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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Therefore, after each going through an inverter, the two inputs to the NAND gate in the diagram are both High, and its output is Low.

Post as a guest Name. If you use the internal RC oscillator, you dont even need a crystal or external oscillator. The Maxim part is expensive because it is Temperature Compensated, so it has circuitry datahseet is probably individually calibrated at several temperatures. You shouldn’t be grounding it. Thank you for the analysis and for datashert the effort to prepare such an exhaustive answer! Another solution is a Slightly clearer internal logic diagrams of the IC are available in the datasheets from: Most GPS receivers can give a 1 pulse per ce4521 output that is seriously accurate as it comes from the frequency standards in the satellites.

Therefore its output is now High.

Ok, now for the important question: Of course this may not apply to your application, but i thought i would ask just in case. Be only a matter, I should think, of adjusting the count in the code. One Second Time Base.


CD4521 24-Stage Frequency Divider IC

Started by fastline Yesterday at 8: Or you can use an external source. A different IC datasheet mentions an absolute maximum output current of 10mA, which you will be exceeding.

Media New media New comments Search media. I found the attached circuit on the dd4521. Could test it out with that. 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.


Welcome to our site! Not everyone likes or 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.

As colin55 said in post 2, just use the 1HZ output from a 1. 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. Also, as I mentioned, these ICs might already have been partially damaged, and require replacement if you want to be confident of their future behaviour and reliability. I’ve edited the original image from the TI datasheet that you linked, to remove extraneous parts.

CD Datasheet, PDF – Alldatasheet

I do want one pulse per second. Diver Well-Known Member May 18, That is fairly inaccurate in the short term, but is corrected so that the long-term drift is zero, as many electric clocks use the mains frequency as a reference.

I could have used 60hz from the mains, but wanted to be independent of an external source. How about this datasheet? However, I think your LM suggestion bears serious looking at because the datasheet says it will operate over the full military temperature range.


I wasn’t born with CD-series logic in hand so maybe I’m missing out something obvious After a bit of a learning curve, I got it to alternately blink two leds dataheet was so happy I let it run for an hour.

I will do a search on this site and google as well. Hero Banned May 18, If that’s not good enough, a high frequency crystal can be more accurate if the temperature range is wide. I’ve looked at that inner circuit diagram many times for various reasons, but I totally overlooked the issue with Pin 7!

I think I will leave modifing a quartz clock timer for another day.

After two more inverters, you see that OUT1 pin 7 is also driven Low. The MCU is still an option but it would need a crystal so the counter datasheet be more convenient.

Below is the relevant part of my PCB layout – your wisdom will be much appreciated! 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. Cheap, easy, and accurate.