How to Differentiate LM741 and LM358: LM741 vs. LM358

LM741 vs. LM358 Pinout

The first visible difference is that the  LM741 's stated supply voltage is bipolar, requiring both positive and negative power. The datasheet makes no mention of a single supply operation, which we'll discuss in the following section. The LM358, on the other hand, claims that the input can go down to 0V with a 30V single-ended supply, meaning that the input range extends to the negative supply pin. The top limit, on the other hand, is 1.5 volts below the positive supply pin.

The discrepancy in input bias current is also due to the op-internal amp's structure. Although 100nA running through 10kΩ may not seem like much, it yields an error voltage of 1mV, which may or may not be significant depending on the application.

The following table shows their different specifications:

The internal circuit of LM741 is given below:

LM741 Internal Circuit

One characteristic of this op-amp that explains all three deviations from the LM358 is the input stage.

The input stage of the LM741 consists of a pair of NPN transistors that buffer a PNP transconductance gain stage, a current mirror that equally distributes current between both legs of the differential amplifier, and a current source that supplies current to the input stage.

The current mirrors and PNP amplifiers take up two diode drops from the negative supply rail, while the input transistors take up another, therefore the input must be at least three diode drops (2V) above the negative supply rail to work properly. To ensure proper operation when using a single supply, the inputs must be kept above 1.5V.

Because the input stage is buffered by only one set of transistors, the bias current is quite high.

This following  figure shows the internal circuit of LM358:

LM358 Internal Circuit

The input structure differs significantly from that of the LM741. The input stage is buffered "twice," resulting in reduced bias current. Because the input transistors are PNP, even when the input voltage is 0V, the emitters remain at 0.6V, ensuring correct operation. Consider it this way: the extra PNP buffer transistors protect the input current mirror from low input voltages by ensuring that at least one diode drop is maintained across them.

The major differences between LM741 and LM358 are shown below:

Both the LM741 and the LM358 are popular general-purpose op-amps, but when the features are compared, the LM358 comes out on top in every category.

LM741 Datasheet

LM358 Datasheet