get it? It's GREAT!!

Tom

 

[Reloadron]

If this was some time back the chip you have in mind might be the Intersil 8038 function generator chip. Which is obsloetre today but was really a pretty slick 14 pin DIP that delivered Sine, Square and Triangular waveforms. Though not a direct replacement there is the Exar 2206 as kinarfi mentions and I believe the Maxim MAX038. The MAX038 function generator chip. If you really want a ICL8038 let me know. I may still have a few buried somewhere.

Ron

 

[tcmtech]

The 8038 sounds right but I am not sure but I think the book was from the 1980's or there abouts.

Thanks for the other ideas though guys!

 

[KMoffett]

Still available:
ICL8038CCPD - $2.50 : OrzParts.com, : Online IC SuperMarket Ship to Worldwide,Great and Transparent price
Precision Waveform Generator/Voltage ICL8038 Precision Waveform Generator/Voltage ICL8038 [IC014] - $5.00 : iStore, Make Innovation Easier
**broken link removed**
https://www.futurlec.com/Harris/ICL8038pr.shtml
**broken link removed**

Ken

 

[Roff]

This might be of interest:
Application Note 263 Sine Wave Generation Techniques

 

[kinarfi]

Here's two more op amp books, open and search for sine, otherwise, just browse, I keep this stuff in my knowledge folder because there is too much to remember, so I store it, Knowledge isn't always knowing it, but knowing where to find it.
**broken link removed**

 

[BrownOut]

This might be of interest:
Application Note 263 Sine Wave Generation Techniques

I've built versions of those logarithimc shaping sine wave generators, and they work wonderfully.

 

[wkrug]

Another possible way ist to use a integrated DDS Chip like the AD9834 from Analog Devices.
It offers Sine, Triangle and Rectangular Waves.
It have a very wide frequency range from 0,3Hz up to 30MHz.
The Output frequency is crystal stabilized.
But the Chip need an Microcontroller with SPI Interface for steering it.

At time we built an function generator with this Chip.

 

[RMMM]

If I remember correctly a bubba oscillator produces very accurate sine waves. You can build it with most quad-pack opamps.

 

[audioguru]

If I remember correctly a bubba oscillator produces very accurate sine waves. You can build it with most quad-pack opamps.

Texas Instruments has an article about sine-wave generators.
Their Bubba oscillator uses four lowpass filters and all need to be changed to change the frequency. It does not have a circuit to limit the output so the first opamp clips a little. The distortion after the first lowpass filter at the Sine Out is pretty bad at 1.1% and at Cosine Out the distortion is 0.1%.
A Phase-shilt oscillator works almost the same and needs "only" 3 filters to be changed to change the frequency. A Wein Bridge oscillator must have a circuit added to limit the level for low distortion and needs only 2 filters to be changed to change the frequency.