It is a low power quad operational amplifier.
The "741" has come to often mean a generic op-amp IC (such as μA741, LM301, 558, LM324, TBA221 - or a more modern replacement such as the TL071). The description of the 741 output stage is qualitatively similar for many other designs (that may have quite different input stages), except:
§ Some devices (μA748, LM301, LM308) are not internally compensated (require an external capacitor from output to some point within the operational amplifier, if used in low closed-loop gain applications).
§ Some modern devices have rail-to-rail output capability (output can be taken to positive or negative power supply rail within a few millivolts).
Though designs vary between products and manufacturers, all op-amps have basically the same internal structure, which consists of three stages:
2. Voltage amplifier – provides high voltage gain, a single-pole frequency roll-off, usually single-ended output.
3. Output amplifier – provides high current driving capability, low output impedance, current limiting and short circuit protection circuitry.
IC op-amps as implemented in practice are moderately complex integrated circuits. A typical example is the ubiquitous 741 op-amp designed by Dave Fullagar in Fairchild Semiconductor after the remarkable Widlar LM301. Thus the basic architecture of the 741 is identical to that of the 301.
· Internally frequency compensated for unity gain
· Large DC voltage gain 100 dB
· Wide bandwidth (unity gain) 1 MHz (temperature compensated)
· Wide power supply range: Single supply 3V to 32V or dual supplies ±1.5V to ±16V
· Very low supply current drain (700 µA)-essentially independent of supply voltage
· Low input biasing current 45 nA (temperature compensated)
· Low input offset voltage 2 mV and offset current: 5 nA
· Input common-mode voltage range includes ground
· Differential input voltage range equal to the power supply voltage
· Large output voltage swing 0V to V+ - 1.5V
The LM124 series consists of four independent, high gain, internally frequency compensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply voltage.
Application areas include transducer amplifiers, DC gain blocks and all the conventional op amp circuits which now can be more easily implemented in single power supply systems. For example, the LM124 series can be directly operated off of the standard +5V power supply voltage which is used in digital systems and will easily provide the required interface electronics without requiring the additional ±15V power supplies.