The 741 is the godfather of all operational amplifiers (amplifiers on a chip). Although most up-to-date designs beat it for speed, low noise, etc, it still works well as a general purpose device. One of its advantages is that it is compensated (its frequency response is tailored) to ensure that under most curcumstances it won't produce unwanted spurious oscillations. This means it is easy to use, but the down-side of this is the poor speed/gain performance compared to more modern op-amps.
The 741 is usually supplied in an 8-pin ‘DIL’ (Dual In Line) or ‘DIP’ (Dual Inline Package, or sometimes Dual Inline Plastic) package with a pinout shown above. This has proved so popular that many other competing op-amps have adoped the same package/pinout. Hence for many applications the various op-amps are ‘drop in’ replacements or upgrades for one another. These days there is a large family of 741 type devices, made by various manufacturers. Sometimes one manufacturer will make different versions which work better than others in some respect. Each has a slightly different part number, but it generally has “741” in it somewhere!
The values given below are ‘typical’ for an ordinary 741, better versions (more expensive) may give better results...
Typical values of Basic Parameters:
Note that, due to the frequency compensation, the 741's voltage gain falls rapidly with increasing signal frequency. Typically down to 1000 at 1kHz, 100 at 10kHz, and unity at about 1MHz. To make this easy to remember we can say that the 741 has a gain-bandwidth product of around one million (i.e. 1 MHz as the units of frequency are Hz).
Rail voltages : +/- 15V dc (+/- 5V min, +/- 18V max)
Input impedance: Around 2MegOhms
Low Frequency voltage gain: approx 200,000
Input bias current: 80nA
Slew rate: 0.5V per microsecond
Maximum output current: 20mA
Recommended output load: not less than 2kilOhms
Content and pages maintained by: Jim Lesurf (firstname.lastname@example.org)
using HTMLEdit2 on a StrongARM powered RISCOS machine.
University of St. Andrews, St Andrews, Fife KY16 9SS, Scotland.