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From: Thomas Magma on 18 Dec 2009 18:47
For some reason I'm having troubles finding a programmable clock divider
chip. I have a 20MHz reference clock that I need divided by 23. I would like
the option of changing this divide ratio if needed. I can't seem to find a
simple single chip solution (smaller the better). I'm currently looking at
CPLDs which is not a clean solution because of ICP. The 40103 is another
option but is border line with the max speed vs my operating voltage. I'm
also looking at using the R or N counters of a synthesizer chip if this is
at all possible.

Seems to me there should be a two wire programmable SC70 divide-by-N
available, but I can't seem to find anything close.

Any thoughts?

Thomas


From: Brendan Gillatt on 18 Dec 2009 19:08
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Thomas Magma wrote:
> For some reason I'm having troubles finding a programmable clock divider
> chip. I have a 20MHz reference clock that I need divided by 23. I would like
> the option of changing this divide ratio if needed. I can't seem to find a
> simple single chip solution (smaller the better). I'm currently looking at
> CPLDs which is not a clean solution because of ICP. The 40103 is another
> option but is border line with the max speed vs my operating voltage. I'm
> also looking at using the R or N counters of a synthesizer chip if this is
> at all possible.
>
> Seems to me there should be a two wire programmable SC70 divide-by-N
> available, but I can't seem to find anything close.
>
> Any thoughts?
>
> Thomas
>
>

Not SC70 but the On Semiconductor Fxxxx chips are really nice to use with
two-wire variants available.

- --
Brendan Gillatt | GPG Key: 0xBF6A0D94
brendan {a} brendangillatt (dot) co (dot) uk
http://www.brendangillatt.co.uk
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From: Thomas Magma on 18 Dec 2009 19:17
>
> Not SC70 but the On Semiconductor Fxxxx chips are really nice to use with
> two-wire variants available.
>

Thanks Brendan, could you elaborate on what series the Fxxxx is? I'm having
a hard time finding it.

Thomas


From: pimpom on 19 Dec 2009 00:49
Thomas Magma wrote:
> For some reason I'm having troubles finding a programmable clock
> divider chip. I have a 20MHz reference clock that I need divided by
> 23. I would like the option of changing this divide ratio if needed.
> I can't seem to find a simple single chip solution (smaller the
> better). I'm currently looking at CPLDs which is not a clean solution
> because of ICP. The 40103 is another option but is border line with
> the max speed vs my operating voltage. I'm also looking at using the
> R or N counters of a synthesizer chip if this is at all possible.
>
> Seems to me there should be a two wire programmable SC70 divide-by-N
> available, but I can't seem to find anything close.
>
> Any thoughts?
>
> Thomas

Is the 54/74HC4059 any good to you?


From: Brendan Gillatt on 20 Dec 2009 07:10
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Thomas Magma wrote:
>> Not SC70 but the On Semiconductor Fxxxx chips are really nice to use with
>> two-wire variants available.
>>
>
> Thanks Brendan, could you elaborate on what series the Fxxxx is? I'm having
> a hard time finding it.
>
> Thomas
>
>

Woops, make that FSxxxx series!

http://www.onsemi.com/PowerSolutions/parametrics.do?id=125


- --
Brendan Gillatt | GPG Key: 0xBF6A0D94
brendan {a} brendangillatt (dot) co (dot) uk
http://www.brendangillatt.co.uk
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