are modern IC minimum specs accurate/precise ?

[robb]

i was re-checking the specs on the A618SEP replacement for my
SN75518N ....
advertised as drop in replacement

and i noticed that the minimum clock for A6818 is 10 MHz @ 5v
and the SN75518 has a 1-5 MHz range @ 5v which is quite a ways
out of spec from the replacement's specs

do you suppose the A6818 will work in the 1-5 MHz range ?

what is the experience with these sorts of operational minimums ?
i guess they would not state a minimum if there was no real
minimum ?

if it turns out that the a6818 does not function due to spec
differences
what would (is there something) one could do to get this
replacement to work ?

i have not tried yet but imagined this may be a problem and did
not wnat to start etching my adapter if there is some
solution/control chip i will need to add to my adapter

thanks for any advice,
rob

 

[Don Bowey]

On 9/30/07 12:18 PM, in article 13fvt9k4l3ta6d6@corp.supernews.com, "robb"
<some@where.on.net> wrote:

i was re-checking the specs on the A618SEP replacement for my
SN75518N ....
advertised as drop in replacement

and i noticed that the minimum clock for A6818 is 10 MHz @ 5v
and the SN75518 has a 1-5 MHz range @ 5v which is quite a ways
out of spec from the replacement's specs

The A6818SEP spec sheet has a strange way of expressing the clock frequency
limits.

Look at the far left (Characteristics) clock column - It says they are going
to express the MAXIMUM frequency. Then in the Limits column for 5V they
give a Minimum of 10 MHz and a Typical of 33 MHz.

What that means is, the maximum frequency is at least 10 MHz, but most
devices will work to 33 MHz. You may use a frequency of 1-5 MHz and be
assured it will work.

I'd call their expression a negative positive

do you suppose the A6818 will work in the 1-5 MHz range ?

what is the experience with these sorts of operational minimums ?
i guess they would not state a minimum if there was no real
minimum ?

They didn't.

if it turns out that the a6818 does not function due to spec
differences
what would (is there something) one could do to get this
replacement to work ?

i have not tried yet but imagined this may be a problem and did
not wnat to start etching my adapter if there is some
solution/control chip i will need to add to my adapter

thanks for any advice,
rob

 

[robb]

"Don Bowey" <dbowey@comcast.net> wrote in message
news:C32551B9.79079%dbowey@comcast.net...

On 9/30/07 12:18 PM, in article
13fvt9k4l3ta6d6@corp.supernews.com, "robb"
some@where.on.net> wrote:

and i noticed that the minimum clock for A6818 is 10 MHz @ 5v
and the SN75518 has a 1-5 MHz range @ 5v which is quite a
ways
out of spec from the replacement's specs

What that means is, the maximum frequency is at least 10 MHz,
but most
devices will work to 33 MHz. You may use a frequency of 1-5
MHz and be
assured it will work.

thank you,

i was getting all psych'd about etching this board and then the
specs were not looking good.
thanks Don for the big sigh of relief,
rob