Re: The Venerable 741

On 11/4/2024 10:21 AM, john larkin wrote:

On Sun, 3 Nov 2024 22:24:12 -0500, bitrex <user@example.net> wrote:
 

On 11/3/2024 5:17 PM, Jeroen Belleman wrote:

On 11/3/24 23:10, Jeroen Belleman wrote:

On 11/3/24 19:07, Cursitor Doom wrote:

It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?

>
I've used them in power supply regulators exposed to radiation.
Being old designs and all-NPN, they're pretty rad-hard.
>
Jeroen Belleman

>
Blimey, I just checked: It isn't all-NPN! Fortunately
for me, it still kept working under irradiation...
>
Jeroen Belleman

>
Have to go back to Jim Thompson's MC1530 era to get that:
>
<http://www.elektronikjk.com/elementy_czynne/IC/MC1530-2.pdf>

 He probably designed that without Spice.
 The first IC opamp I tried was made by GE. All NPN, with an internal
zener in the level-shift part. It was amazingly noisy.

The "natural" CMRR and PSRR of a diff pair stinks without active loads, at least on one of the rails; Thompson had to use tricks to get around that to keep the output sitting at zero when the inputs were equal

I designed some little baby-board opamps, all TO-92 transistors and
folded-over axial parts. By selecting some resistors we got sub 1 mV
offset and under 1 uV/degC, but it was tedious.
 I still have some Philbrick opamps that I found at a flea market.
 https://www.dropbox.com/scl/fi/tujdcjpvv7m4b2yo8w751/Philbricks.jpg?rlkey=19ivv2tgqmqiy9ci92lgysrz7&raw=1
 

Are those the radioactive ones?