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Absolute Maximum Ratings. The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should . Fairchild µA description. The µA is a general-purpose operational amplifier featuring offset-voltage null capability. The high common-mode input voltage. uA Frequency-compensated operational amplifier. Other names for this product: , A, uA,. Courtesy/Thanks to: Fairchild Semiconductors.

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Previous fairchld Next post. By calculating slew rate we can easily find out the rate in which the output of the op-amp changes in response to changes in the input frequency. The output transistors in the are larger than the other transistors and have a different structure in order to produce the high-current output. The more common variant has 24 transistors, while the less common variant has 20 transistors.

Op-Amp Tutorial, op-amps, Operational Amplifier

Fairchilv theory, the dc output voltage will be zero if both the inputs of the IC are connected to the ground. The 25pF capacitor in the has a very small value but takes up a large fraction of the chip’s area. Therefore, its absolute value is listed in the datasheet. Studying data sheet schematics, I found that chips can be be divided into two categories based on the circuits for the second stage and output stage. The following page uses this file: They consist of a circular emitter Psurrounded by a ring shaped base Nwhich is surrounded by the collector P.


If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file.

The value for IC may go as high as 2megaohms. Both resistors farichild at the same scale below, but the pinch resistor has ten times the resistance.

Using one large resistor and current mirrors is more compact and more accurate than using multiple large resistors. In addition to the very large size difference, the silicon doping is different.

Dangerous concentrated acid is required to dissolve the epoxy package and see the die.

But, this simple addition has made this IC evergreen in the electronics world and is still manufactured by different companies in different versions and specifications, and is made recognizable by adding the famous number in the series.

The result is a transistor will have poor gain if the fairchkld and emitter are swapped.

Your email address will not be published. By changing the POT value, the output offset voltage can be reduced to 0V. This is why short circuit protection is provided.

File:Fairchild uA opamp jpg – Wikimedia Commons

The differential pair The second important circuit to understand is the differential pair, the most common fairchilx subcircuit used in analog ICs. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.


Thus, the differential pair is a surprisingly simple circuit that routes current based on the difference in input voltages. The range through which the POT is varied to fajrchild the input offset voltage is the offset voltage adjustment range. Transient response along with steady state response constitutes that total response of a practical network to a given input.

File:Fairchild uA741 opamp 6920.jpg

According to Analysis and Design of Analog Integrated Circuits differential pairs are “perhaps the most widely used two-transistor subcircuits in monolithic analog circuits. A high-current PNP transistor inside the op amp How resistors are implemented in silicon Resistors are a key component of analog chips.

As you can see from the die photo, the collector and emitter are very different in a real transistor. Large signal voltage gain is the ratio between the output voltage and the voltage difference between the two input terminals.

This current is then duplicated by multiple current mirrors, providing controlled currents to various parts of the chip.

This is the job of the differential pair. It saves space to use a current mirror instead of a resistor whenever possible. The figure is show below.

The output from the differential amplifier goes to the second gain stage, which provides additional amplification of the signal.