Comments on: Parts: 133MHz-16.2kHz programmable oscillator (DS1077)

By: ben nguyen

ben nguyen — Sat, 28 Nov 2009 01:05:51 +0000

In case you can’t get the 3.3v “(L)” type..

The 5v ds1077 *might* work with a 3.3v i2c bus… the datasheet says the minimum for logic high is .7 of vcc, and minimum for vcc is 4.75, so the minimum for logic high would be 3.325 if you were to supply vcc at 4.75.

Of course you’d want to make sure whatever you’re connecting to it can tolerate 5v inputs.

Maxim has the DS1070K / DS3900K kits that could be useful in evaluating these chips:
http://datasheets.maxim-ic.com/en/ds/DS1070K.pdf

And according to this nice comparison sheet, the freq step size, at a minimum is 5khz. Which is kinda high if you’re looking for fine tuning low frequencies:
http://pdfserv.maxim-ic.com/en/an/AN230.pdf

By: tmac

tmac — Sun, 08 Nov 2009 22:06:33 +0000

Maybe it is elementary, but, can someone tell me what the resolution is on this chip. I saw where another similar chip had a 10kc resolution, but did not see resolution for this one. Im going to try to get mine working with basic stamp first and then switch to pic chip using C. If anyone already has this worked out for either platform would appreciate shared code.
Tom -WA4FYN

By: Dove

Dove — Wed, 29 Apr 2009 19:28:57 +0000

We offer programmables from multiple vendors. Request a free sample today. Not too sure if they will let me post a link so just go to google and type in dove programmable oscillators…good luck guys!

By: nuerobyte

nuerobyte — Sat, 27 Dec 2008 15:26:25 +0000

maxim? they have a realy good sampling policy, $2 may be good but FREE is better.

By: Odin84gk

Odin84gk — Mon, 01 Dec 2008 14:40:55 +0000

“Stupid question maybe?

What is the point of using 2 decoupling cap? one 0.1 and one 0.01?”

This is a question I asked for a long time, and I never got a proper answer until I read the following app note:

http://www.intersil.com/data/an/an1325.pdf

to make a long story short, the inductance within a capacitor create resonant frequencies (well, frequencies that they are less likely to attenuate). You need two different capacitors along with two different package sizes to attenuate the most amount of noise. If you don’t use different package sizes, you might as well not even bother. (See app note before replying please)

By: timour

timour — Sun, 30 Nov 2008 02:05:34 +0000

bad news for battery projects,
this chip is really power hungry.
it needs about 20ma to operate at 5V.

By: jimmys

jimmys — Sun, 30 Nov 2008 00:59:41 +0000

Ok, so what might it be used for? a sweep generator for testing, wide band frequency hopping data, adjusting for unstable carriers.. what else?

By: Andrew

Andrew — Sat, 29 Nov 2008 23:35:04 +0000

grr. someone needs to lose the thing that squashes caps to lower case…

By: Andrew

Andrew — Sat, 29 Nov 2008 23:33:53 +0000

To the guy who loves Maxim, they’re great if you want one or two, but beware if you want to buy anything between that and 50000. They’ve been bad enough that we have a policy at work that nothing sole source from Maxim is allowed unless you can justify a reason to the VP.

P.S. 10^6 Hertz is abbreviated MHz not mhz, and 10^3 Hertz is kHz, not khz.

By: therian

therian — Sat, 29 Nov 2008 19:43:31 +0000

that strange why large caps cant block high frequency, maybe because of internal inductance ?

By: matt

matt — Sat, 29 Nov 2008 11:00:53 +0000

There are two different caps because higher value ones aren’t good at blocking very high frequencies (though theoretically their high value would suggest they do) so you put a lower value one in parallel which, again theoretically, seems useless because contributes almost nothing to the total capacitance, but it can effectively block high frequencies.
It’s not uncommon to see in well designed circuits power supply lines even 3 caps in parallel, for example one 10 uF, one 100nF and one 100pF, when there are high frequencies or high self oscillation risks involved (switching power supplies, audio amplifiers, rf circuit, etc).

By: Jancans

Jancans — Sat, 29 Nov 2008 10:08:01 +0000

Stupid (incorect) answer maybe.
Smallest cap charge and discharge faster, so it smooth vcc

By: sverre

sverre — Sat, 29 Nov 2008 08:23:58 +0000

Stupid question maybe?

What is the point of using 2 decoupling cap? one 0.1 and one 0.01?

By: ngth

ngth — Fri, 28 Nov 2008 21:27:28 +0000

It’s also worth noting that there is a +3.3V version available.

By: mmalluck

mmalluck — Fri, 28 Nov 2008 20:18:45 +0000

I like Maxim parts. They’re very kind with the free samples too :-)