[time-nuts] Divide by five

[Said Jackson]

The 74F161 is only rated at 90MHz over temp (TI) and 120MHz or 100MHz (unclear) at 25C and then only as "typical" without any max freq being indicated at all in the datasheet (Fairchild).

So thats pretty much a no-go for any commercial product even at 'only' 100MHz..

Again for a one-off it may work, but not for a production unit that has to be guaranteed..

For a divide by 10 it would work if there is a 74AC74 type prescaler..

Bye,
Said

On Nov 7, 2014, at 21:19, Bob Bownes <bownes at gmail.com> wrote:

> I'm surprised no one has suggested 74F161 or other F series. Power hungry, but rated to in excess of 100mhz, some vendors as high as 120mhz, at ordinary temps. I will have to look, but I might have a tube or two of them in the basement. I know I have most of the other 74F.
> 
>> On Nov 7, 2014, at 23:20, Said Jackson via time-nuts <time-nuts at febo.com> wrote:
>> 
>> Joe,
>> 
>> This puppy can go to 166MHz over temp and has standard 100 mil pin spacing if you put it into a socket: ATF16V8C
>> 
>> I have not used PALs since 1992 but I used to be extremely fond of the 16R8 and 22V10 types back then.
>> 
>> This is a 16V8 that will do your divider in no time:
>> 
>> http://www.digikey.com/product-detail/en/ATF16V8C-5JX/ATF16V8C-5JX-ND/1027054
>> 
>> Best of all its available and only ~$3..
>> 
>> Said
>> 
>> Sent From iPhone
>> 
>>> On Nov 7, 2014, at 19:37, Joseph Gray <jgray at zianet.com> wrote:
>>> 
>>> Looks like I can get the 74AC161 in DIP from Mouser. Thanks to everyone for
>>> the suggestions. I still like DIP for prototyping on breadboards.
>>> 
>>> Joe Gray
>>> W5JG
>>> 
>>> 
>>>> On Fri, Nov 7, 2014 at 4:45 PM, Alex Pummer <alex at pcscons.com> wrote:
>>>> 
>>>> 
>>>> 
>>>> check if you could get a 74AC161, which could be connected  to divide by 5
>>>> at 125 MHz see here http://ecee.colorado.edu/~mcleod/pdfs/IADE/references/
>>>> 74AC161.pdf to be sure to work at 125MHz run with 5,5 to 6V...
>>>> 
>>>> 73
>>>> Alex
>>>> 
>>>> 
>>>> 
>>>>> On 11/7/2014 1:12 PM, Joseph Gray wrote:
>>>>> 
>>>>> I need to divide a 125 Mhz clock by five. I have looked on Mouser and
>>>>> every
>>>>> chip I find is either obsolete or in SMT. Can anyone recommend a chip that
>>>>> is fast enough and comes in DIP?
>>>>> 
>>>>> Joe Gray
>>>>> W5JG
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