Frequency Resolution of max038

Naa, forget that. Why not start with a DDS ?

Rene

Well,we are assigned to use that chip. thank you all the same.

First, it's not hz, it's Hz. Next, 100Hz with 1kHz resolution?

And it is "100 Hz," not "100Hz." :-)

Best,

Ok, IMO, the frequency determining components are resistors, not voltages. Nevertheless, have a look at the datasheet where the slope of Frequency against voltage(resistor) is shown. there take the derivative and do multiply.

Rene

Well,I looked through the datasheet again and found that it is the current at pin IIN that partly determine the frequency. So the current from the output of the DAC,which is connected to the pin IIN,will control the output frequency of MAX038. I think it will be another way to control frequency instead of using resistors,and it will be more easily manipulated by MCU. What is your suggestions? Thanks.

The MAX038 chip has recently been discontinued by Maxim, so you might want to reconsider your choice.

- Michael

Ok. what I wasn't able to figure out was the burden voltage of the IIN current input. So, you supply a current from 2uA to 500uA. This gives you a decade of frequency roughly. Meaning, you have to switch capacitors. You'll need about 3 caps to switch.

Rene

Whether or not a space is left between the number and its units is a matter that's subject to where one is publishing, is it not?

Yeah,I have to use 5 caps controlled by CD4051. I don't know whether it works. Thanks for your suggetions.

Sorry, don't take me seriously.

I do wish they'd re-fab it. Maybe we can initiate a letter-writing campaign. The new version could run from lower voltages and take less power, making it more attractive than the max038. Could help.

Have Jim design one. ;-)

Cheers! Rich

Many classic ic's are being dropped because of ROHC legislation. Distributors are refusing to stock them.

We have a bunch of classics up on our eBay store.

I recall playing with the ICL8038 as a kid, around 1981. The sine waves were visibly off sinusoidal.

I heard the MAX038 was superior but far more expensive.

It costs £15.79 from RS components (~$30?) which about what a 300K FPGA costs.

And if I bought the latter, I'd be able to do a lot more.

What makes the MAX038 worth its price?

I vaguely remember a function generator chip that I used in one of GenRad's portable testers. I added a bunch of chips around it to automate the nulling and distortion reduction. I'll see if I can find the drawing and post it.

...Jim Thompson

That is a good idea. Winfield Hill. Now I have no idea about how to choose a simple chip to replace Max038.

Apparently aren't available any more either. )-; I played with one some years ago, and it was a pretty neat chip. The MAX038 is a sort of replacement for it, right? And now they're gone? )-;.

Thanks, Rich

I found the improved function generator and posted it at...

Newsgroups: alt.binaries.schematics.electronic Subject: Re: Maxim's max038 on the chopping block (S.E.D) Message-ID:

This is a function generator built around an AD630 with add-ons to improve distortion and auto-zero adjustments during use.

Don't ask how it works... this was 20 years ago ;-)

I also ran across the Fan Ripple Killer that I mentioned before and it's attached as FanRippleKiller.pdf

...Jim Thompson