Chip like LTC1799

D

DaveC

Guest
Looking for alternate part like the LTC1799.

Its a variable 1kHz - 33MHz, square wave oscillator. Uses single resister
to control frequency. 50% Duty Cycle.

Thanks
DaveC

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DaveC wrote:

Looking for alternate part like the LTC1799.

Its a variable 1kHz - 33MHz, square wave oscillator. Uses single resister
to control frequency. 50% Duty Cycle.
Click to expand...
Was it too hard to look up the linear website ?
Special functions, Silicon Oscillators.
They have a bunch of these parts.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
 
On 17 Feb 2005 07:59:18 -0600, DaveC <bobason456@hotmail.com> wrote:

Looking for alternate part like the LTC1799.

Its a variable 1kHz - 33MHz, square wave oscillator. Uses single resister
to control frequency. 50% Duty Cycle.
Click to expand...
TinyLogic schmitt trigger.

John
 
John Larkin <jjSNIPlarkin@highTHISlandPLEASEtechnology.XXX> wrote in
news:vgka11543vjsqie2qs1ajjkc9jg8bl4h5k@4ax.com:

On 17 Feb 2005 07:59:18 -0600, DaveC <bobason456@hotmail.com> wrote:

Looking for alternate part like the LTC1799.

Its a variable 1kHz - 33MHz, square wave oscillator. Uses single
resister to control frequency. 50% Duty Cycle.


TinyLogic schmitt trigger.

John
Click to expand...
Thanks John and Rene for those two rather flippant replies.

I have been down the Schmitt road but found that for any variable
resistor / fixed cap combination the frequency was not selectable.

I was asking for other manufactures of similar chips to the LTC one. If
you knew off the tops of your heads that would be quite help full, but I
can of course do my own research.

DaveC

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DaveC wrote:

Thanks John and Rene for those two rather flippant replies.
Click to expand...
How To Ask Questions The Smart Way:
http://www.catb.org/~esr/faqs/smart-questions.html

I can of course do my own research.
Click to expand...
How To Ask Questions The Smart Way:
http://www.catb.org/~esr/faqs/smart-questions.html
 
Why flippant? A cmos schmitt will oscillate with a single resistor,
and the resistor sets the frequency. It might be useful if you don't
need high frequency accuracy, it's multi-sourced, and very cheap.

[snip]


John
Click to expand...
Sorry John, was having one of those days.

I did try a schmitt res/cap did not get very good results. I'm clocking a
DAC & ADC so need mark/space within 40-60% and frequency between 20kHz &
800kHz

I dont have a scope where I am, but the ADC conversions became error
riden. When I get back to school in a week I can use a scope so will
further investigate the schmitt option.

I need inverters for this circuit any way so the hex chip is not wasted
on the board.

DaveC

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DaveC wrote:
(snip)
... I'm clocking a
DAC & ADC so need mark/space within 40-60% and frequency between 20kHz &
800kHz
Click to expand...
Does this mean that any frequency between 20 kHz and 800 kHz will do
if the symmetry stays between 40-60%, or must that symmetry hold while
the frequency is adjusted, continuously between these limits?

--
John Popelish
 
John Popelish <jpopelish@rica.net> wrote in news:4217F489.906C4CA1
@rica.net:

DaveC wrote:
(snip)
... I'm clocking a
DAC & ADC so need mark/space within 40-60% and frequency between 20kHz
&
800kHz

Does this mean that any frequency between 20 kHz and 800 kHz will do
if the symmetry stays between 40-60%, or must that symmetry hold while
the frequency is adjusted, continuously between these limits?
Click to expand...
Yes it must hold, The frequency is controlled by the user. It's for a
guitar pedal. A foot controller is used to adjust the frequency at any
time. If the 40-60% mark/space is lost then you get really awful pops as
the ADC drops samples.

DaveC

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In article <4217F489.906C4CA1@rica.net>,
John Popelish <jpopelish@rica.net> wrote:
DaveC wrote:
(snip)
... I'm clocking a
DAC & ADC so need mark/space within 40-60% and frequency between 20kHz &
800kHz

Does this mean that any frequency between 20 kHz and 800 kHz will do
if the symmetry stays between 40-60%, or must that symmetry hold while
the frequency is adjusted, continuously between these limits?
Click to expand...
How about:

A CD4060 / HC4060

IIRC the oscillator part of the LT1054 runs at about 30KHz. You can
combine the oscillator with another useful circuit.

A TICPAL22V10Z could make the oscillator and divide by two with some extra
sections to make other glue logic.





--
--
kensmith@rahul.net forging knowledge
 
I read in sci.electronics.design that John Larkin <jjSNIPlarkin@highTHIS
landPLEASEtechnology.XXX> wrote (in <n8kf11phfufl4qhulsku5e8pgam700q9s9@
4ax.com>) about 'Chip like LTC1799', on Sat, 19 Feb 2005:
What's bleeding-edge about a mediocre-accuracy oscillator?
Click to expand...
It operates at around 30 THz? (;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
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