Operational amplifier lm741 transistors characteristics

Terlaud guillaume

Other Parts Discussed in Thread: LM741

Hello,
I'm a French student and in june I will have to give a presentation of a scientific project carried out during the year. My project consists in making an operational amplifier lm 741. For this I used the diagram as a model of a 741 op amp which I found on your website (www.ti.com/lit/ds/symlink/lm741.pdf). However I have not managed to find the transistor characteristics. I guess TI keep these datas confidential but given that the OA lm741 is made technologically obsolete by new types of operational amplifier, can I ask you for the characteristics of the transistors (Q1, Q2,...) in this OA lm741.
I would be grateful if you would answer me whenever possible.

over 13 years ago

0 Ron Michallick over 13 years ago

TI__Guru**** 166566 points

Terlaud,

All the NPN and PNP transistors except Q14 and Q20 are minimum size for the design time (which is quite large by today's standards). The output transistors are larger because the current can be higher. You can use any generic small signal NPN and PNP transistors. 2N3904 & 2N3906 for example.

0 Terlaud guillaume over 13 years ago in reply to Ron Michallick

Prodigy 20 points

First of all, thank you for your answer.

Does 2N3904 and 2N3906 transistors will be sufficient to Q14 and Q20 or should I use two transistors capable of being traversed by a current higher than 200mA?? If this is not the case can you give me an example of a conventional transistor which can be used?

0 Ron Michallick over 13 years ago in reply to Terlaud guillaume

TI__Guru**** 166566 points

Terlaud,

Resistor R9 and R10 will limit the current to much less than 200mA. All the transistors can use the same NPN and PNP .

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Operational amplifier lm741 transistors characteristics