LM566 alternative.

What is your frequency range? ...Jim Thompson

Purely audio band. For audio synth modules.

Looks like the EXAR XR2206 is still available (at Jameco)...

Of course you can make a quite respectable VCO with a 555 Timer and some transistors.

This book...

might be helpful to you. ...Jim Thompson

If you are in the US/Canada and only need a few (10-100) I've got a few tubes of ICL8038's. Which I think is the same as the Exar part JT linked to.

George H.

I'm experimenting with a VCO cluster(aka Cloud) and need a number of basic VCOs. If you're willing to part with a few, I'm interested. I found some on Amazon but many are from China and one doesn't know if they are new or reclaimed. If yours are new in the tube then I'd be interested. I'm in California. E-Mail me if you wouldn't mind selling a few. Thanks

-Kevin

Have you searched for PLLs and only use the VCO part of it ? Unfortunately, the low pin count devices usually have internal connection between the phase detector and VCO, but try to find one without such internal connection.

The VCO of the CD4046 might be a good candidate. It's reasonably linear, though its output is a square wave whose duty cycle isn't that we'll controlled.

cheers

Phil Hobbs

According to the old (1974) Signetics application note, the NE566 VCO is NE565 PLL with th phase detector disabled. The application note also shows how to control the NE565 VCO by injecting the control _current_ into pin 8, effectively bypassing the PD.

Yeah and the 74HC4046 is less good.

George H.

For values of "less good" that are roughly speaking, awful. Very hard to get better than 10:1 ratios, vs 1000:1 with HC4046.

I like the roll-your-own one with a single BJT or MOSFET and 1/2 an LM324. Triangle out from the integrator and square wave output from the comparator. You can shape the triangle wave into a facsimile of a sine wave but that gets more complex or requires trimming.

---sp

I have some experience of the 74HC4046 and it's one device where there is an enormous spread in VCO characteristics amongst manufacturers. In the end I tested a few and settled on what is now NXP.

YMMV

Kevin Glover schrieb:

You might have a look at the LM331 also.

Tilmann

I think I have one or two tubes of Teledyne 9400CJ which are probably equivalent to the Microchip part TC9400. It is a 14 pin IC and good from DC to 100 kHz.

I found this datasheet for the LM566 as parts inventory at msu.edu:

The TC9400:

It's available from Mouser for about $9:

I also might have some Analog Devices AD537, also from Mouser for $67 each (gold plated)!

You might also look at LM331:

and KA331 (Only about $0.50 at Mouser)

email: paul at pstech-inc dot com

Paul

That's sort of the way I'd do it... except I'd use a package of LM339's and make good triangles, and linear frequency versus voltage, with current mirror control.

You can simply add current mirrors to a 555 and attain the same thing more simply... but it's forbidden to even mention a 555 Timer on this newsgroup >:-} ...Jim Thompson

That's complete BS. ;)

I have just seen your message. just thinking. Would it not be possible to use a LM565 's VCO. Would have to design a small board to fit the LM566 socket. If you could find them? also discontinued.

I see i have two unused NE566E's.

Now all you need is a time machine to transport them back to 2016.

RL

Re: Google Groups

Welcome to Usenet (not Google Groups). This group is sci.electronics.design, which is actually older than Google.

It's entirely unmoderated and unrestricted, except for the generally accepted informal rules, known as *netiquette*.

Don't let Rob discourage you--c'mon and join the fun.

Re: NE566

The 566 is a really crappy oscillator. It's perfectly okay for a junkbox project, of course--I've done lots worse things myself--but for a real design there are many, much better choices nowadays.

On the simple end, the oscillator of a CD4046 will work as a very wide-range VCO with a pretty linear tuning characteristic over about

The 4046 has only a square-wave output, so if that's a worry one could use one of many dual op amps. One section would be a Howland current source driving an integration capacitor with its other end grounded, and the other would be a Schmitt trigger controlling the polarity of the Howland. That will be better than the 556, but of course needs a lot of extra resistors. (On a PC board, one could make both the Howland and the Schmitt using one 8x resistor array, so it wouldn't be that many parts in real life.)

Cheers

Phil Hobbs