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Clock Divider by 256

Clock Divider by 256

Clock Divider by 256

(OP)
Hello,
I want to divide 8Mhz clock to 31.25Khz.  So I guess I need a divider by 256 IC.  I haven't worked with digital logic for so long now and I can't remember which IC does this.  Would you please suggest which part I can use?  Thanks!
Best regards,

RE: Clock Divider by 256

Eight flip/flops in series.
Use a counter on a micro.

RE: Clock Divider by 256

There are, or at least were, also chips that did that.  Prescalers, etc.

31.25 sounds vaguely like a video application, so there may already be video chips that do that

TTFN



RE: Clock Divider by 256

The 74XXy93 and 74XXy90 circuits are counters that do that. The 74HCT393 from Philips is still being produced. Cost is about 30 cents in 100+ quantities. Another circuit would be the 74HC590 from Texas Instr. It is a lot more expensive, USD 1.30 in 100+ quantities.

Gunnar Englund
www.gke.org

RE: Clock Divider by 256

74VHC4040, a 12-stage counter chip with many intermediate divide values available.  A single part would do the job.  Packages from DIP to TSSOP. Price in the 50-cent range.


RE: Clock Divider by 256

itsmoked, the CD series will not work with a clock source of more than 2MHz.  The VHC can do in the hundreds of megs.


RE: Clock Divider by 256

Yup. my bad!

RE: Clock Divider by 256

HCT161/3's... sync versions.. www.ti.com

Even in this VHDL world, I think 'they' still make them.

RE: Clock Divider by 256

There are other versions of the 4040 and 4060 that will run fine at 25 MHz plus.

RE: Clock Divider by 256

Chuckles159.... A part number??

RE: Clock Divider by 256

74HC4040:
minimum max operating frequency 24 MHz @ Vcc=4.5
minimum max operating frequency 28 MHz @ Vcc=6.0
both over Tamb -40 ~ +85 C.

Typical max operating frequencies @ 25C are 82 @Vcc=4.5
90 MHz  Vcc=2, and 98 MHz @ Vcc=6.

Great 4xxx series functionality in the peppy 74HC family!

http://www.standardics.philips.com/products/hc/pdf/74hc_hct4040.pdf

Jim

RE: Clock Divider by 256

jimkirk; Thanks a lot!   I use the HC series all the time.  Easily my favorite.  I just never stumbled across the 4040/60.

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