Frequency Resolution of max038

[JLU_EE]

I wonder if I wanna design a function generator of 100hz to 10Mhz with
1khz resolution,how to select DAC.
How about 10 bit DAC.
Another question, I noticed that Max038 can be used as FSK Generator in
the datasheet,how to achieve this function via MCU.
Thanks

 

[Rene Tschaggelar]

I wonder if I wanna design a function generator of 100hz to 10Mhz with
1khz resolution,how to select DAC.
How about 10 bit DAC.
Another question, I noticed that Max038 can be used as FSK Generator in
the datasheet,how to achieve this function via MCU.

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

Rene

 

[JLU_EE]

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

 

[Winfield Hill]

JLU_EE wrote...

I wonder if I wanna design a function generator of 100hz to 10Mhz
with 1khz resolution,how to select DAC.

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

 

[Mochuelo]

JLU_EE wrote...

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

And it is "100 Hz," not "100Hz."
http://physics.nist.gov/cuu/Units/checklist.html, #15.

Best,

 

[Rene Tschaggelar]

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

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

 

[JLU_EE]

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.

 

[Michael Kissin]

I wonder if I wanna design a function generator of 100hz to 10Mhz with
1khz resolution,how to select DAC.
How about 10 bit DAC.
Another question, I noticed that Max038 can be used as FSK Generator in
the datasheet,how to achieve this function via MCU.
Thanks

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

http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1257

- Michael

 

[Rene Tschaggelar]

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.

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

 

[Winfield Hill]

Mochuelo wrote...

And it is "100 Hz," not "100Hz."
http://physics.nist.gov/cuu/Units/checklist.html, #15.

http://physics.nist.gov/cuu/Units/units.html

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?

 

[JLU_EE]

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

 

[Mochuelo]

Mochuelo wrote...

http://physics.nist.gov/cuu/Units/units.html

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?

Sorry, don't take me seriously.

 

[Winfield Hill]

Michael Kissin wrote...

The MAX038 chip has recently been discontinued by Maxim, so you
might want to reconsider your choice.
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1257

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.

 

[Rich Grise]

Michael Kissin wrote...

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

 

[Don Lancaster]

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.



--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[Kryten]

Michael Kissin wrote...

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.

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?

 

[Jim Thompson]

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

 

[JLU_EE]

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

 

[Rich Grise]

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.

http://www.intersil.com/cda/deviceinfo/0,1477,ICL8038,0.html

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