This is a problem that really makes me upset. Needed chips going obsolete with no replacement parts or equivalent parts. So I opened this topic so you can tell what chips you wouldn't wish to go obsolete or disappear.
So, here are my preferences:
DM9368 - It is the only 7-segment decoder capable of hexadecimal output and is already obsolete. It as the option of lead zero blanking, very handy in some cases. In fact, it should exist a CMOS version of it.
74LS47 - This 7-segment decoder/driver is also capable of lead zero blanking, unlike the CMOS 4511 only capable of unconditional blanking and has a very unuseful lamp test that most people won't use when driving LED displays (perhaps it is for testing gas lamps).
LM1036 - This is the only readily available audio processor made by National. For very obvious reasons, it shouldn't disappear. Unlike other audio processors, it is controlled by voltages and not by currents.
LM386 - This is a 1W audio amplifier, good for small radios. Very simple to use.
So, here are my preferences:
DM9368 - It is the only 7-segment decoder capable of hexadecimal output and is already obsolete. It as the option of lead zero blanking, very handy in some cases. In fact, it should exist a CMOS version of it.
74LS47 - This 7-segment decoder/driver is also capable of lead zero blanking, unlike the CMOS 4511 only capable of unconditional blanking and has a very unuseful lamp test that most people won't use when driving LED displays (perhaps it is for testing gas lamps).
LM1036 - This is the only readily available audio processor made by National. For very obvious reasons, it shouldn't disappear. Unlike other audio processors, it is controlled by voltages and not by currents.
LM386 - This is a 1W audio amplifier, good for small radios. Very simple to use.