The chip isn’t obsolete. Or, at least I couldn’t find that stated on TI’s site.The LM2907 is typically used for frequencies in the low kHz range at most. I can't find any upper limit in the datasheet, but I can't see it working for anything much higher. Incidentally, that IC is now obsolete.
I don’t think the chip usable past 10khz.
I think even 8khz is pushing it...