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The advantages of LM741H(metal can package) over LM741 IC

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hansika

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opamp doubt

HI every one,
can any one please tell me the advantages of LM741H(metal can package) over LM741 IC.
 

Re: opamp doubt

why a 741 metal can package?

why not plastic 8pin dip?

any specific temp you have?

srizbf
22ndmay2010
 

Re: opamp doubt

741? What did you do, find some in an old cave somewhere?

No advantage, unless you need a hermetically sealed one for some military reason.
 

opamp doubt

The 741 opamp is 41 or 42 years old, has horrible performance and should be buried.

I used TL071, TL072 and TL074 audio opamps for the last 30 years. They have FET inputs so I don't need to calculate their bias current, they have very low distortion and low noise, they work from a supply as low as 7V and their bandwidth is 11 times higher than a 741 opamp.

I have never seen an opamp in a metal case.
 

Re: opamp doubt

erikl said:
See here.
Click to expand...
That metal-cased lousy old 741 opamp was made in 1979. I was too busy disco'ing and celebrating the birth of my daughter to notice the metal cases in those days.

I gave up on the poor performance of the 741 opamp about 4 years earlier when I started using much better TL071, TL072 and TL074 audio opamps in plastic DIP packages.
 

Re: opamp doubt

thank you for quick replies, my requirement is i need to do signal amplifying from (0 to 5V) input range to (6 to 18V) output range and i am having 24V and 5V supplies in my circuit can any one please tell me how can i do it
 

opamp doubt

What is the signal you want to amplify?
DC voltages from 0V to +5V?
Music from an MP3 player?
Video?
 

Re: opamp doubt

That metal-cased lousy old 741 opamp was made in 1979.
Click to expand...
The device has been introduced by Fairchild in 1968. At least during the 70th, most professional instruments used metal canned analog ICs,
although plastic DIP package has been available since early 70th. I guess, there have been some doubts regarding long-term reliability.
 

Re: opamp doubt

Ya it is DC voltage only(0 to +5V)..........
 

Re: opamp doubt

Hi!

i am just learning OPamps...

i am attaching one circuit for your specification hansika...

Vin = 0 to 5V
Vout = 6 to 18V
Vref = 5V;

See this i think this has to work..

cheers...
 

Re: opamp doubt

thanks for your schematic, but when i see the data sheet of OPA350 it is mentioned that the maximum supply voltage is 5.5V but in schematic we are giving supply 20V is it correct..... please clarify this, thanks in advance

Added after 4 hours 7 minutes:

can you please tell me the how this circuit will work
 

opamp doubt

Correct.
The OPA350 opamp with a max supply voltage of only 5.5V is the wrong opamp for the circuit that has an 18V max output and a 20V supply.
 

opamp doubt

Unfortunately, the circuit dimensioning is wrong as well. But by using a different OP and correcting the resistance ratios, it can serve the intended purpose.
 

Re: opamp doubt

but when i simulating the circuit in multisim it is giving correct values only i.e for 0V input o/p is 6V & 5V i/p output is 18V, can you please explain me how this circuit is failing
 

Re: opamp doubt

Sorry, I read a wrong reference voltage of 2.5 from the schematic. It's working
correctly with Vref = 5.
Code: 
Vout = (2/3* Vin + Vref/3)*3.6 = 2.4*Vin + 1.2*Vref
 

Re: opamp doubt

i am late.....

see, i just took some op amp from TI and completed this circuit....
this is theoretically verified one....

see the reference voltage is 5V it's name is V2 don't confuse....\

i didn't tested practically...u can test and verify it. Use the formulas and resistor ratios as given .....because those i got from the input output voltages you given in the post...

Hope this helps....

cheers....
 

Re: opamp doubt

thank you for the explanation, when i am doing the circuit practically with 741 IC(for understanding) it is giving me 40mV to 60mV offset, why this offset is coming , in this forum some friends are suggesting TL071, can i use the opamp for the DC amplification.
 

Re: opamp doubt

chk the opamp which is having VCC >=20V and it should be able take input 0v.
i can't suggest an opamp suitable for this....because i am also new to practical Op-amp world. may our friends may help...

let's see..

......................................................................................................................
To reduce the offset effects R1,R2 parallel combination should be almost equal to Rf and Rg parallel combination.
 

Re: opamp doubt

Part of the offset error can be expected due to OP bias currents and unsymmetrical source resistance at inverting and non-inverting inputs.
The resistances can be recalculated to reduce the offset. TL071 or other FET OPs have low bias currents, that can be neglected in this circuit,
it's the better choice. If you intend very low offset voltages, you may consider OP07 (or a newer successor) instead.
 

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