I have a small two stage BFR91A based preamplifier, and I would like to replace this with a transistor array of similar performance as far as concern Ft and gain.
Any suggestions which array IC to use?
I very much doubt that any array would exist. The mechanical demands of an array would make the performance unattainable and even if one did exist, packaging microwave transistors in a confined space would make a PCB virtually impossible to design.
I very much doubt that any array would exist. The mechanical demands of an array would make the performance unattainable and even if one did exist, packaging microwave transistors in a confined space would make a PCB virtually impossible to design.
For a discrete fun like me, using an array seems odd indeed. The reason are copy reasons. I want to build something but I do not want to be easy to be coppied. An array with deleted markings makes this more difficult.
You'll use arrays for a reason, e.g. building differentail amplifiers or other circuits that take advantage of temperature and parameter matching. Unlikely for a trivial two-stage amplifier.
UHF-1 is old, maybe obsolete, may account for pricing (let the die
last by jacking up the unit price).
It was a big deal in the early '90s. 8GHz NPN, 4GHz PNP , silicon on
insulator. I don't think there were any new products made on it after
the Intersil IPO. You can't do high band PAs when your fT is less than
2X the carrier and the market moved faster (way) than their process
development group did. They had the first WiFi modem chip set
but got left in the dust (the majority of the chip set was outsourced
for foundry even then). But the WiFi story propelled the IPO.
THAT Corp makes higher voltage transistor arrays with NPN fT in
the 700MHz range, PNP around 300MHz, >30V BVceo. Similar idea
to the UHF-1 arrays, couple of flavors. Could be adequate for 30MHz
depending on gain-per-stage. Either Digi-Key or Mouser, forget which.