CD Datasheet, CD Stage Frequency Divider Datasheet, buy CD Data sheet acquired from Harris Semiconductor. SCHS Page 2. Page 3. Page 4. Page 5. Page 6. Page 7. Page 8. IMPORTANT NOTICE. Texas Instruments. all relevant TOSHIBA information, including without limitation, this document, the specifications, the data sheets and application notes.

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Ok, now for the important question: I agree and would like to use your suggested circuit.

The solution there is to use a 50 percent duty cycle one-half Hertz oscillator. I do want one datasheft per second. I have several pics and a programmer and am somewhat aware of it’s possibilities in this case.

The circuit I posted also has 0. Below is the relevant part of my PCB layout – your wisdom will be much appreciated!

Digital-IC-Lexikon –

Articles Top Articles Search resources. Sign up or log in Sign up using Google. The reason i ask is because many times a person is looking for a one half Hertz oscillator but they ask for a 1Hz oscillator. Most GPS receivers can give a 1 pulse per second output that is seriously accurate as it comes from the frequency standards in the satellites.

Replacing a 4 pin leaded inductor with a 2 pin Started by cr4521 Yesterday at I’ve looked at that inner circuit diagram many times for various reasons, but I totally overlooked the issue with Pin 7!

It’s a very simple circuit and is not too sensitive to voltage variations, and accuracy can be adjusted to very very close to perfect if you have a frequency counter available. You must log in or register to reply here. I’ve edited the original image from the TI datasheet that you linked, to vatasheet extraneous parts.


I can breadboard other dividers to the circuit, dztasheet.

One Second Time Base | Electronics Forum (Circuits, Projects and Microcontrollers)

How accurate do you need the timebase? Home Questions Tags Users Unanswered.

A well adjusted watch crystal is accurate enough for most applications. Slightly clearer internal logic diagrams of the IC are available in the datasheets from: By continuing to use this site, you are consenting to our use of cookies.

Your information is very interesting. That lets the circuit compensate for the temperature drift of the crystal, resulting in an oscillator that is far more accurate than a standard watch crystal.

As mentioned in the excellent comment from brhansthe problem is the connection of pin 7 to Gnd V SS on your schematic. I do have a good scope once I learn to use it. Diver Well-Known Member May 18, Therefore you are effectively trying to cd4251 a short-circuit at pin 7 of the IC, limited mainly by datasyeet IC’s output driver current capability.

I cut some traces and true enough, the temperature is now close to ambient at all times! I like Hero’s suggestion because, if I understand correctly, it dd4521 most likely as accurate as any watch oscillator and simple to cd5421 without the need of additional equipment such as a frequency counter which I do not have for calibration.

CD4521 24-Stage Frequency Divider IC

What could be causing this? Could I just not purchase an oscillator?


The difference is, if the oscillator is going to be used as a 1Hz time base for say a frequency counter, the frequency really needs to be one half Hertz, not 1Hz, because the period of time the 1Hz cd452 is high is only one have second and they really want 1 full second. Could you please post the component values?


If the code is adjusted for the particular RC oscillator on chip, the daatasheet can be very very good and be stable at room temperature too with only a tiny variation for plus and minus say 10 degrees C. Another solution is a With a 12F and a Hz watch crystal you could cr4521 a pretty accurate 1Hz timebase. Not everyone likes vd4521 wants to use microcontrollers and i understand this, so another solution is to use an LM and a capacitor and a few resistors to make a 1Hz oscillator.

By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. I was thinking the pic may not be accurate enough and failed to realize that it could simply serve as a counter running off a crystal. The pic stuff is something I will be working on in the future.

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