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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File:Fairchild uA741 opamp 6920.jpg
The maximum input offset current value for IC is nA. Characteristics of transient response includes rise time and percent of overshoot. Input Bias Current of op-amp IC.
NPN transistors are rectangular, while PNP transistors have circular emitters and bases with a circular metal layer on top. The component I photographed is the Analog Devices ADbut that datasheet doesn’t have a schematic. The output from the differential amplifier goes to the second gain stage, which provides additional amplification of the signal.
The interactive fairchkld viewer below provides more explanation.
Differential Input Resistance is the equivalent resistance that is measured from any one of the input terminals by keeping the other terminal connected to ground. I used Magic Lantern set at 10 steps per image to automate the focus stepping.
An op amp takes two input voltages, subtracts them, multiplies the difference by a huge valueor moreand outputs the result as a voltage. If you’re interested in how analog chips work, I strongly recommend you take a look at Designing Analog Chips.
Fairchild Oral History Panel. The typical value for IC is 1. I started with a op amp that was packaged in a metal can above.
This can be found out by connecting a 10K POT between the pin 1 negative offset null and pin 5 positive offset null and the wiper of the port should be connected to the ground. The tiny wires are 1 mil in diameter which is about 3 to 4 times smaller than a human hair! This power is called power consumption and typical value is 85mW. How I photographed the die Fwirchild circuit usually come in fakrchild black epoxy package.
The supply current is rairchild current drawn by the IC from the power supply. The output transistors must support 25mA, compared to microamps for the internal transistors. The photo below shows one of the output transistors.
The op-amp has pins 1 and 5 marked as offset null to determine the offset voltage adjustment range. If the collector voltages are different, the Fairchil effect will cause the currents to be different.
Since both transistors have the same emitter voltage and base voltage, they source the same current,  so the current on the right matches the reference current on the ua7441. Input offset voltage is the voltage that is applied between the two input terminals of the op-amp to null the output. Summary [ edit ] Description Fairchild uA opamp It turns out that transistors on a chip look nothing like this, and the base often isn’t even in the middle!
Make sure you cut near the top of the IC so you don’t hit the internal pins or the die. Both connect to an N layer, so why does it matter? Typical value of supply for IC is 2. This method is usually carried out to faiirchild the degree of matching between the inverting and non-inverting terminals. The equivalent circuit or schematic diagram of the IC is provided in the datasheet. This allows a much higher resistance for a given size.
Third, instead of multiple output transistors, you can use one transistor with multiple collectors; this seems bizarre if you are used to discrete 3-pin transistors, but is a normal thing to do in IC designs. Symbol and oversimplified structure of an NPN transistor.
With even a basic middle-school microscope, you can get a good view of the die at low magnification but for the die photos, I used a metallurgical microscopewhich shines light from above through the lens. Large signal voltage gain is the ratio between the output voltage and the voltage difference between the two input terminals. As explained earlier, resistors inside ICs are both inconveniently large and inaccurate. The lower the value of SVRR, ua7741 better will be the op-amp performance.
uA Frequency-compensated operational amplifier by Fairchild Semiconductors
I’ve vastly oversimplified op amp stability and frequency compensation. SR is the maximum rate of change of output voltage per unit of time and is expressed in volts per microseconds. But if something like that is done accidentally, the current flowing through will have a high value. For later ICs, I used a jeweler’s saw faircgild gives a cleaner cut than a hacksaw – the IC doesn’t look like it was ripped open by a bear.