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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However, I think your LM suggestion bears serious looking at because the datasheet says it will operate over the full military temperature range. I cut datsheet traces and true enough, the temperature is now close to ambient at all times! Again, kudos to brhans for spotting the problem first. A well adjusted watch crystal is accurate enough for most applications. That will cause a significant current to flow through the IC and also cause its temperature to rise, as you measured.

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. To create a one second time base, I went looking for this: 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:.

The Maxim part is expensive because it is Temperature Compensated, so it has circuitry that is probably individually datashedt at several temperatures. I do have a good scope once I learn to use it.

Ok, now for the important question: Of course this may not apply to your application, but i thought i would ask just in datasheeg. Diver Well-Known Member May 18, Note that the Datasjeet datasheet is a scan of an earlier Harris Semiconductor datasheet, so it does not have the high resolution of typical modern datasheets. LM oscillator is the simplest and cheapest 1 cap, four resistors and maybe a potentiometer for perfect adjustment 2.


Calibrate with that maybe? 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.

One Second Time Base

Can I use the 3 volt type in a five volt circuit? Are you really after a 1Hz oscillator, or a 0. Price depends on stability, and can be as good as 0.

I have to admit that I like that crusty old scan quite a bit. Due to the low resolution of web images, I can not make catasheet the text very well. Sign up using Facebook. With a 12F and a Hz watch crystal you could have a pretty accurate 1Hz timebase.

What could be causing this?

CD Datasheet, PDF – Datasheet Search Engine

Email Required, but never shown. Media New media New comments Search media. Therefore, after eatasheet 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. I have the Hi-Tech C compiler student edition. The internal logic diagram for the IC explains the problem – see diagram below.

I will do a search on this site and google as well. Heck, I could even tweak the count cs4521 adjust it’s accuracy I’ll bet.

CD4521 24-Stage Frequency Divider IC

I have several pics and a programmer and am somewhat aware of it’s possibilities in this case. Therefore its output is now High. That lets the circuit compensate for the temperature drift of the crystal, resulting in dataxheet oscillator that is far more accurate than a standard watch crystal. 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. I like Hero’s suggestion because, if I understand correctly, it is most likely as accurate as any watch oscillator and simple to build without cd4251 need of additional dayasheet such as a frequency counter which I do not have for calibration.


Cheap, easy, and accurate. Thread starter jack Start date Datsaheet 17, The temperature is the same between the two units and they both operate reliably so far. However, this extra current will be less than in the case below. Hero Banned May 18, Thank you for the analysis and for taking the effort to prepare such an exhaustive answer!

Maybe they did not update their datasheet. I can not help but smile. It is possible that this has already damaged the IC, to a greater or lesser extent. I’ve edited the original image from the TI datasheet that you linked, to remove extraneous parts. Forums New posts Search forums. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.