Am I right in thinking the 741 was.....

[John Larkin]

Hello John,


I liked the uA709 better. Compared to the 741 it felt like a hotrod but
that also meant you could wreck out easier. Of course, the hottest of
all amps from those days is the uA733 which was also remarkably cheap
almost right from the start. I made a lot of RF gear with those. There
were times when a 733 sold for about the same price as a 741 in the
local stores (in Germany) but you got a Kawasaki instead of a moped.



Nice, but expensive.

733's were hot stuff once, but they weren't opamps, not feedback
friendly at all. Nowadays you can buy a real 2 GHz opamp.

John

 

[qrk]

On Tue, 17 Oct 2006 16:18:36 -0700, John Larkin

[snippage]

What's a good gp opamp now? I like the LM7301, SOT-23, r-r i/o, OK DC
specs, 4 MHz, 5v to +-15v supplies.

John

I like the AD8038 / AD8039. Low power for the speed.
300 MHz, 400 V/us, 1.5 mA max, 3 to 12 V supply.

 

[Jim Thompson]

Gosh Jim, are there chip-designer groupies?

John

I doubt it ;-)

I had two female techs at GenRad... a babe and a grandmother.

...Jim Thompson

 

[Genome]

Sure they do.

...Jim Thompson

OK, they pretend to be interested in 'meanignfull 'conversation about the
741 but are too busy drinking 14 rum and cokes and want some cock to stuff
up their fannies afterwards.

Is it my fault you didn't change the world?

DNA

 

[martin griffith]

What's a modern-day replacement for NE5532?

SioL

It is still the 5532, but Natsemi has just released LM4562, dont know
how it works out costwise


martin

 

[Joerg]

Hello Ban,


Yes, that's what made it so cheap. It was in VCRs, hard drives and other
mass products. Maybe still is, to some extent. But it doesn't have to be
used for video. Only one of my apps for it was video ;-)

balanced out, but only +/-6V supply

That balanced architecture turned many people off but OTOH you got a
real rocket for under a Dollar. It could make a nice AGC amp if you
isolated the control element (FET etc.) properly and made sure it was
mostly resistive. The alternatives in those days (HA2540, IIRC) cost a
whole lot more and guzzled way more power.

 

[Joerg]

Hello John,

733's were hot stuff once, but they weren't opamps, not feedback
friendly at all. Nowadays you can buy a real 2 GHz opamp.

They still seem to be hot stuff, you can buy them under $0.40/1k. Even
today that is a bargain. No feedback but the gain control at the emitter
nodes is nice.

 

[Jim Thompson]

Hello Ban,



Yes, that's what made it so cheap. It was in VCRs, hard drives and other
mass products. Maybe still is, to some extent. But it doesn't have to be
used for video. Only one of my apps for it was video ;-)



That balanced architecture turned many people off but OTOH you got a
real rocket for under a Dollar. It could make a nice AGC amp if you
isolated the control element (FET etc.) properly and made sure it was
mostly resistive. The alternatives in those days (HA2540, IIRC) cost a
whole lot more and guzzled way more power.

Or my "blender" version, the MC1545 ;-)

...Jim Thompson

 

[Joerg]

Hello Jim,

Or my "blender" version, the MC1545 ;-)

Couldn't find that one, even Lansdale doesn't show it under Motorola Linear.

 

[Jim Thompson]

Hello Jim,


Couldn't find that one, even Lansdale doesn't show it under Motorola Linear.

Google on it. There are data sheets everywhere.

A few months ago I had an inquiry from a MIL customer about making a
new version, but nothing came of it.

...Jim Thompson

 

[Joerg]

Hello Jim,

Google on it. There are data sheets everywhere.

Found it. Not a place to purchase some but a data sheet. Looks like you
can't do an AGC amp with it but the mux part sure is nice. Muxes seem to
be one area where younger engineers run into trouble, unless it's all in
one chip and they can't mess it up.

A few months ago I had an inquiry from a MIL customer about making a
new version, but nothing came of it.

Yeah, tire kicking. It seems to be on the rise :-(

 

[Eeyore]

733's were hot stuff once, but they weren't opamps, not feedback
friendly at all. Nowadays you can buy a real 2 GHz opamp.

I tended to use the uncompensated 748 over the 741 back then. In practice
they seemed to be quieter too. For audio, there was also the trick of tying a
resistor from output to one of the supply rails ( I think negative was
preferred ) to avoid crossover distortion by forcing the output into Class A.

Graham

 

[Eeyore]

It is still the 5532, but Natsemi has just released LM4562, dont know
how it works out costwise

*LOTS* more.

5532s are jellybeans now.

Also see NJM4580 ( and related family members ).

The TLx7x series soldiers on too.

Graham

 

[John Larkin]

What's a modern-day replacement for NE5532?

SioL

OP227 maybe. LT1124 is even better, but the pinout is weird.

The lowest voltage-noise single opamp is probably the LT1028, around 1
nv/rtHz.

John

 

[Joerg]

What's a modern-day replacement for NE5532?

6AQ8/ECC85, 12AT7/ECC81

 

[martin griffith]

*LOTS* more.

5532s are jellybeans now.

Also see NJM4580 ( and related family members ).

The TLx7x series soldiers on too.

Graham

OK , lets just separate them into the ones that can drive the ever so
fictious 600 ohms


martin

 

[Eeyore]

OK , lets just separate them into the ones that can drive the ever so
fictious 600 ohms

Most of the above do. The TI bifets are slightly less keen on it though. The
better NJMs are specced for 400 ohms in fact.

Graham

 

[Ethan]

The lowest voltage-noise single opamp is probably the LT1028, around 1
nv/rtHz.

John

Does anybody have a suggestion for a low noise quad op-amp?

I am looking for options for a transimpedance photodiode amplifier. I
have been thinking about a MCP6294, 8.7nV/rtHz and 3fA/rtHz. Microchip
of all people seems to make decent op-amps.

Ethan

 

[Ian Bell]

1) Some sort of weirdo **** up invented to demonstrate the designers
ability to be clever.

2) Some sort of weirdo **** up invented by the designer after management
stuck the oar in because the original design was just too simple and they
wanted everyone else to have a hard time ripping it off.

3) It makes obvious sense given the constraints of processing at the time
it was designed.

4) It's just obvious!

5) The designer was the only person who could come up with this shit at
the time but drank beer down the pub with his mate(s) and they hatched a
plan for the gradual release of shit to different companies.... at a
price.

DNA

None of the above. It was simply the first unity gain compensated op-amp.

Ian

 

[John Larkin]

Does anybody have a suggestion for a low noise quad op-amp?

I am looking for options for a transimpedance photodiode amplifier. I
have been thinking about a MCP6294, 8.7nV/rtHz and 3fA/rtHz. Microchip
of all people seems to make decent op-amps.

Ethan

We never buy quads. Two duals aren't much bigger than one quad, and
placement is usually easier. Single SOT-23s are very nice, too, but
the best performance amps seldom come in that package, must be die
size or thermal limits.

Most of the Microchip parts seem to be 5-volt-max stuff.

I'm lately using current-mode opamps as TIAs. They're not low-noise,
but I have lots of light, so that's not a problem. But they're
blinding fast.

John