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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I found the attached circuit on the web. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register. Calibrate with that maybe? If that’s not good enough, a high frequency crystal can be more accurate c4521 the temperature range is wide.

Sign up using Email and Password. There are lot’s of posters here who could supply it. That is fairly inaccurate in the short term, but is corrected so that the long-term drift is cd452, as many electric clocks use the mains frequency as a reference.

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

I do have a good scope once I learn to use it. If you have an 8 pin PIC laying around you’re all set to go By continuing to use this site, you are consenting to our use of cookies. Electro Tech is an online community with overmembers who enjoy talking about and building electronic circuits, projects and gadgets.


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CD4521 24-Stage Frequency Divider IC

Forums New posts Search forums. Ok, now for the important question: A different IC datasheet mentions an absolute maximum output current of 10mA, which you will be exceeding. Sign up using Facebook. Could I just not purchase an oscillator?

The Maxim part is expensive because it is Temperature Compensated, so it has circuitry that is probably individually calibrated at several temperatures. A well adjusted watch crystal is accurate enough for most applications. Of course this may not apply to your application, but i thought i would ask just in case. The logic gate just after the RESET signal is an inverter the remains of other, removed, signal lines make the inverter symbol a little unclear. 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.

Media New media New comments Search media. I have a peculiar problem involving the CD frequency divider of which I use two in a redundant configuration as shown in my schematic snippet below:. If you are lucky, any internal damage has been confined to the driver for pin 7, which you aren’t using. I’ve actually used this solution datashset and it isnt too hard to build, and a high accuracy oscillator dataeheet be found if needed. After a bit of a learning curve, I got it to alternately blink two leds and was so happy I let it run for an hour.


I think I will leave modifing a quartz clock timer for another day. I’ve looked at that inner circuit diagram many times for various reasons, but I totally overlooked the issue with Pin 7!

However, I think your LM suggestion bears serious looking at because the datasheet says it will operate over the full military temperature range. I have the Hi-Tech C cf4521 student edition.

It may also have damaged one or both of these ICs.

How do I know I am getting the newest, improved version of the ? The temperature is the same between the two units and they both operate reliably so far. Could you please post the component values? The pic stuff is something I will be working on in the future.

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.


Hero Banned May 18, It is possible that this has already damaged the IC, to a greater or lesser extent. That lets the circuit compensate for the temperature drift of the crystal, resulting in an oscillator that is far more accurate fatasheet a standard watch crystal. I’ve edited the original image from the TI datasheet that you linked, to remove extraneous parts.