old parts
usually when a good company like MA-Com or HP (now Agilent) discontinue a
part it is because they have a better one to replace it.
Motorola does the debt spiral effect by eliminating low sales volume parts
which makes customers not design their parts into future products which
lowers the sales volume of the remaining parts which gets the low sellers cut .....
(cycle n times until no parts are left)
National Semiconductor does the same thing. Through hole packages were
eliminated when the dropped to 1% of sales. I avoid them for the same
reason as Motorola, the sole source parts will be discontinued in the future.
You might examine the new parts from MA-Com and Agilent to see which one
has the same package and adequate or better performance. Sometimes a
telephone call or e-mail to their local rep will get you the replacement part
number.
I always try to design in parts with multiple sources.